Table of Contents

Modem Signal and Line States

Configuring X.25 on ISDN Using AO/DI

Configuring ISDN BRI

Leased and Switched BRI Interface for ETSI NET3

ISDN BCAC and Round-Robin Channel Selection Enhancements

Configuring ISDN Special Signaling

Configuring Snapshot Routing

Reliable Static Routing Backup Using Object Tracking

Configuring Dial Backup for Serial Lines

Configuring Dial Backup with Dialer Profiles

Dialer Watch Connect Delay

Configuring Cisco Easy IP ..

Configuring Virtual Profiles

Configuring Virtual Template Interfaces

Configuring Media-Independent PPP and Multilink PPP

Customer Profile Idle Timer Enhancements for Interesting Traffic

Troubleshooting Enhancements for Multilink PPP over ATM Link Fragmentation and Interleaving

Configuring PPP Callback

Configuring ISDN Caller ID Callback

Configuring BACP

Large-Scale Dial-Out (LSDO) VRF Aware

Configuring Asynchronous Serial Traffic Over UDP

Modem Signal and Line States

First Published: May 8, 2001

Last Updated: May 14, 2009

This chapter contains information on how to configure automatic dialing for modems and provides illustrations describing modem signal and line states.

To identify the hardware platform or software image information associated with a feature, use the Feature Navigator on Cisco.com to search for information about the feature or refer to the software release notes for a specific release. For more information, see the “Identifying Supported Platforms” section in the “Using Cisco IOS Software” chapter.

For a complete description of the modem support commands in this chapter, refer to the Cisco IOS Modem Command Reference. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the “Feature Information for Modem Signal and Line State” section.

Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Contents

- Information About Signal and Line State Diagrams

- How to Configure Modem Signal and Line States

- Additional References

- Feature Information for Modem Signal and Line State

Information About Signal and Line State Diagrams

Signal and line state diagrams accompany some of the tasks in the following sections to illustrate how the modem control works. The following diagrams are described here:

- EXEC and Daemon Creation on a Line with No Modem Control

- EXEC Creation on a Line Configured for a High-Speed Modem

- EXEC and Daemon Creation on a Line for Incoming and Outgoing Calls

- EXEC and Daemon Creation on a Line Configured for Continuos CTS

- Daemon Creation on a Line Configured for Modem Dial-Out

EXEC and Daemon Creation on a Line with No Modem Control

The diagrams show two processes:

- The “create daemon” process creates a tty daemon that handles the incoming network connection.

- The “create EXEC” process creates the process that interprets user commands. (See Figure 1 through Figure 5.)

In the diagrams, the current signal state and the signal that the line is watching are listed inside each box. The state of the line (as displayed by the show line EXEC command) is listed next to the box. Events that change that state appear in italics along the event path, and actions that the software performs are described within ovals.

Figure 1 illustrates line states when no modem control is set. The DTR output is always high, and CTS and RING are completely ignored. The Cisco IOS software starts an EXEC session when the user types the activation character. Incoming TCP connections occur instantly if the line is not in use and can be closed only by the remote host.

Figure 1 EXEC and Daemon Creation on a Line with No Modem Control

EXEC Creation on a Line Configured for a High-Speed Modem

Figure 2 illustrates the modem dialin process with a high-speed dialup modem. When the Cisco IOS software detects a signal on the RING input of an idle line, it starts an EXEC or autobaud process on that line. If the RING signal disappears on an active line, the Cisco IOS software closes any open network connections and terminates the EXEC facility. If the user exits the EXEC or the software terminates because of no user input, the line makes the modem hang up by lowering the DTR signal for 5 seconds. After 5 seconds, the modem is ready to accept another call.

Figure 2 EXEC Creation on a Line Configured for a High-Speed Modem

EXEC and Daemon Creation on a Line for Incoming and Outgoing Calls

Figure 3 illustrates the modem inout command. If the line is activated by raising the data set ready (DSR) signal, it functions exactly as a line configured with the modem dialin line configuration command described in the section “Automatically Answering a Modem”. If the line is activated by an incoming TCP connection, the line functions similarly to lines not used with modems.

Figure 3 EXEC and Daemon Creation on a Line for Incoming and Outgoing Calls

Note If your system incorporates dial-out modems, consider using access lists to prevent unauthorized use.

EXEC and Daemon Creation on a Line Configured for Continuos CTS

Figure 4 illustrates the modem cts-required command operating in the context of a continuous CTS signal. This form of modem control requires that the CTS signal be high for the entire session. If CTS is not high, the user input is ignored and incoming connections are refused (or sent to the next line in a rotary group).

Figure 4 EXEC and Daemon Creation on a Line Configured for Continuous CTS

Daemon Creation on a Line Configured for Modem Dial-Out

Figure 5 illustrates the modem callout process. When the Cisco IOS software receives an incoming connection, it raises the DTR signal and waits to see if the CTS signal is raised to indicate that the host has noticed the router DTR signal. If the host does not respond within the interval set by the modem answer-timeout line configuration command, the software lowers the DTR signal and drops the connection.

Figure 5 Daemon Creation on a Line Configured for Modem Dial-Out

How to Configure Modem Signal and Line States

To configure modem signal and line states, complete the tasks in the following sections:

- Supporting EXEC Restarts Triggered Via the Clear to Send (CTS) Hardware Line State

- Automatically Answering a Modem

- Supporting Dial-In and Dial-Out Connections

- Configuring a Line Timeout Interval

- Closing Modem Connections

- Configuring a Line to Disconnect Automatically

- Supporting Reverse Modem Connections and Preventing Incoming Calls

Supporting EXEC Restarts Triggered Via the Clear to Send (CTS) Hardware Line State

The modem cts-alarm command enables the router to react to a CTS drop from the remote device, and to clear any existing EXEC session.

The router reacts to a CTS drop from a connected asynchronous device. When a CTS drop is detected, the existing EXEC session is cleared and there is no need to wait for a timeout. This method improves the speed EXEC recovery by using hardware signals.

Note Use this feature with an asynchronous serial device that relies only on CTS for flow control. The CTS performs a role similar to that of on-hook and off-hook functionality.

To enable the router to react to a Clear to Send (CTS) drop from a remote device, and to clear an existing EXEC session, use the modem cts-alarm command in line configuration mode.

SUMMARY STEPS

1. enable

2. configure terminal

3. line line-number

4. modem cts-alarm

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

Router(config)# line line-number

Enters line configuration mode for the line number specified.

Step 4

Router(config-line)# modem cts-alarm

Configures the router to react on a CTS drop from the remote device, and to clear an existing EXEC session.

Configuring Automatic Dialing

The modem dtr-active command enables the router to initiate automatic dialin.

With the dialup capability, you can set a modem to dial the phone number of a remote router automatically. This feature offers cost savings because phone line connections are made only when they are needed—you pay for using the phone line only when there is data to be received or sent.

Using the modem dtr-active command causes a line to raise DTR signal only when there is an outgoing connection (such as reverse Telnet, NetWare Asynchronous Support Interface (NASI), or DDR), rather than leave DTR raised all the time. When raised, DTR potentially tells the modem that the router is ready to accept a call.

SUMMARY STEPS

1. enable

2. configure terminal

3. line line-number

4. modem dtr-active

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

Router(config)# line line-number

Enters line configuration mode for the line number specified.

Step 4

Router(config-line)# modem dtr-active

Configures a line to initiate automatic dialing.

Automatically Answering a Modem

The modem dialin command allows the router to configure a line to answer a modem automatically.

You also can configure the modem to answer the telephone on its own (as long as DTR is high), drop connections when DTR is low, and use its Carrier Detect (CD) signal to accurately reflect the presence of carrier. (Configuring the modem is a modem-dependent process.)

First, wire the modem CD signal (generally pin-8) to the router RING input (pin-22), then use the modem dialin command in line configuration mode.

SUMMARY STEPS

1. enable

2. configure terminal

3. line line-number

4. modem dialin

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

Router(config)# line line-number

Enters line configuration mode for the line number specified.

Step 4

Router(config-line)# modem dialin

Configures a line to automatically answer a modem.

You can turn on modem hardware flow control independently to respond to the status of router CTS input. Wire CTS to whatever signal the modem uses for hardware flow control. If the modem expects to control hardware flow in both directions, you might also need to wire modem flow control input to some other signal that the router always has high, such as the DTR signal.

Supporting Dial-In and Dial-Out Connections

The modem inout command enables the router to configure a line for both incoming and outgoing calls.

SUMMARY STEPS

1. enable

2. configure terminal

3. line line-number

4. modem inout

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

Router(config)# line line-number

Enters line configuration mode for the line number specified.

Step 4

Router(config-line)# modem inout

Configures a line for both incoming and outgoing calls.

Configuring a Line Timeout Interval

The modem answer-timeout command enables the router to change the interval that the Cisco IOS software waits for the CTS signal after raising the DTR signal in response to the DSR (the default is 15 seconds).

SUMMARY STEPS

1. enable

2. configure terminal

3. line line-number

4. modem answer-timeout

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

Router(config)# line line-number

Enters line configuration mode for the line number specified.

Step 4

Router(config-line)# modem answer-timeout

Configures a line for both incoming and outgoing calls.

Note The DSR signal is called RING on older ASM-style chassis.

Closing Modem Connections

Note The modem cts-required command was replaced by the modem printer command in Cisco IOS Release 12.2.

The modem cts-required enables the router to configure a line to close connections from a user’s terminal when the terminal is turned off and to prevent inbound connections to devices that are out of service.

SUMMARY STEPS

1. enable

2. configure terminal

3. line line-number

4. modem answer-timeout

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

Router(config)# line line-number

Enters line configuration mode for the line number specified.

Step 4

Router(config-line)# modem cts-required

Configures a line to close connections.

Configuring a Line to Disconnect Automatically

The autohangup command enables the router to configure automatic line disconnect.

The autohangup command causes the EXEC facility to issue the exit command when the last connection closes. This feature is useful for UNIX-to-UNIX copy program (UUCP) applications because UUCP scripts cannot issue a command to hang up the telephone. This feature is not used often.

SUMMARY STEPS

1. enable

2. configure terminal

3. line line-number

4. autohangup

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

Router(config)# line line-number

Enters line configuration mode for the line number specified.

Step 4

Router(config-line)# autohangup

Configures automatic line disconnect.

Supporting Reverse Modem Connections and Preventing Incoming Calls

In addition to initiating connections, the Cisco IOS software can receive incoming connections. This capability allows you to attach serial and parallel printers, modems, and other shared peripherals to the router or access server and drive them remotely from other modem-connected systems. The Cisco IOS software supports reverse TCP, XRemote, and local-area transport (LAT) connections.

The specific TCP port or socket to which you attach the device determines the type of service that the Cisco IOS software provides on a line. When you attach the serial lines of a computer system or a data terminal switch to the serial lines of the access server, the access server can act as a network front-end device for a host that does not support the TCP/IP protocols. This arrangement is sometimes called front-ending or reverse connection mode.

The Cisco IOS software supports ports connected to computers that are connected to modems. The modem callout command enables the router to configure the Cisco IOS software to function somewhat like a modem, and prevents the incoming calls.

SUMMARY STEPS

1. enable

2. configure terminal

3. line line-number

4. autohangup

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

Router(config)# line line-number

Enters line configuration mode for the line number specified.

Step 4

Router(config-line)# modem callout

Configures a line for reverse connections and prevents incoming calls.

Additional References

The following sections provide references related to the Modem Signal and Line State feature.

Related Documents

Related Topic

Document Title

Modem Configuration Commands

Cisco IOS Dial Technologies Command Reference

Modem Configuration and Management

Cisco IOS Dial Technologies Configuration Guide

Standards

Standard

Title

None

MIBs

MIB

MIBs Link

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

RFCs

RFC

Title

None

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/techsupport

Command Reference

The following commands are introduced or modified in the feature or features documented in this module. For information about these commands, see the Cisco IOS Dial Command Reference at http://cisco.com/en/US/docs/ios/dial/command/reference/dia_book.html. For information about all Cisco IOS commands, use the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or the Cisco IOS Master Command List, All Releases, at http://www.cisco.com/en/US/docs/ios/mcl/allreleasemcl/all_book.html.

- modem cts-alarm

- modem dtr-active

- modem dialin

- modem inout

- modem answer-timeout

- modem cts-required

- modem callout

Feature Information for Modem Signal and Line State

Table 1 lists the release history for this feature.

Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Note Table 1 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.

Table 1 Feature Information for Modem Signal and Line State

Feature Name

Releases

Feature Information

Automatic Modem Configuration

11.2(1)

12.0(2)T

12.0(7)T

12.2(11)YT

12.2(11)YV

12.2(13)T

12.2(4)T

12.2(8)T

12.5

12.4T

12.2SX

Automatic Modem Configuration can issue initialization strings automatically for most types of modems externally attached to the access server.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

© 2001-2009 Cisco Systems, Inc. All rights reserved.

Configuring X.25 on ISDN Using AO/DI

The chapter describes how to configure the X.25 on ISDN using the Always On/Dynamic ISDN (AO/DI) feature. It includes the following main sections:

- AO/DI Overview

- How to Configure an AO/DI Interface

- How to Configure an AO/DI Client/Server

- Configuration Examples for AO/DI

AO/DI supports PPP encapsulation on switched X.25 virtual circuits (VCs) only.

The X.25 encapsulation (per RFC 1356), PPP, Bandwidth Allocation Control Protocol (BACP), and Bandwidth Allocation Protocol (BAP) modules must be present in both the AO/DI client and server.

AO/DI relies on features from X.25, PPP, and BACP modules and must be configured on both the AO/DI client and server. BAP, if negotiated, is a subset of BACP, which is responsible for bandwidth allocation for the Multilink PPP (MLP) peers. It is recommended you configure MLP with the BAP option due to the differences between the ISDN (E.164) and X.25 (X.121) numbering formats.

To implement AO/DI, you must configure the AO/DI client and server for PPP, incorporating BAP and X.25 module commands. This task involves configuring the BRI or PRI interfaces with the appropriate X.25 commands and the dialer interfaces with the necessary PPP or BAP commands.

To identify the hardware platform or software image information associated with a feature, use the Feature Navigator on Cisco.com to search for information about the feature or refer to the software release notes for a specific release. For more information, see the “Identifying Supported Platforms” section in the “Using Cisco IOS Software” chapter.

For a complete description of the commands in this chapter, refer to the Cisco IOS Dial Technologies Command Reference, Release 12.2. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

AO/DI Overview

AO/DI functionality is based on the technology modules described in the following sections:

- PPP over X.25 Encapsulation

- Multilink PPP Bundle

- BACP/BAP

AO/DI is an on-demand service that is designed to optimize the use of an existing ISDN signaling channel (D channel) to transport X.25 traffic. The X.25 D-channel call is placed from the subscriber to the packet data service provider. The use of PPP allows protocols to be encapsulated within the X.25 logical circuit carried by the D channel. The bearer channels (B channels) use the multilink protocol without the standard Q.922 and X.25 encapsulations, and invoke additional bandwidth as needed. Optionally, BACP and BAP can be used to negotiate bandwidth allocation as required.

AO/DI takes full advantage of existing packet handlers at the central office by using an existing D channel to transport the X.25 traffic. The link associated with the X.25 D channel packet connection is used as the primary link of the multilink bundle. The D channel is a connectionless, packet-oriented link between the customer premise equipment (CPE) and the central office. Because the D channel is always available, it is possible to in turn offer “always available” services. On-demand functionality is achieved by using the B channels to temporarily boost data throughput and by disconnecting them after use. Figure 1 shows the AO/DI environment and how ISDN and X.25 resources are implemented.

Note On the client side, the X.25 switched virtual circuit (SVC) can only be terminated on an ISDN D channel; however, on the server side, the SVC can be terminated on an ISDN BRI using a D channel, a PRI using specific time slots, or a high-speed serial link.

Figure 1 AO/DI Environment

- ISDN telecommuting cost savings. Low-speed, D-channel services are typically more cost-efficient than the time-based tariffs applied to the B channels, which usually carry user data.

- Reductions in the amount of data traffic from service provider voice networks. The D-channel X.25 packets are handled at the central office by the X.25 packet handler, thereby routing these packets bypassing the switch, which reduces impact on the telephony network.

- Network access server cost reductions. AO/DI can reduce service provider network access server costs by increasing port efficiencies. Initial use of the “always on” D-channel connection lowers the contention ratio on standard circuit switched dial ports. (See Figure 2.)

Figure 2 Increasing Port Efficiency with AO/DI

PPP over X.25 Encapsulation

PPP over X.25 is accomplished through the following process:

1. The X.25 map statement on the client side creates a virtual access interface. A virtual access interface is dynamically created and configured by cloning the configuration from a dialer interface (dialer interface 1, for example).

2. The dialer interface goes into “spoofing” mode and stays in this mode until interesting traffic is seen.

3. When interesting traffic is seen, the dialer interface activates the virtual access interface, which creates the X.25 SVC. Once the SVC is established, PPP negotiation begins in order to bring up the line protocol. The client will initiate a call to the remote end server, per the x25 map ppp command.

4. When the AO/DI server receives a call intended for its X.25 map statement, the call is accepted and an event is queued to the X.25 encapsulation manager. The encapsulation manager is an X.25 process that authenticates incoming X.25 calls and AO/DI events, and creates a virtual access interface that clones the configuration from the dialer or BRI interface. Figure 3 shows the virtual interface creation process.

Figure 3 Creating a Virtual Access Interface

Multilink PPP Bundle

The multilink protocol offers load balancing, packet fragmentation, and the bandwidth allocation functionality that is key to AO/DI structure. The MLP bundle process is achieved through the following process:

1. The ppp multilink bap command initiates MLP and, subsequently, BAP. The virtual access interface that is created above the X.25 VC (over the D channel) becomes the first member link of the MLP bundle.

2. The ppp multilink idle-link command works in conjunction with the dialer load-threshold command in order to add B channels as needed to boost traffic throughput. When a B channel is added, the first member link enters “receive only” mode, allowing the link additions. When the higher throughput is no longer needed, the additional B channels are disconnected and the primary link is the only link in the bundle, the bundle disengages “receive only” mode. The X.25 SVC stays active. Figure 4 shows the MLP bundle sequence.

Figure 4 MLP Bundle Creation Sequence

MLP Encapsulation Enhancements

In previous releases of the Cisco IOS software, when MLP was used in a dialer profile, a virtual access interface was always created as the bundle. It was bound to both the B channel and the dialer profile interfaces after creation and cloning. The dialer profile interface could act as the bundle without help from a virtual access interface. But with recent software enhancements, it is no longer the virtual access interface that is added into the connected group of the dialer profile, but the dialer profile itself. The dialer profile becomes a connected member of its own connected group.

BACP/BAP

Bandwidth resources are provided by BACP, described in RFC 2125. Once the MLP peers have successfully negotiated BACP, BAP negotiates bandwidth resources in order to support traffic throughput. BAP is a subset of BACP, and it defines the methods and governing rules for adding and removing links from the bundle for MLP. BACP/BAP negotiations are achieved through the following process:

1. Once the MLP session is initiated and BACP is negotiated over the MLP bundle, the AO/DI client issues a BAP call request for additional bandwidth.

2. The AO/DI server responds with the BAP call response, which contains the phone number of the B channel to add. B channels are added, as needed, to support the demand for increased traffic throughput.

3. B channels are disconnected as the traffic load decreases.

How to Configure an AO/DI Interface

To configure X.25 on ISDN using AO/DI, perform the following tasks:

- Configuring PPP and BAP on the Client (As required)

- Configuring X.25 Parameters on the Client (As required)

- Configuring PPP and BAP on the Server (As required)

- Configuring X.25 Parameters on the Server (As required)

For examples of how to configure X.25 on ISDN using AO/DI in your network, see the section “Configuration Examples for AO/DI” at the end of this chapter.

Configuring PPP and BAP on the Client

Command

Purpose

Router(config-if)# ppp multilink bap

Enables PPP BACP bandwidth allocation negotiation.

Router(config-if)# encapsulation ppp

Enables PPP on the interface.

Router(config-if)# dialer in-band

Enables dial-on-demand routing (DDR) on the interface.

Router(config-if)# dialer load-threshold load

Sets the dialer load threshold.

Router(config-if)# dialer-group group-number

Controls access to this interface by adding it to a dialer access group.

Router(config-if)# ppp bap callback accept

(Optional) Enables the interface to initiate additional links upon peer request.

Router(config-if)# ppp bap call request

Enables the interface to initiate additional links.

Router(config-if)# dialer map protocol next-hop-address [name hostname] [spc] [speed 56 | speed 64] [broadcast] [modem-script modem-regexp] system-script system-regexp]

or

Router(config-if)# dialer string dial-string [:isdn-subaddress]

Router(config-if)# dialer string dial-string [class class-name]

- A single site (using legacy DDR)

- Multiple sites (using dialer profiles)

Configuring X.25 Parameters on the Client

Command

Purpose

Router(config-if)# x25 address address

Configures the X.25 address.

Router(config-if)# x25 htc circuit-number

Sets the highest two-way circuit number. For X.25 the default is 1024.

Router(config-if)# x25 win packets

Sets the default VC receive window size. The default is 2 packets.1

Router(config-if)# x25 wout packets

Sets the default VC transmit window size. The default is 2 packets.[1]

1.The default input and output window sizes are typically defined by your network administrator. Cisco IOS configured window sizes must be set to match the window size of the network.

For details and usage guidelines for X.25 configuration parameters, refer to the Cisco IOS Wide-Area Networking Configuration Guide and Cisco IOS Wide-Area Networking Command Reference.

Configuring PPP and BAP on the Server

To configure PPP and BAP under the dialer interface on the AO/DI server, use the following commands in interface configuration mode as needed:

Command

Purpose

Router(config-if)# ppp multilink bap

Enables PPP BACP bandwidth allocation negotiation.

Router(config-if)# encapsulation ppp

Enables PPP on the interface.

Router(config-if)# dialer in-band

Enables DDR on the interface.

Router(config-if)# dialer load-threshold load

Sets the dialer load threshold.

Router(config-if)# dialer-group group-number

Controls access to this interface by adding it to a dialer access group.

Router(config-if)# ppp bap call accept

Enables the interface to accept additional links upon peer request.

Router(config-if)# ppp bap callback request

BAP configuration commands are optional. For information on how to configure BACP/BAP see the chapter “Configuring BACP” later in this publication.

Configuring X.25 Parameters on the Server

The AO/DI server BRI, PRI, or serial interface must be configured for the X.25 parameters necessary to run PPP over X.25. To configure the interface for X.25 parameters, use the following commands in interface configuration mode as needed:

Command

Purpose

Router(config-if)# x25 address address

Configures the X.25 address.

Router(config-if)# x25 htc circuit-number

Sets the highest two-way circuit number. For X.25 the default is 1024.

Router(config-if)# x25 win packets

Sets the default VC receive window size. The default is 2 packets.2

Router(config-if)# x25 wout packets

Sets the default VC transmit window size. The default is 2 packets.[1]

2.The default input and output window sizes are typically defined by your network administrator. Cisco IOS configured window sizes must be sets to match the window size of the network.

For details and usage guidelines for X.25 configuration parameters, see the Cisco IOS Wide-Area Networking Configuration Guide and Cisco IOS Wide-Area Networking Command Reference.

How to Configure an AO/DI Client/Server

Once the AO/DI client and server are configured with the necessary PPP, BAP, and X.25 commands, configure the routers to perform AO/DI. Perform the tasks in the following sections:

- Configuring the AO/DI Client (Required)

- Configuring the AO/DI Server (Required)

Configuring the AO/DI Client

To configure AO/DI, you must complete the tasks in the following section. The last task, to define local number peer characteristics, is optional.

- Enabling AO/DI on the Interface (Required)

- Enabling the AO/DI Interface to Initiate Client Calls (Required)

- Enabling the MLP Bundle to Add Multiple Links (Required)

- Modifying BACP Default Settings (Optional)

See the section “AO/DI Client Configuration Example” at the end of this chapter for an example of how to configure the AO/DI client.

Enabling AO/DI on the Interface

Command

Purpose

Router(config-if)# x25 aodi

Enables the AO/DI client on an interface.

Enabling the AO/DI Interface to Initiate Client Calls

You must enable the interface to establish a PPP session over the X.25 protocol. The cloning interface will hold the PPP configuration, which will be cloned by the virtual access interface that is created and attached to the X.25 VC. The cloning interface must also hold the MLP configuration that is needed to run AO/DI.

Command

Purpose

Router(config-if)# x25 map ppp x121-address interface cloning-interface

Enables the interface to initiate a PPP session over the X.25 protocol and remote end mapping.

Enabling the MLP Bundle to Add Multiple Links

Once MLP is enabled and the primary traffic load is reached (based on the dialer load-threshold value), the MLP bundle will add member links (B channels). The addition of another B channel places the first link member into “receive-only” mode and subsequent links are added, as needed.

Command

Purpose

Router(config-if)# ppp multilink idle-link

Configures the interface to enter “receive only” mode so that MLP links are added as needed.

Modifying BACP Default Settings

During BACP negotiation between peers, the called party indicates the number to call for BACP. This number may be in either a national or subscriber format. A national format indicates that the phone number returned from the server to the client should contain ten digits. A subscriber number format contains seven digits.

Command

Purpose

Router(config-if)# ppp bap number prefix prefix-number

(Optional) specifies a primary telephone number prefix for a peer to call for PPP BACP negotiation.

Note The ppp bap number prefix command is not typically required on the server side, as the server usually does not initiate calls to the client. This command would only be used on the server in a scenario where both sides are configured to act as both client and server.

Configuring the AO/DI Server

The AO/DI server will receive calls from the remote end interface running AO/DI client and likewise, and must be configured to initiate a PPP session over X.25, allow interface cloning, and be capable of adding links to the MLP bundle. The interface configured for AO/DI server relies on the no-outgoing option for the x25 map command to ensure calls are not originated by the interface. Use the commands in the following sections to configure the AO/DI server:

- Enabling the Interface to Receive AO/DI Client Calls (Required)

- Enabling the MLP Bundle to Add Multiple Links (Required)

- Modifying BACP Default Settings (Optional)

See the section “AO/DI Server Configuration Example” at the end of this chapter for an example of how to configure the AO/DI server.

Enabling the Interface to Receive AO/DI Client Calls

Configure the x25 map command with the X.121 address of the calling client. This task enables the AO/DI server interface to run a PPP over X.25 session with the configured client. The no-outgoing option must be set in order to ensure that calls do not originate from this interface.

To configure an interface for AO/DI server, use the following command in interface configuration mode:

Command

Purpose

Router(config-if)# x25 map ppp x121-address interface cloning-interface no-outgoing

Enables the interface to initiate a PPP session over the X.25 protocol and remote end mapping.

Enabling the MLP Bundle to Add Multiple Links

Once MLP is enabled and the primary traffic load is reached (based on the dialer load-threshold value), the MLP bundle will add member links (B channels). The addition of another B channel places the first link member into “receive-only” mode and subsequent links are added, as needed.

Command

Purpose

Router(config-if)# ppp multilink idle-link

Configures the interface to enter “receive only” mode so that MLP links are added as needed.

Modifying BACP Default Settings

During BACP negotiation between peers, the called party indicates the number to call for BACP. This number may be in either a national or subscriber format. A national format indicates that the phone number returned from the server to the client should contain 10 digits. A subscriber number format contains 7 digits.

Command

Purpose

Router(config-if)# ppp bap number {format national | subscriber}

(Optional) Specifies that the primary telephone number for a peer to call is in either a national or subscriber number format.

Note The ppp bap number prefix command is not typically required on the server side, because the server usually does not initiate calls to the client. This command would only be used on the server in a scenario where both sides are configured to act as both client and server.

Configuration Examples for AO/DI

This section provides the following configuration examples:

- AO/DI Client Configuration Example

- AO/DI Server Configuration Example

AO/DI Client Configuration Example

The following example shows BRI interface 0 configured with the PPP, multilink, and X.25 commands necessary for the AO/DI client:

hostname Router_client

!

ip address-pool local

isdn switch-type basic-5ess

x25 routing

!

interface Ethernet0

ip address 172.21.71.99 255.255.255.0

!

interface BRI0

isdn switch-type basic-5ess

ip address 10.1.1.9 255.0.0.0

encap ppp

dialer in-band

dialer load-threshold 1 either

dialer-group 1

no fair-queue

ppp authentication chap

ppp multilink bap

ppp bap callback accept

ppp bap call request

ppp bap number prefix 91

ppp multilink idle-link

isdn x25 static-tei 23

isdn x25 dchannel

dialer rotary-group 1

!

interface BRI0:0

no ip address

x25 address 12135551234

x25 aodi

x25 htc 4

x25 win 3

x25 wout 3

x25 map ppp 12135556789 interface bri0

!

dialer-list 1 protocol ip permit

AO/DI Server Configuration Example

The following example shows the configuration for the AO/DI server, which is configured to only receive calls from the AO/DI client. The configuration uses the x25 map ppp command with the no-outgoing option, and the ppp bap number format command, which implements the national format.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2001–2009 Cisco Systems, Inc. All rights reserved.

Configuring ISDN BRI

First Published: February 26, 2003

Last Updated: November 24, 2010

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the “Feature Information for Configuring ISDN BRI” section.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Contents

- Information About ISDN BRI

- How to Configure ISDN BRI

- Configuration Examples for Configuring ISDN BRI

- Additional References

- Feature Information for Configuring ISDN BRI

Information About ISDN BRI

The Cisco IOS software provides an enhanced Multiple ISDN Switch Types feature that allows you to apply an ISDN switch type to a specific ISDN interface and configure more than one ISDN switch type per router. This feature allows both ISDN BRI and ISDN PRI to run simultaneously on platforms that support both interface types. Cisco IOS software supports both the ISDN BRI and the ISDN PRI.

ISDN BRI provides two bearer (B) channels, each capable of transferring voice or data at 64 kb/s, and one 16 kb/s data (D) signaling channel, which is used by the telephone network to carry instructions about how to handle each of the B channels. ISDN BRI (also referred to as 2 B + D) provides a maximum transmission speed of 128 kb/s, but many users use only half the available bandwidth. This section covers the following topics:

- Requesting BRI Line and Switch Configuration from a Telco Service Provider

- Interface Configuration

- Multiple ISDN Switch Types Feature

Requesting BRI Line and Switch Configuration from a Telco Service Provider

Before configuring ISDN BRI on your Cisco router, you must order a correctly configured ISDN line from your telecommunications service provider. This process varies from provider to provider on a national and international basis. However, some general guidelines follow:

- Ask for two channels to be called by one number.

- Ask for delivery of calling line identification. Providers sometimes call this CLI or automatic number identification (ANI).

- Ask for a point-to-point service and a data-only line if the router will be the only device attached to the BRI.

- Ask for point-to-multipoint service (subaddressing is required) and a voice-and-data line if the router will be attached to an ISDN bus (to which other ISDN devices might be attached).

When you order ISDN service for switches used in North America, request the BRI switch configuration attributes specified in Table 1.

Table 1 North American ISDN BRI Switch Type Configuration Information

Switch Type

Configuration

DMS-100 BRI Custom

2 B channels for voice and data.

2 directory numbers assigned by service provider.

2 service profile identifiers (SPIDs) required; assigned by service provider.

Functional signaling.

Dynamic terminal endpoint identifier (TEI) assignment.

Maximum number of keys = 64.

Release key = no, or key number = no.

Ringing indicator = no.

EKTS = no.

PVC = 2.

Request delivery of calling line ID on Centrex lines.

Set speed for ISDN calls to 56 kb/s outside local exchange.

Directory number 1 can hunt to directory number 2.

5ESS Custom BRI

For Data Only

2 B channels for data.

Point to point.

Terminal type = E.

1 directory number (DN) assigned by service provider.

MTERM = 1.

Request delivery of calling line ID on Centrex lines.

Set speed for ISDN calls to 56 kb/s outside local exchange.

For Voice and Data

(Use these values only if you have an ISDN telephone connected.)

2 B channels for voice or data.

Multipoint.

Terminal type = D.

2 directory numbers assigned by service provider.

2 SPIDs required; assigned by service provider.

MTERM = 2.

Number of call appearances = 1.

Display = No.

Ringing/idle call appearances = idle.

Autohold = no.

Onetouch = no.

Request delivery of calling line ID on Centrex lines.

Set speed for ISDN calls to 56 kb/s outside local exchange.

Directory number 1 can hunt to directory number 2.

5ESS National ISDN (NI) BRI

Terminal type = A.

2 B channels for voice and data.

2 directory numbers assigned by service provider.

2 SPIDs required; assigned by service provider.

Set speed for ISDN calls to 56 kb/s outside local exchange.

Directory number 1 can hunt to directory number 2.

EZ-ISDN 1

For Voice and Data

- ISDN Ordering Code for Cisco 766/776 Series = Capability S

- ISDN Ordering Code for Cisco 1604 Series = Capability R

2 B channels featuring alternate voice and circuit-switched data. Non-EKTS voice features include the following:

- Flexible Calling

- Call Forwarding Variable

- Additional Call Offering

- Calling Number Identification (includes Redirecting Number Delivery)

Interface Configuration

The Cisco IOS software also provides custom features for configuring the ISDN BRI interface. The interface provides capabilities like call screening, called party-number verification, and ISDN default cause code override. For European and Australian customers, the interface provides Dialed Number Identification Service (DNIS)-plus-ISDN-subaddress binding to allow multiple binds between a dialer profile and an ISDN B channel.

Multiple ISDN Switch Types Feature

The Cisco IOS software provides an enhanced Multiple ISDN Switch Types feature that allows you to apply an ISDN switch type to a specific ISDN interface and configure more than one ISDN switch type per router. This feature allows both ISDN BRI and ISDN PRI to run simultaneously on platforms that support both interface types.

This section covers the following topics:

- Dynamic Multiple Encapsulations

- Interface Configuration Options

- ISDN Cause Codes

Dynamic Multiple Encapsulations

Prior to Cisco IOS Release 12.1, encapsulation techniques such as Frame Relay, High-Level Data Link Control (HDLC), Link Access Procedure, Balanced-Terminal Adapter (LAPB-TA), and X.25 could support only one ISDN B-channel connection over the entire link. HDLC and PPP could support multiple B channels, but the entire ISDN link needed to use the same encapsulation. The Dynamic Multiple Encapsulations feature introduced in Cisco IOS Release 12.1 allows various encapsulation types and per-user configurations on the same ISDN B channel at different times depending on the type of incoming call.

With the Dynamic Multiple Encapsulations feature, once calling line identification (CLID) binding is completed, the topmost interface is always used for all configuration and data structures. The ISDN B channel becomes a forwarding device, and the configuration on the D channel is ignored, thereby allowing the different encapsulation types and per-user configurations. Dynamic multiple encapsulations provide support for packet assembler/disassembler (PAD) traffic and X.25 encapsulated and switched packets. For X.25 encapsulations, the configurations reside on the dialer profile.

Dynamic multiple encapsulation is especially important in Europe, where ISDN is relatively expensive and the maximum use of all the 30 B channels on the same ISDN link is desirable. Further, the feature removes the need to statically dedicate channels to a particular encapsulation and configuration type, and improves channel usage.

Figure 1 shows a typical configuration for an X.25 network in Europe. The Dynamic Multiple Encapsulations feature allows the use of all the 30 B channels, and supports calls that originate in diverse areas of the network and converge on the same ISDN PRI.

Figure 1 European X.25 Network

Interface Configuration Options

You can also optionally configure the snapshot routing for the ISDN interfaces. Snapshot routing is a method of dynamically learning remote routes and keeping the routes available for a specified period of time, even though routing updates are not exchanged during that period.

To place calls on an ISDN interface, you must configure the interface with dial-on-demand routing (DDR). For configuration information about ISDN by using DDR, see the “Dial-on-Demand Routing Configuration” part of this publication. For command information, refer to the Cisco IOS Dial Technologies Command Reference.

To configure the bandwidth on demand, see the modules “Configuring Legacy DDR Spokes” or “Configuring Legacy DDR Hubs” in the Cisco IOS Dial Solutions Configuration Guide.

ISDN Cause Codes

A cause code is an information element (IE) that indicates why an ISDN call failed or was disconnected. When the originating gateway receives a Release Complete message, it generates a tone corresponding to the cause code in the message.

Table 2 Cause Codes Generated by the Cisco VoIP Gateway

Cause Code

Description

Explanation

Tone

1

Unallocated (unassigned) number

The ISDN number is not assigned to any destination equipment.

Reorder

3

No route to destination

The call was routed through an intermediate network that does not serve the destination address.

Reorder

16

Normal call clearing

Normal call clearing has occurred.

Dial

17

User busy

The called system acknowledged the connection request but was unable to accept the call because all B channels were in use.

Busy

19

No answer from user (user alerted)

The destination responded to the connection request but failed to complete the connection within the prescribed time. The problem is at the remote end of the connection.

Reorder

28

Invalid number format

The connection could not be established because the destination address was presented in an unrecognizable format or because the destination address was incomplete.

Reorder

34

No circuit/channel available

The connection could not be established because no appropriate channel was available to take the call.

Reorder

For a complete list of ISDN cause codes that are generated by the switch, refer to “Appendix B: ISDN Switch Types, Codes and Values” in the Cisco IOS Debug Command Reference.

Although the VoIP gateway generates the cause codes listed in Table 2 by default, there are commands introduced in previous Cisco IOS releases that can override these defaults, thereby allowing the gateway to send different cause codes to the switch. The following commands override the default cause codes:

- isdn disconnect-cause —Sends the specified cause code to the switch when a call is disconnected.

- isdn network-failure-cause —Sends the specified cause code to the switch when a call fails because of internal network failures.

- isdn voice-call-failure —Sends the specified cause code to the switch when an inbound voice call fails with no specific cause code.

When you implement these commands, the configured cause codes are sent to the switch; otherwise, the default cause codes of the voice application are sent. For a complete description of these commands, refer to the Cisco IOS Dial Technologies Command Reference.

How to Configure ISDN BRI

To configure ISDN lines and interfaces, perform the following tasks:

- Configuring the ISDN BRI Switch (required)

- Specifying Interface Characteristics for an ISDN BRI (required)

- Configuring ISDN Semipermanent Connections (required)

- Configuring ISDN BRI for Leased-Line Service (required)

- Monitoring and Maintaining ISDN Interfaces (optional)

- Troubleshooting ISDN Interfaces (optional)

See the Monitoring and Maintaining ISDN Interfaces sections on page 452 and the “Troubleshooting ISDN Interfaces” section on page 453 in this module for tips on maintaining your network. See the section “Configuration Examples for Configuring ISDN BRI” section on page 455 for sample configurations.

To configure ISDN BRI for voice, video, and fax applications, refer to the Cisco IOS Voice, Video, and Fax Applications Configuration Guide.

Configuring the ISDN BRI Switch

To configure the ISDN switch type, perform the following tasks:

- Configuring the Switch Type (required)

- Checking and Setting the Buffers (required)

- Configuring Buffers and MTU Size (required)

Configuring the Switch Type

Perform this task to configure the switch type.

SUMMARY STEPS

1. enable

2. configure terminal

3. isdn switch-type switch-type

4. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

isdn switch-type switch-type

Router(config)# isdn switch-type basic-ni

Step 4

end

Router(config# end

Exits global configuration mode.

The “Example: Configuring a Global ISDN and BRI Interface Switch Type” section on page 454 provides an example of configuring the ISDN BRI switch.

Table 3 ISDN Service Provider BRI Switch Types

Switch Type Keywords

Description/Use

Central Office (CO) Switch Type?

Voice/PBX Systems

basic-qsig

Australia, Europe, and UK

basic-1tr6

German 1TR6 ISDN switch

Yes

basic-net3

NET3 ISDN BRI for Norway NET3, Australia NET3, and New Zealand NET3 switches; covers ETSI-compliant Euro-ISDN E-DSS1 signaling system

Yes

vn3

French VN3 ISDN BRI switch

Yes

Japan

ntt

North America

basic-5ess

Lucent (AT&T) basic rate 5ESS switch

Yes

basic-dms100

Nortel basic rate DMS-100 switch

Yes

basic-ni

National ISDN switch

Yes

All Users

none

Note The command parser will still accept the following switch type keywords: basic-nwnet3, vn2, and basic-net3; however, when viewing the NVRAM configuration, the basic-net3 and vn3 switch type keywords are displayed respectively.

Checking and Setting the Buffers

When configuring a BRI interface, after the system starts up, make sure that the free list of the buffer pool has enough buffers that match the maximum transmission unit (MTU) of your BRI interface. If not, you must reconfigure buffers in order for the BRI interfaces to function properly.

Perform this task to check the MTU size and buffers.

SUMMARY STEPS

1. enable

2. show interfaces bri number

3. show buffers

4. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router# enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

show interfaces bri number

Router# show interfaces bri 0

Displays the MTU size.

Step 3

show buffers

Router# show buffers

Step 4

end

Router# end

Exits privileged EXEC configuration mode.

Configuring Buffers and MTU Size

Perform this task to configure the buffers and the MTU size.

SUMMARY STEPS

1. enable

2. configure terminal

3. buffers {{header | fastswitching | interface number | small | middle | big | verybig | large | huge {initial | max-free | min-free | permanent} buffers} | particle-clone particle-clones | element {minimum | permanent} elements}

4. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

buffers {{header | fastswitching | interface number | small | middle | big | verybig | large | huge {initial | max-free | min-free | permanent} buffers} | particle-clone particle-clones | element {minimum | permanent} elements}

Router(config)# buffers big

Configures the size of the buffer and the initial public buffer pool settings.

Step 4

end

Router# end

Exits global configuration mode.

Specifying Interface Characteristics for an ISDN BRI

Perform the following tasks to set interface characteristics for an ISDN BRI interface irrespective of whether it is the only BRI in a router or is one of many. Each of the BRIs can be configured separately.

- Specifying the Interface and Its IP Address

- Specifying ISDN SPIDs

- Configuring Encapsulation on ISDN BRI

- Configuring Network Addressing

- Configuring TEI Negotiation Timing

- Configuring CLI Screening

- Configuring Called-Party Number Verification

- Configuring ISDN Calling Number Identification

- Configuring the Line Speed for Calls Not ISDN End to End

- Configuring a Fast Rollover Delay

- Overriding ISDN Application Default Cause Codes

- Configuring Inclusion of the Sending Complete Information Element

- Configuring DNIS-plus-ISDN-Subaddress Binding

- Screening Incoming V.110 Modem Calls

- Disabling V.110 Padding

- Configuring Leased-Line Service at Normal Speeds

- Configuring Leased-Line Service at 128 Kb/s

Specifying the Interface and Its IP Address

Perform this task to enter interface configuration mode and specify an ISDN BRI.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. ip address address mask

5. end

DETAILED STEPS

Command

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Router(config)# interface bri 0

Cisco 7200 series router only

Router(config)# interface bri slot/port

Specifies the interface and enters interface configuration mode.

Step 4

ip address address mask

Router(config-if)# ip address ip 209.165.200.225 255.255.255.224

Specifies an IP address for the interface.

Step 5

end

Router# end

Exits interface configuration mode.

Specifying ISDN SPIDs

Some service providers use service profile identifiers (SPIDs) to define the services subscribed to by the ISDN device that is accessing the ISDN service provider. The service provider assigns the ISDN device one or more SPIDs when you first subscribe to the service. If you are using a service provider that requires SPIDs, your ISDN device cannot place or receive calls until it sends a valid, assigned SPID to the service provider when accessing the switch to initialize the connection.

Currently, only the DMS-100 and NI switch types require SPIDs. The AT&T 5ESS switch type may support a SPID, but we recommend that you set up the ISDN service without SPIDs. In addition, SPIDs have significance only at the local access ISDN interface. Remote routers never receive the SPID.

A SPID is usually a seven-digit telephone number with some optional numbers. However, service providers may use different numbering schemes. The DMS-100 switch type has two SPIDs — one for each B channel.

The isdn spid1 and isdn spid2 commands enable the router to define the SPIDs and the local directory number (LDN) on the router.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. isdn spid1 word

5. isdn spid2 word

6. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Router(config)# interface BRI 0

Specifies the interface and begins interface configuration mode.

Step 4

isdn spid1 word

Router(config-if)# isdn spid1 415988488201

Specifies a SPID and a name for the B1 channel.

Step 5

isdn spid2 word

Router(config-if)# isdn spid2 415988488302

Specifies a SPID and a name for the B2 channel.

Step 6

end

Router# end

Exits interface configuration mode and returns to global configuration mode.

The LDN is optional but might be necessary if the router is to answer calls made to the second directory number.

Configuring Encapsulation on ISDN BRI

Each ISDN B channel is treated as a synchronous serial line, and the default serial encapsulation is HDLC. The Dynamic Multiple Encapsulations feature allows incoming calls over ISDN to be assigned an encapsulation type such as Frame Relay, PPP, and X.25, based on CLID or DNIS. PPP encapsulation is configured for most ISDN communication.

Perform this task to configure encapsulation on the ISDN BRI.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. encapsulation [ppp | lapb | hdlc | x25]

5. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Router(config)# interface BRI 0

Specifies the interface and enters interface configuration mode.

Step 4

encapsulation [ppp | lapb | hdlc | x25]

Router(config-if)# encapsulation ppp

Configures the encapsulation type.

Step 5

end

Router(config-if)# end

Exits interface configuration mode and returns to global configuration mode.

Verifying the Dynamic Multiple Encapsulations Feature

To verify dialer interfaces configured for binding and to see statistics on each physical interface bound to the dialer interface, use the show interfaces command.

Encapsulation Configuration Notes

The router might need to communicate with devices that require a different encapsulation protocol or the router might send traffic over a Frame Relay or X.25 network. The Dynamic Multiple Encapsulations feature provides bidirectional support of all serial encapsulations except Frame Relay.

To configure the router for automatic detection of encapsulation type on incoming calls, or to configure encapsulation for Cisco 700 and 800 series (formerly Combined) router compatibility, see the section “Configuring Automatic Detection of Encapsulation Type” in the module “Configuring ISDN Special Signaling” in this publication.

Configuring Network Addressing

Perform this task to configure network addressing.

This task supports the primary goals of network addressing:

- Define the packets that are interesting and those that will cause the router to make an outgoing call.

- Define the remote host where the calls are going.

- Specify whether broadcast messages will be sent.

- Specify the dialing string to be used in the call.

Intermediate steps that use shared argument values tie the host identification and dial string to the interesting packets to be sent to that host.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. dialer map protocol-keyword protocol-next-hop-address name hostname speed [56 | 64] dial-string[:isdn-subaddress]

or

dialer map protocol next-hop-address name hostname spc [speed 56 | 64] [broadcast] dial-string[:isdn-subaddress]

5. dialer-group group-number

6. exit

7. dialer-list dialer-group protocol protocol-name {permit | deny | list access-list-number | access-group}

8. access-list access-list-number {deny | permit} protocol source address source-mask destination destination-mask

9. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Router(config)# interface BRI 0

Specifies the interface and begins interface configuration mode.

Step 4

dialer map protocol-keyword protocol-next-hop-address name hostname speed [56 | 64] dial-string[:isdn-subaddress]

Router(config-if)# dialer map 172.19.1.8 name abc speed 64 zzz 14155550134

dialer map protocol

next-hop-address name hostname spc [speed 56 | 64] [broadcast] dial-string[:isdn-subaddress]

Router(config-if)# dialer map ip

172.16.0.0 name user1 spc 64 broadcast zzz 14155550134

(Germany) Uses the command keyword that enables ISDN semipermanent connections.

Step 5

dialer-group group-number

Router(config-if)# dialer-group 1

Assigns the interface to a dialer group to control access to the interface.

Step 6

exit

Router(config-if)# exit

Exits to global configuration mode.

Step 7

dialer-list dialer-group protocol protocol-name {permit | deny | list access-list-number

|access-group}

Router(config)# dialer-list 1 protocol ip list 101

Defines a dial-on-demand routing (DDR) dialer list for dialing by protocol or by a combination of a protocol and an access list.

Step 8

access-list access-list-number {deny | permit} protocol source address source-mask destination destination-mask

Router(config)# access-list 202 deny ip 192.0.2.0 255.255.255.224 192.0.2.3

255.255.255.224

Defines an access list permitting or denying access to specified protocols, sources, or destinations. Permitted packets cause the router to place a call to the destination protocol address.

Step 9

exit

Router(config)# exit

Exits global configuration mode.

German networks allow semipermanent connections between customer routers with BRIs and the 1TR6 basic rate switches in the exchange. Semipermanent connections are less expensive than leased lines.

Note The access list reference in Step 8 of this task is an example of the access-list commands allowed by different protocols. Some protocols might require a different command form or might require multiple commands. Refer to the relevant protocol module in the network protocol configuration guide (the Cisco IOS Novell IPX Configuration Guide, for example) for more information about setting up access lists for a protocol.

For more information about defining outgoing call numbers, see the modules “Configuring Legacy DDR Hubs” and “Configuring Legacy DDR Spokes” in the Cisco IOS Dial Solutions Configuration Guide.

Configuring TEI Negotiation Timing

Perform this task to configure terminal endpoint identifier (TEI) negotiation timing.

The isdn tei command enables the router to apply the TEI negotiation to a specific BRI interface.

You can configure the ISDN TEI negotiation on individual ISDN interfaces. The TEI negotiation is useful for switches that may deactivate Layers 1 or 2 when there are no active calls. Typically, this setting is used for ISDN service offerings in Europe and connections to DMS-100 switches that are designed to initiate the TEI negotiation.

By default, TEI negotiation occurs when the router is powered up. The TEI negotiation value configured on an interface overrides the default or global TEI value. For example, if you configure isdn tei first-call globally and isdn tei powerup on BRI interface 0, then the TEI negotiation powerup is the value applied to BRI interface 0. It is not necessary to configure TEI negotiation unless you wish to override the default value (isdn tei powerup).

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. isdn tei [first-call | powerup | preserve | remove]

5. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Router(config)# interface BRI 0

Specifies the interface and begins interface configuration mode.

Step 4

isdn tei [first-call | powerup | preserve | remove]

Router(config-if)# isdn tei first-call

Determines when ISDN TEI negotiation occurs.

Step 5

end

Router(config-if)# exit

Exits interface configuration mode and returns to global configuration mode.

Configuring CLI Screening

Perform this task to configure CLI screening.

CLI screening adds a level of security by allowing you to screen incoming calls. You can verify that the calling line ID is from an expected origin. CLI screening requires a local switch that is capable of delivering the CLI to the router.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. isdn caller word

5. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Router(config)# interface BRI 0

Specifies the interface and enters interface configuration mode.

Step 4

isdn caller word

Router(config-if)# isdn caller 415988488201

Configures caller ID screening.

Step 5

end

Router(config-if)# end

Exits interface configuration mode and returns to global configuration mode.

Note If caller ID screening is configured and the local switch does not deliver caller IDs, the router rejects all calls.

Note In releases prior to Cisco IOS Release 12.1, ISDN accepted all synchronous calls and performed some minimal CLI screening before accepting or rejecting a call. Beginning with Cisco IOS Release 12.1, DDR provides a separate process that screens for the profile of the caller. The new screening process also checks that enough resources are available to accept the call and that the call conforms to predetermined rules. When the call is found acceptable, the screening process searches for a matching profile for the caller. The call is accepted only when there is a matching profile.

Configuring Called-Party Number Verification

Perform this task to configure called-party number verification.

When multiple devices are attached to an ISDN BRI, you can ensure that only a single device answers an incoming call by verifying the number or subaddress in the incoming call against the configured number or subaddress or both of the device.

You can specify that the router verifies the called-party number or subaddress number in the incoming setup message for ISDN BRI calls, if the number is delivered by the switch. You can do so by configuring the number that is allowed.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. isdn answer1 [called-party-number] [:subaddress]

5. isdn answer2 [called-party-number] [:subaddress]

6. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Router(config)# interface BRI 0

Specifies the interface and begins interface configuration mode.

Step 4

isdn answer1 [called-party-number] [:subaddress]

Router(config-if)# isdn answer1 [123][:56789]

Specifies that the router verify a called-party number or subaddress number in the incoming setup message.

Step 5

isdn answer2 [called-party-number] [:subaddress]

Router(config-if)# isdn answer2 [567][:45903]

Specifies that the router verify a second called-party number or subaddress number in the incoming setup message.

Step 6

end

Router(config-if)# end

Exits interface configuration mode and returns to global configuration mode.

Verifying the called-party number ensures that only the desired router responds to an incoming call. If you want to allow an additional number for the router, you can configure it, too.

Configuring ISDN Calling Number Identification

A router with an ISDN BRI interface might need to supply the ISDN network with a billing number for outgoing calls. Some networks offer better pricing on calls that display the number. When configured, this information is included in the outgoing call Setup message.

Perform this task to configure the interface to identify the billing number.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. isdn calling-number word

5. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Router(config)# interface BRI 0

Specifies the interface and enters interface configuration mode.

Step 4

isdn calling-number word

Router(config-if)# isdn calling-number 415988488201

Specifies the calling party number.

Step 5

end

Router(config-if)# end

Exits interface configuration mode and returns to global configuration mode.

The isdn calling-number command can be used with all switch types except German 1TR6 ISDN BRI switches.

Configuring the Line Speed for Calls Not ISDN End to End

Perform this task to configure the line speed for calls that are not ISDN from end to end.

When calls are made at 56 kb/s but delivered by the ISDN network at 64 kb/s, the incoming data can get corrupted. However, on ISDN calls, if the receiving side is informed that the call is not an ISDN call from end to end, the ISDN network can set the line speed for the incoming call.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. isdn not-end-to-end {56 | 64}

5. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Router(config)# interface BRI 0

Specifies the interface and enters interface configuration mode.

Step 4

isdn not-end-to-end {56 | 64}

Router(config-if)# isdn not-end-to-end 56

Sets the speed to be used for incoming calls recognized as not ISDN end to end.

Step 5

end

Router(config-if)# end

Exits interface configuration mode and returns to global configuration mode.

Configuring a Fast Rollover Delay

Perform this task to configure a fast rollover delay.

Sometimes a router attempts to dial a call on an ISDN B channel before the previous call is completely torn down. The fast rollover fails because the second call is made to a different number before the B channel is released from the unsuccessful call. This failure might occur in the following ISDN configurations:

- The two B channels of the BRI are not configured as a hunt group, but have separate numbers defined.

- The B channel is not released by the ISDN switch until after Release Complete signal is processed.

You need to configure this delay if a BRI on a remote peer has two phone numbers configured one for each B channel you are dialing into this BRI. You also need to configure this delay if you have a dialer map for each phone number and the first call succeeds but a second call fails with no channel available.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. isdn fast-rollover-delay seconds

5. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Router(config)# interface BRI 0

Specifies the interface and begins interface configuration mode.

Step 4

isdn fast-rollover-delay seconds

Router(config-if)# isdn fast-rollover-delay 56

Defines a fast rollover delay.

Step 5

end

Router(config-if)# end

Exits interface configuration mode and returns to global configuration mode.

A delay of 5 seconds should cover most cases. Configure sufficient delay to ensure the ISDN RELEASE_COMPLETE message has been sent or received before making the fast rollover call. Use the debug isdn q931 command to display this information. This pattern of failed second calls is a rare occurrence.

Overriding ISDN Application Default Cause Codes

Perform this task to override ISDN application default cause codes.

The ISDN Cause Code Override function is useful for overriding the default cause code of ISDN applications. When this feature is implemented, the configured cause code is sent to the switch; otherwise, default cause codes of the application are sent.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. isdn disconnect-cause {cause-code-number | busy | not-available}

5. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Router(config)# interface BRI 0

Specifies the interface and begins interface configuration mode.

Step 4

isdn disconnect-cause {cause-code-number | busy | not-available}

Router(config-if)# isdn disconnect-cause not-available

Specifies the ISDN cause code to be sent to the switch.

Step 5

end

Router(config-if)# end

Exits interface configuration mode and returns to global configuration mode.

Examples

The following example sends a BUSY cause code to the switch when an application fails to complete the call:

interface serial 0:23

isdn disconnect-cause busy

Verifying ISDN Cause Code Override

To verify that the ISDN Cause Code Override feature is operating correctly, enter the debug q931 command. The debug q931 command displays a report of any configuration irregularities.

Configuring Inclusion of the Sending Complete Information Element

Perform this task to configure inclusion of the sending complete information element. In some geographic locations, such as Hong Kong and Taiwan, ISDN switches require that the Sending Complete information element be included in the outgoing Setup message to indicate that the entire number is included. This information element is generally not required in other locations.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. isdn sending-complete

5. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Router(config)# interface BRI 0

Specifies the interface and enters interface configuration mode.

Step 4

isdn sending-complete

Router(config-if)# isdn sending-complete

Includes the Sending Complete information element in the outgoing call Setup message.

Step 5

end

Router(config-if)# end

Exits interface configuration mode and returns to global configuration mode.

Configuring DNIS-plus-ISDN-Subaddress Binding

Perform this task to configure DNIS-plus-ISDN-subaddress binding.

SUMMARY STEPS

1. enable

2. configure terminal

3. dialer called dnis:subaddress

4. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

dialer called dnis:subaddress

Router(config)# dialer called 12345:6789

Binds a DNIS to an ISDN subaddress.

Step 4

end

Router(config)# end

Exits global configuration mode.

Note The dialer called command allows multiple binds between a dialer profile and an ISDN B channel. The configuration requires an ISDN subaddress, which is used in Europe and Australia.

See the section “Example: DNIS-plus-ISDN-Subaddress Binding” on page 458 in this module for a configuration example.

Screening Incoming V.110 Modem Calls

Perform this task to screen incoming V.110 modem calls. You can screen incoming V.110 modem calls and reject calls that do not have the communications settings configured according to the network.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. isdn v110 only [databits {5 | 7 | 8}] [parity {even | mark | none | odd | space}] [stopbits {1 | 1.5 | 2}]

5. end

DETAIL ED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Router(config)# interface BRI 0

Specifies the interface and enters interface configuration mode.

Step 4

isdn v110 only [databits {5 | 7 | 8}] [parity {even | mark | none | odd | space}] [stopbits {1 | 1.5 | 2}]

Router(config-if)# isdn v110 only databits 8 parity none stopbits 1

Selectively accepts incoming V.110 calls based on data bit, parity, and stop bit modem communication settings.

Step 5

end

Router(config)# end

Exits global configuration mode.

Disabling V.110 Padding

Perform this task to disable V.110 padding. In networks with devices such as terminal adapters (TAs) and global system for mobile communication (GSM) handsets that do not fully conform to the V.110 modem standard, you will need to disable V.110 padding.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. no isdn v110 padding

5. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Router(config)# interface BRI 0

Specifies the interface and enters interface configuration mode.

Step 4

no isdn v110 padding

Router(config-if)# no isdn v110 padding

Disables the padded modem speed report required by the V.110 modem standard.

Step 5

end

Router(config)# end

Exits interface configuration mode and returns to global configuration mode.

Configuring ISDN Semipermanent Connections

German networks allow semipermanent connections between customer routers with BRI interfaces and the 1TR6 basic rate switches in the exchange. Australian networks allow semipermanent connections between ISDN PRI interfaces and the TS-014 primary rate switches in the exchange. Semipermanent connections are better priced than leased lines.

Configuring BRI interfaces for semipermanent connection requires only a keyword that indicates the semipermanent connections when you are setting up network addressing as described in the previous section of this module.

To configure a BRI for semipermanent connections, follow this procedure:

Step 1 Set up the ISDN lines and ports as described in the sections “Configuring the ISDN BRI Switch” and “Specifying Interface Characteristics for an ISDN BRI”. For ISDN PRI, see the section “How to Configure ISDN PRI” in the module “Configuring ISDN PRI”.

Step 2 Configure DDR on a selected interface, as described in the “Dial-on-Demand Routing Configuration” part of this publication.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. dialer map protocol next-hop-address name hostname spc [speed 56 | 64] [broadcast] dial-string[:isdn-subaddress]

5. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Router(config)# interface BRI 0

Specifies the interface and begins interface configuration mode.

Step 4

dialer map protocol next-hop-address name hostname spc [speed 56 | 64] [broadcast] dial-string[:isdn-subaddress]

Router(config-if)# dialer map ip

172.19.1.8 name user1 spc 64 [broadcast] zzz 14155550134

Defines the remote recipient’s protocol address, host name, and dialing string; indicates semipermanent connections; optionally, provides the ISDN subaddress; and sets the dialer speed to 56 or 64 kb/s, as needed.

Step 5

end

Router(config)# end

Exits interface configuration mode and returns to global configuration mode.

Configuring ISDN BRI for Leased-Line Service

To configure ISDN BRI for leased-line service, perform the tasks in one of the following sections as needed and available:

- Configuring Leased-Line Service at Normal Speeds (Available in Japan and Germany)

- Configuring Leased-Line Service at 128 Kb/s (Available only in Japan)

Note When an ISDN BRI interface is configured for access over leased lines, it is no longer a dialer interface, and signaling over the D channel no longer applies. Although the interface is called interface bri n, it is configured as a synchronous serial interface having the default High-Level Data Link (HDLC) encapsulation. However, the Cisco IOS commands that set the physical characteristics of a serial interface (such as the pulse time) do not apply to this interface.

Configuring Leased-Line Service at Normal Speeds

This service is offered in Japan and Germany and no call setup or teardown is involved. Data is placed on the ISDN interface similar to the way data is placed on a leased line connected to a serial port.

The isdn leased-line bri command enable the router to configure the BRI to use the ISDN connection as a leased-line service. The no isdn leased-line bri command removes the leased-line configuration from a specified ISDN BRI interface.

SUMMARY STEPS

1. enable

2. configure terminal

3. isdn leased-line bri number number [128 | 144]

4. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

isdn leased-line bri number number [128 | 144]

Router(config)# isdn leased-line BRI 0 123 [128 | 144]

Specifies the combined B1 and B2 channels leased lines.

Step 4

end

Router(config)# end

Exits global configuration mode.

Configuring Leased-Line Service at 128 Kb/s

The Cisco IOS software supports leased-line service at 128 kb/s via ISDN BRI. This service combines two B channels into a single pipe. This feature requires one or more ISDN BRI hardware interfaces that support channel aggregation, and service provider support for ISDN channel aggregation at 128 kb/s. When this software first became available, service providers offered support for ISDN channel aggregation at 128 kb/s only in Japan.

The isdn leased-line bri commands enable the router to configure the BRI to use the ISDN connection as a leased-line service at 128kb/s.

Note This feature is not supported on the Cisco 2500 series router because its BRI hardware does not support channel aggregation.

The no isdn leased-line bri command command removes the leased-line configuration from a specified ISDN BRI interface.

SUMMARY STEPS

1. enable

2. configure terminal

3. isdn leased-line bri number 128

4. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

isdn leased-line bri number 128

Router(config)# isdn leased-line BRI 0 128

Configures a specified BRI for access over leased lines.

Step 4

end

Router(config)# end

To complete the configuration of the interface, see the module “Configure Synchronous Serial Ports” in this module.

Monitoring and Maintaining ISDN Interfaces

The show interfaces, show controllers, show isdn, and the show dialer interface bri commands enable the router to monitor and maintain ISDN interfaces, use the following commands in EXEC mode as needed:

SUMMARY STEPS

1. enable

2. show interfaces bri number

3. show controllers bri number

4. show isdn {active | history | memory | status | timers}

5. show dialer interface bri number

6. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

show interfaces bri number

Cisco 7200 series routers only

show interfaces bri slot/port

show interfaces bri 0

Cisco 7200 series routers only

Router> show interfaces bri slot/port

Displays information about the physical attributes of the ISDN BRI B and D channels.

Step 3

show controllers bri number

Cisco 7200 series routers only

show controllers bri slot/port

Router> show controllers bri 0

Cisco 7200 series routers only

Router> show controllers bri 0

Displays protocol information about the ISDN B and D channels.

Step 4

show isdn {active | history | memory | status | timers}

Router> show isdn active

Displays information about calls, history, memory, status, and Layer 2 and Layer 3 timers.

Step 5

show dialer interface bri number

Router> show dialer interface bri 0

Obtains general diagnostic information about the specified interface.

Step 6

end

Router(config)# end

Exits global configuration mode.

Troubleshooting ISDN Interfaces

The following commands can help verify the ISDN configuration of the router:

- show controllers bri number —Checks Layer 1 (physical layer) of the BRI.

- debug q921 —Checks Layer 2 (data link layer).

- debug isdn events —Checks the network layer.

- debug q931—Checks the network layer.

- debug dialer—Checks the network layer.

- show dialer—Checks the network layer.

Refer to the Cisco IOS Debug Command Reference for more information about the debug commands.

Configuration Examples for Configuring ISDN BRI

This section provides the following ISDN BRI configuration examples:

- Example: Configuring a Global ISDN and BRI Interface Switch Type

- Example: Configuring a BRI Connected to a PBX

- Example: Configuring Multilink PPP on a BRI Interface

- Example: Configuring Dialer Rotary Groups

- Example: Configuring Predictor Compression

- Example: Configuring Multilink PPP and Compression

- Example: Configuring Voice over ISDN

- Example: DNIS-plus-ISDN-Subaddress Binding

- Example: Screening Incoming V.110 Modem Calls

- Example: ISDN BRI Leased-Line Configuration

Example: Configuring a Global ISDN and BRI Interface Switch Type

The following example shows to configure a global National ISDN switch type (keyword basic-ni) and an interface-level NET3 ISDN switch type (keyword basic-net3). The basic-net3 keyword is applied to BRI interface 0 and overrides the global switch setting.

isdn switch-type basic-ni

!

interface bri 0

isdn switch-type basic-net3

Example: Configuring a BRI Connected to a PBX

The following example provides a simple partial configuration of a BRI interface that is connected to a PBX. This interface is connected to a switch that uses SPID numbers.

interface bri 0

description connected to pbx line 61885

ip address 10.1.1.3 255.255.255.0

encapsulation ppp

isdn spid1 123

dialer map ip 10.1.1.1 name mutter 61886

dialer map ip 10.1.1.2 name rudder 61884

dialer map ip 10.1.1.4 name flutter 61888

dialer-group 1

no fair-queue

ppp authentication chap

Example: Configuring Multilink PPP on a BRI Interface

The following example shows how to enable Multilink PPP on BRI interface 0:

interface bri 0

description Enables PPP Multilink on BRI 0

ip address 10.1.1.1 255.255.255.0

encapsulation ppp

dialer map ip 10.1.1.2 name coaster 14195291357

dialer map ip 10.1.1.3 name roaster speed 56 14098759854

ppp authentication chap

ppp multilink

dialer-group 1

Example: Configuring Dialer Rotary Groups

interface bri 0

description Enables predictor compression on BRI 0

ip address 10.1.1.1 255.255.255.0

encapsulation ppp

dialer map ip 10.1.1.2 name bon 14195291357

compress predictor

ppp authentication chap

dialer-group 1

The following example shows how to enable stacker compression on BRI interface 0:

interface bri 0

description Enables stac compression on BRI 0

ip address 10.1.1.1 255.255.255.0

encapsulation ppp

dialer map ip 10.1.1.2 name malcom 14195291357

compress stac

ppp authentication chap

dialer-group 1

Example: Configuring Multilink PPP and Compression

The following example shows how to enable Multilink PPP and stacker compression on BRI interface 0:

interface bri 0

description Enables PPP Multilink and stac compression on BRI 0

ip address 10.1.1.1 255.255.255.0

encapsulation ppp

dialer map ip 10.1.1.2 name rudd 14195291357

ppp authentication chap

compress stac

ppp multilink

dialer-group 1

Example: Configuring Voice over ISDN

The following example shows how to allow incoming voice calls to be answered on BRI interface 0:

interface bri 0

description Allows incoming voice calls to be answered on BRI 0

ip address 10.1.1.1 255.255.255.0

encapsulation ppp

isdn incoming-voice data

dialer map ip 10.1.1.2 name starstruck 14038182344

ppp authentication chap

dialer-group 1

Example: DNIS-plus-ISDN-Subaddress Binding

Example: Screening Incoming V.110 Modem Calls

The following example shows to filter out all V.110 modem calls except those with communication settings of 8 data bits, no parity bit, and 1 stop bit:

interface serial 0:23

isdn v110 only databits 8 parity none stopbits 1

Example: ISDN BRI Leased-Line Configuration

The following example shows how to configure BRI interface 0 for leased-line access at 128 kb/s. Because of the leased-line—not dialed—environment configuration of ISDN called and calling numbers are not needed and not used. BRI interface 0 is henceforth treated as a synchronous serial interface, with the default HDLC encapsulation.

isdn leased-line 128

Additional References

Related Documents

Related Topic

Document Title

Modem configuration commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples

Cisco IOS Dial Technologies Command Reference

Modem configuration and management

Cisco IOS Dial Technologies Configuration Guide

Standards

Standard

Title

None

—

MIBs

MIB

MIBs Link

No new or modified MIBs are supported, and support for existing MIBs has not been modified.

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

RFCs

RFC

Title

No new or modified RFCs are supported, and support for existing RFCs has not been modified.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for Configuring ISDN BRI

Table 4 lists the release history for this feature.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Note Table 4 lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Feature Name

Releases

Feature Information

National ISDN Switch Types for BRI and PRI Interfaces

11.3(3)T

12.0(1)

12.0(1)T

12.1(14)

12.1(3)T

12.2(11)YT

12.2(11)YV

12.2(13)T

12.2(15)T

12.2(2)T

12.2(8)T

12.5

12.4T

12.2SR

15.1.(1)S

The National ISDN Switch Types for Basic Rate and Primary Rate Interfaces feature introduces changes to ISDN switch types for Primary Rate Interfaces (PRI) and BRI.

These switches provide the ability to connect to multiple ISDN switch types (BRI and PRI) and the NI2 switch type.

The following commands were introduced or modified:

dialer called, dialer map, isdn calling-number, isdn disconnect-cause, isdn fast-rollover-delay, isdn leased-line type, isdn not-end-to-end, isdn sending complete, isdn v10 only, no isdn v10 padding, show controllers show isdn, show dialer interface bri, show interfaces.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2003–2010 Cisco Systems, Inc. All rights reserved.

Leased and Switched BRI Interfaces for

ETSI NET3

Feature History

Release

Modification

12.2(4)T

This feature was introduced on the Cisco 800 series routers.

This document describes the Leased and Switched BRI Interfaces for ETSI NET3 feature. It includes the following sections:

- Feature Overview

- Supported Platforms

- Supported Standards, MIBs, and RFCs

- Prerequisites

- Configuration Tasks

- Monitoring and Maintaining Leased and Switched BRI Interfaces for ETSI NET3

- Configuration Examples

- Command Reference

Feature Overview

1. In most BRI configurations, both B channels of a leased-line service are used as point-to-point leased lines with the D channel disabled. Data transmission over the B channels is no different than data transmission over point-to-point leased lines.

2. A new feature available in Cisco IOS Release 12.2(4)T, Leased and Switched BRI Interfaces for ETSI NET3, allows one BRI B channel on a European Telecommunications Standards Institute (ETSI) NET3 switch to be configured as a leased line, and the second B channel to be configured as a standard ISDN or dial interface and used as a switched channel to the Public Switched Telephone Network (PSTN). When the Leased and Switched BRI Interfaces for ETSI NET3 feature is configured, one B channel functions as a point-to-point 64-kbps leased line and the other B channel functions as a circuit-switched channel using the D channel to provide the signaling features available for the ETSI NET3 signaling protocol.

Benefits

The Leased and Switched BRI Interfaces for ETSI NET3 feature allows Internet service providers to split one ISDN line into a leased-line interface and a dialer interface, thereby increasing connection capability without increasing cost.

Restrictions

The following restrictions apply to the Leased and Switched BRI Interfaces for ETSI NET3 feature:

- Only the ETSI NET3 signaling protocol is supported at a line speed of 64 kbps.

- Only one ISDN call can be active at any time, and the call must verify that the leased line is not used to bring up a second call.

- The ETSI NET3 switch cannot be configured for a leased line when the U interface is used instead of the S/T interface; doing so prevents the line protocol from coming up.

Related Documents

- Cisco IOS Dial Technologies Command Reference , Release 12.2

- Cisco IOS Dial Technologies Configuration Guide , “ISDN Configuration” part, Release 12.2

Supported Platforms

- Cisco 800 series

Platform Support Through Feature Navigator

Cisco IOS software is packaged in feature sets that support specific platforms. To get updated information regarding platform support for this feature, access Feature Navigator. Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.

Feature Navigator is a web-based tool that enables you to quickly determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image.

To access Feature Navigator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions at http://www.cisco.com/register.

Feature Navigator is updated when major Cisco IOS software releases and technology releases occur. As of May 2001, Feature Navigator supports M, T, E, S, and ST releases. You can access Feature Navigator at the following URL:

http://www.cisco.com/go/fn

Supported Standards, MIBs, and RFCs

Standards

None

MIBs

The fillin_isdnBearerEntry() – isdnBearerTable manipulation MIB function is supported. See the “RFCs” section for more information.

To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

RFCs

- RFC 2127, ISDN Management Information Base using SMIv2

RFC 2127 states that the following be reported for the leased line B channel: The isdnBearerTable MIB entry for the leased line B channel will need to be altered, specifically the value of isdnBearerChannelType MIB will be set to leased(2). This alteration involves a function in isdn/sr_ietf_isdmib.c, namely the fillin_isdnBearerEntry() — isdnBearerTable manipulation MIB function.

- RFC 1573, Evolution of the Interfaces Group of MIB-II

RFC 1573 makes no explicit mention of changes to the ifEntry for a B channel set to leased line. It is proposed that the ifAdminStatus and ifOperStatus functions remain in the UP(1) state.

Prerequisites

Before starting the configuration tasks in this document, review the chapter “Configuring ISDN BRI” and the section “Configuring ISDN BRI for Leased-Line Service,” for more complete details on configuring a BRI. This chapter is in the part “ISDN Configuration” in the Cisco IOS Dial Technologies Configuration Guide, Release 12.2.

Configuration Tasks

See the following sections for configuration tasks for the Leased and Switched BRI Interfaces for ETSI NET3 feature. Each task in the list is identified as either required or optional:

- Configuring Leased and Switched BRI Interfaces for ETSI NET3 (required)

- Verifying Leased and Switched BRI Interfaces for ETSI NET3 (optional)

Configuring Leased and Switched BRI Interfaces for ETSI NET3

Command

Purpose

Step 1

Router(config)# isdn switch-type basic-net3

Configures the ETSI NET3 BRI switch type.

Step 2

Router(config)# isdn leased-line brinumber/number {b1 | b2}

Splits a line for both ISDN and 64-kbps leased-line service.

Verifying Leased and Switched BRI Interfaces for ETSI NET3

Note In the following verification procedure, BRI channel B1(the BRI0:1 interface) is configured for leased-line service and channel B2 (the BRI0:2 interface) is configured for ISDN.

To verify that each BRI channel is configured correctly, perform the following steps:

Step 1 Enter the show isdn status EXEC command and check the value in The Free Channel Mask field to verify that only one channel has been allocated for ISDN. The Free Channel Mask field displays 0x80000000 when there is an active call. If no call is active, The Free Channel Mask field displays 0x80000001 and 0x80000002 for the B1 and B2 leased line configurations, respectively.

Router# show isdn status

Global ISDN Switchtype = basic-net3

ISDN BRI0 interface

dsl 0, interface ISDN Switchtype = basic-net3

Layer 1 Status:

ACTIVE

Layer 2 Status:

TEI = 124, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED

I_Queue_Len 0, UI_Queue_Len 0

Layer 3 Status:

1 Active Layer 3 Call(s)

CCB:callid=8001, sapi=0, ces=1, B-chan=2, calltype=DATA

Active dsl 0 CCBs = 1

The Free Channel Mask: 0x80000000

Total Allocated ISDN CCBs = 1

Step 2 Enter the show dialer EXEC command to display dialer interface statistics. Check that there is no entry for the BRI0:1 interface in the display:

Router# show dialer

BRI0 - dialer type = ISDN

Dial String Successes Failures Last DNIS Last status

0 incoming call(s) have been screened.

0 incoming call(s) rejected for callback.

BRI0:2 - dialer type = ISDN

Idle timer (120 secs), Fast idle timer (20 secs)

Wait for carrier (30 secs), Re-enable (15 secs)

Dialer state is idle

Di1 - dialer type = DIALER PROFILE

Idle timer (6000 secs), Fast idle timer (20 secs)

Wait for carrier (30 secs), Re-enable (15 secs)

Dialer state is idle

Number of active calls = 0

Dial String Successes Failures Last DNIS Last status

5552000 0 0 never - Default

Troubleshooting Tips

Command

Purpose

Router# show controllers bri number

Checks Layer 1 of the BRI.

Router# debug q921

Checks Layer 2 of the BRI.

Router# debug dialer

Checks dialer events on the BRI.

Router# debug isdn events

Checks call control events on the BRI.

Router# debug q931

Checks Layer 3 of the BRI.

Refer to the Cisco IOS Debug Command Reference for more information about the debug commands.

Monitoring and Maintaining Leased and Switched BRI Interfaces for ETSI NET3

Command

Purpose

Router# show isdn status

Displays Layer 1, Layer 2, and Layer 3 status of the D channel and channel mask information.

Router# show interfaces bri x:y status

Displays status of the ISDN BRI channel configured as either a leased line or dialer B-channel interface.

Router# show dialer

Displays status of the ISDN BRI channel configured as a dialer interface.

Configuration Examples

This section provides an example of how to configure the Leased and Switched BRI Interfaces for ETSI NET3 feature.

Leased and Switched BRI Interfaces for ETSI NET3 Example

- isdn leased-line bri

Glossary

European Telecommunications Standards Institute—See ETSI.

ETSI—European Telecommunications Standards Institute. Organization created by European Post, Telephone, and Telegraph (PTT) groups and the European Community (EC) to propose telecommunications standards for Europe.

leased line—Transmission line reserved by a communications carrier for the private use of a customer.

switched—General term applied to an electronic or mechanical device that allows a connection to be established as necessary and terminated when there is no longer a session to support.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.

© 2001-2008 Cisco Systems, Inc. All rights reserved.

ISDN BCAC and Round-Robin Channel Selection Enhancements

The ISDN BCAC and Round-Robin Channel Selection Enhancements feature allows more dynamic control of the ISDN B channels by providing additional B-Channel Availability Control (BCAC) functionality for configuring message signaling, and an enhanced channel selection scheme that adds round-robin configuration to the existing ascending and descending channel selection schemes already available.

Feature Specifications for the ISDN BCAC Enhancements

Feature History

Release

Modification

12.3(1)

This feature was introduced.

Supported Platforms

Cisco AS5300, Cisco AS5350, Cisco AS5400, Cisco AS5800, Cisco AS5850, Cisco 2600 series, Cisco 3640, Cisco 3660

Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

Contents

- Prerequisites for ISDN BCAC Enhancements

- Information About the ISDN BCAC and Round-Robin Channel Selection Enhancements

- How to Configure the ISDN Enhancements

- Configuration Examples for ISDN BCAC and Round-Robin Channel Selection Enhancements

- Additional References

- Command Reference

Prerequisites for ISDN BCAC Enhancements

You need to need to be familiar with the BCAC service message signaling procedure and configuring ISDN PRI before configuring the commands described in this document. See the “Standards” section for a list of references.

Information About the ISDN BCAC and Round-Robin Channel Selection Enhancements

The following functionality is introduced in the ISDN BCAC and Round-Robin Channel Selection Enhancements:

- BCAC Enhancements

- Round-Robin Selection Scheme for ISDN B Channels

- Logging of ISDN Events

- Additional ISDN Switch Types Supported for Network Emulation

BCAC Enhancements

BCAC is a service message signaling procedure used to control the availability of ISDN B channels. BCAC provides a coordinated capability between both ends of a PRI to simultaneously preclude selection of specified B channels for outgoing calls, and reject calls (if channel negotiation is employed, calls may go on another channel) for those same channels. The basic BCAC functionality for the handling of SERV and SERV ACK messages already exists on Cisco routers. In Cisco IOS Release 12.3(1), the software has been enhanced with the following BCAC functionality:

- Processing of SERV and SERV ACK messages. Even though these messages are already handled in the Cisco IOS software, their processing has been enhanced to more closely align with the behavior described in the standards.

- Provides a mechanism to allow the retransmission of SERV messages.

- Handles SERV message collision cases.

- Provides service status audits for various audit triggers.

- Provides an option that when set triggers the exchange of service messages on all channels of the interface when the router is rebooted and when the signaling link comes up.

- Provides a mechanism so that if there is a flood of service messages that need to be sent, the service messages can be throttled to avoid losing them.

- Initializes B-channel service status upon provisioning.

Round-Robin Selection Scheme for ISDN B Channels

ISDN enhancements introduced in Cisco IOS Release 12.3(1) enable you to select a B channel on a PRI or a Non-Facility Associated Signaling (NFAS) interface in a round-robin fashion. This option is in addition to the ascending or descending channel selection schemes already available.

Logging of ISDN Events

ISDN enhancements introduced in Cisco IOS Release 12.3(1) support syslog logging of the following ISDN events:

- ISDN Layer 2 Up and Down events at severity 3.

- ISDN SERV, SERV ACK, Restart, Restart Ack, and Status Enq messages at severity 4.

- ISDN SERV status audit messages for various triggers at different severities.

Additional ISDN Switch Types Supported for Network Emulation

ISDN enhancements introduced in Cisco IOS Release 12.3(1) extend network emulation capability to the Lucent 4ESS, 5ESS, and Nortel DMS-100 ISDN switch types. These switch types can be configured as network, but no additional changes were made and not all network-side features are supported.

How to Configure the ISDN Enhancements

This section contains the following procedures. Each procedure is optional and depends upon the settings required for your network.

- Configuring BCAC Service Audit Triggers (optional)

- Configuring BCAC Service State Triggers (optional)

- Configuring BCAC Message Retransmission (optional)

- Configuring B-Channel Selection Order (optional)

- Configuring ISDN Syslog Messages (optional)

Configuring BCAC Service Audit Triggers

Perform this task to configure BCAC service audit triggers:

SUMMARY STEPS

1. enable

2. configure terminal

3. interface serial port:channel

4. isdn bcac service audit

5. isdn bcac service audit trigger number

6. isdn bcac service audit interface

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface serial port:channel

Router(config)# interface serial 2:23

Enters interface configuration mode on the specified serial port and channel.

Step 4

isdn bcac service audit

Router(config-if)# isdn bcac service audit

Enables BCAC service audits.

Step 5

isdn bcac service audit trigger number

Router(config-if)# isdn bcac service audit trigger 2

Enables individual BCAC service audit triggers.

Step 6

isdn bcac service audit interface

Router(config-if)# isdn bcac service audit interface

Specifies that BCAC service audits need to be triggered on the entire interface.

Examples

The following example shows how to enable service audits on serial interface 4:23:

interface serial 4:23

isdn bcac service audit

The following example shows how to configure service audits on the entire interface:

interface serial 4:23

isdn bcac service audit interface

Configuring BCAC Service State Triggers

Perform this task to configure BCAC service state triggers:

SUMMARY STEPS

1. enable

2. configure terminal

3. interface serial port:channel

4. isdn bcac service update provision

5. isdn bcac service update linkup

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface serial port:channel

Router(config)# interface serial 2:23

Enters interface configuration mode on the specified serial port and channel.

Step 4

isdn bcac service update provision

Router(config-if)# isdn bcac service update provision

Enables BCAC service status functionality for provisioning the B channels.

Step 5

isdn bcac service update linkup

Router(config-if)# isdn bcac service update linkup

Triggers updates of the BCAC service states between peer nodes through exchange of SERV and SERV ACK messages.

Examples

The following example shows how to enable the SERV status message for provisioning the B channels on serial interface 4:23:

interface serial 4:23

isdn bcac service update provision

The following example shows how to trigger service state updates on serial interface 4:23:

interface serial 4:23

isdn bcac service update linkup

Configuring BCAC Message Retransmission

Perform this task to configure retransmission of BCAC service messages:

SUMMARY STEPS

1. enable

2. configure terminal

3. interface serial port:channel

4. isdn bcac service timer timer-value

5. isdn bcac service retry max retries

6. isdn bcac service retry in-serv-on-fail

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface serial port:channel

Router(config)# interface serial 2:23

Enters interface configuration mode on the specified serial port and channel.

Step 4

isdn bcac service timer timer-value

Router(config-if)# isdn bcac service timer 600

Changes the value of the BCAC T3M1 or T323 service message timer.

- Valid range is from 500 to 120000 ms, and the default is 120000 ms.

Step 5

isdn bcac service retry max retries

Router(config-if)# isdn bcac service retry max retries

Specifies the maximum number of times a BCAC service message can be retransmitted when unacknowledged.

- The default is 2 attempts, and you can enter a number from 0 to 127.

Step 6

isdn bcac service retry in-serv-on-fail

Router(config-if)# isdn bcac service retry in-serv-on-fail

Specifies that the BCAC service state of the channel needs to be changed to In-Service, because no acknowledgment message was received.

Examples

The following example shows how to configure an option whereby, on service message exchange failure, the service state of the concerned channel or channels will be set to In-Service:

interface serial 2:23

isdn bcac service retry in-serv-on-fail

The following example shows how to change the service timers to 600 ms on serial interface 2:23:

interface serial 2:23

isdn bcac service timer 600

Configuring B-Channel Selection Order

Perform this task to configure selection order of the ISDN B channels:

SUMMARY STEPS

1. enable

2. configure terminal

3. interface serial port:channel

4. isdn bchan-number-order {ascending | descending} [round-robin]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface serial port:channel

Router(config)# interface serial 2:23

Enters interface configuration mode on the specified serial port and channel.

Step 4

isdn bchan-number-order {ascending | descending} [round-robin]

Router(config-if)# isdn bchan-number-order ascending round-robin

Configures an ISDN PRI interface to make outgoing call selection in ascending or descending order.

- The optional round-robin keyword adds round-robin selection functionality to the selection order.

Examples

The following example configures the outgoing B channel selection order on a PRI interface to be round-robin in ascending order:

interface serial 5:10

isdn bchan-number-order ascending round-robin

Configuring ISDN Syslog Messages

Perform this task to configure logging of ISDN syslog messages:

SUMMARY STEPS

1. enable

2. configure terminal

3. isdn logging

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

isdn logging

Router(config)# isdn logging

Enables logging of ISDN syslog messages.

Examples

The following example shows how to configure ISDN syslog logging:

isdn logging

Configuration Examples for ISDN BCAC and Round-Robin Channel Selection Enhancements

See the examples following each task in the preceding sections, for ideas about how the ISDN CBAC enhancements and other new ISDN features can be introduced into your network.

Additional References

For additional information related to the ISDN enhancements, see the following sections:

- Related Documents

- Standards

- MIBs

- RFCs

- Technical Assistance

Related Documents

Related Topic

Document Title

ISDN PRI configuration

Refer to the “Configuring ISDN PRI” chapter in the “Signaling Configuration” part of the Cisco IOS Dial Technologies Configuration Guide, Release 12.3.

ISDN PRI configuration commands

Cisco IOS Dial Technologies Command Reference, Release 12.3.

ISDN PRI configuration for voice, video, and fax

Refer to the chapter “Configuring ISDN Interfaces for Voice ” in the Cisco IOS Voice, Video, and Fax Configuration Guide, Release 12.3.

ISDN PRI voice, video, and fax configuration commands

Cisco IOS Voice, Video, and Fax Command Reference, Release 12.3

Standards

Standards 1

Title

AT&T PRI

Technical Report 41459–AT&T ISDN Primary Rate Interface and Special Application Specification; “User Network Interface Description,” 1999.

National ISDN Council (NIC) PRI

SR (Special Report)-NWT-002343–ISDN Primary Rate Interface Generic Guidelines for Customer Premises Equipment, June 1993.

SR-3887–National ISDN Primary Rate Interface Customer Premises Equipment Generic Guidelines, 1996.

Nortel PRI

NIS (Network Interface Specification)-A211-1–DMS100 ISDN Primary Rate Network User Interface, 1993.

1.Not all supported standards are listed.

MIBs

MIBs

MIBs Link

None

To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

RFCs

RFCs

Title

None

—

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

Command Reference

The following commands are introduced or modified in the feature or features documented in this module. For information about these commands, see the Cisco IOS Dial Technologies Command Reference at http://www.cisco.com/en/US/docs/ios/dial/command/reference/dia_book.html. For information about all Cisco IOS commands, go to the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or to the Cisco IOS Master Commands List.

New Commands

- isdn bcac service audit

- isdn bcac service audit interface

- isdn bcac service audit trigger

- isdn bcac service retry in-serv-on-fail

- isdn bcac service retry max

- isdn bcac service timer

- isdn bcac service update linkup

- isdn bcac service update provision

- isdn logging

Modified Commands

- isdn bchan-number-order

- isdn protocol-emulate (dial)

Glossary

PBX—private branch exchange.

RESTART—restart message.

RESTART ACK—restart acknowledge message.

STATUS ENQ—status enquiry message.

SERV—service message.

SERV ACK—service acknowledge message.

Note Refer to the Internetworking Terms and Acronyms for terms not included in this glossary.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2001–2009 Cisco Systems, Inc. All rights reserved

Configuring ISDN Special Signaling

This chapter describes features that either depend on special signaling services offered by an ISDN network service provider or overcome an inability to deliver certain signals. It describes these features in the following main sections:

- How to Configure ISDN Special Signaling

- Troubleshooting ISDN Special Signaling

- Configuration Examples for ISDN Special Signaling

For an overview of ISDN PRI, see the section “ISDN Service” in the “Overview of Dial Interfaces, Controllers, and Lines” chapter, and the section “ISDN Overview” in the Configuring ISDN BRI chapter.

To identify the hardware platform or software image information associated with a feature, use the Feature Navigator on Cisco.com to search for information about the feature or refer to the software release notes for a specific release. For more information, see the “Identifying Supported Platforms” section in the “Using Cisco IOS Software” chapter.

For a complete description of the ISDN signaling commands in this chapter, refer to the Cisco IOS Dial Technologies Command Reference. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

How to Configure ISDN Special Signaling

To configure special signaling features of ISDN, perform the tasks in the following sections; all tasks are optional:

- Configuring ISDN AOC (Optional)

- Configuring NFAS on PRI Groups (Optional)

- Enabling an ISDN PRI to Take PIAFS Calls on MICA Modems (Optional)

- Configuring Automatic Detection of Encapsulation Type (Optional)

- Configuring Encapsulation for Combinet Compatibility (Optional)

See the section “Configuration Examples for ISDN Special Signaling” at the end of this chapter for examples of these signaling features. See the “Troubleshooting ISDN Special Signaling” section later in this chapter for help in troubleshooting ISDN signaling features.

Configuring ISDN AOC

ISDN Advice of Charge (AOC) allows users to obtain charging information for all calls during the call (AOC-D) or at the end of the call (AOC-E) or both.

Users must have subscribed through their local ISDN network to receive the AOC information from the switch. No router configuration changes are required to retrieve this call charging information.

The ISDN AOC feature also supports, for the AOC-D service, an optional configurable short-hold mode that provides a dynamic idle timeout by measuring the call charging period, based on the frequency of the AOC-D or the AOC-E message from the network. The short-hold mode allows users to track call costs and to control and possibly reduce tariff charges. The short-hold mode idle time will do the following:

- Disconnect a call just before the beginning of a new charging period if the call has been idle for at least the configured minimum idle time.

- Maintain the call to the end of the current charging period past the configured idle timeout if the time left in the charging period is longer.

Incoming calls are disconnected using the static dialer idle timeout value.

The AOC-D and AOC-E messages are part of the Facility Information Element (IE) message. Its contents can be verified with the debug q931 command. Call accounting information from AOC-D and AOC-E messages is stored in Simple Network Management Protocol (SNMP) MIB objects.

ISDN AOC is provided for ISDN PRI NET5 and ISDN BRI NET3 switch types only. AOC information at call setup is not supported.

Configuring Short-Hold Mode

No configuration is required to enable ISDN AOC. However, you can configure the optional short-hold minimum idle timeout period for outgoing calls; the default minimum idle timeout is

120 seconds. If the short-hold option is not configured, the router default is to use the static dialer idle timeout. If the short-hold idle timeout has been configured but no charging information is available from the network, the static dialer idle timeout applies.

To configure an ISDN interface and provide the AOC short-hold mode option on an ISDN interface, perform the following steps:

Step 1 Configure the ISDN BRI or PRI interface, as described in the chapter Configuring ISDN BRI or the section “How to Configure ISDN PRI” in the chapter “Configuring ISDN PRI” later in this publication, using the relevant keyword in the isdn switch-type command:

- BRI interface— basic-net3

- PRI interface— primary-net5

Step 2 Configure dialer profiles or legacy dial-on-demand routing (DDR) for outgoing calls, as described in the chapters in the “Dial-on-Demand Routing” part of this publication, making sure to do the following:

- Configure the static line-idle timeout to be used for incoming calls.

- For each destination, use the dialer map command with the class keyword (legacy DDR) or a dialer string class command (dialer profiles) to identify the dialer map class to be used for outgoing calls to the destination.

Step 3 Configure each specified dialer map class, providing a dialer idle timeout, or ISDN short-hold timeout, or both for outgoing calls, as described in this chapter.

Command

Purpose

Step 1

Router(config)# map-class dialer classname

Specifies the dialer map class and begins map class configuration mode.

Step 2

Router(config-map-class)# dialer idle-timeout seconds

(Optional) Specifies a static idle timeout for the map class to override the static line-idle timeout configured on the BRI interface.

Step 3

Router(config-map-class)# dialer isdn short-hold seconds

Specifies a dialer ISDN short-hold timeout for the map class.

Monitoring ISDN AOC Call Information

Command

Purpose

Router> show isdn {active [dsl | serial-number] | history [dsl | serial-number ] | memory | nfas group group-number | service [dsl | serial-number] | status [dsl | serial-number] | timers [dsl | serial-number]}

Displays information about active calls, call history, memory, nfas group, service or status of PRI channels, or Layer 2 or Layer 3 timers. The history keyword displays AOC charging time units used during the call and indicates whether the AOC information is provided during calls or at the end of calls.

(The service keyword is available for PRI only.)

Configuring NFAS on PRI Groups

ISDN Non-Facility Associated Signaling (NFAS) allows a single D channel to control multiple PRI interfaces. A backup D channel can also be configured for use when the primary NFAS D channel fails.

Use of a single D channel to control multiple PRI interfaces can free one B channel on each interface to carry other traffic.

Any hard failure causes a switchover to the backup D channel and currently connected calls remain connected.

Once the channelized T1 controllers are configured for ISDN PRI, only the NFAS primary D channel must be configured; its configuration is distributed to all the members of the associated NFAS group.

ISDN NFAS Prerequisites

Table 1 ISDN Switch Types and NFAS Support

Switch Type

Keyword

NFAS Support

Lucent 4ESS Custom NFAS

primary-4ess

Yes

Lucent 5ESS Custom NFAS

primary-5ess

No (use National)

Nortel DMS Custom NFAS

primary-dms

Yes

NTT Custom NFAS

primary-ntt

Yes

National

primary-ni

Yes

Other switch types

—

No (use National)

Note On the Nortel (Northern Telecom) DMS-100 switch, when a single D channel is shared, multiple PRI interfaces may be configured in a single trunk group. The additional use of alternate route indexing, which is a feature of the DMS-100 switch, provides a rotary from one trunk group to another. This feature enables the capability of building large trunk groups in a public switched network.

The ISDN switch must be provisioned for NFAS. The primary and backup D channels should be configured on separate T1 controllers. The primary, backup, and B-channel members on the respective controllers should be the same as that configured on the router and ISDN switch. The interface ID assigned to the controllers must match that of the ISDN switch.

ISDN NFAS Configuration Task List

To configure NFAS on channelized T1 controllers configured for ISDN, perform the tasks in the following section: Configuring NFAS on PRI Groups (required).

You can also disable a channel or interface, if necessary, and monitor NFAS groups and ISDN service. To do so, perform the tasks in the following sections:

- Configuring NTT PRI NFAS (Optional)

- Disabling a Channel or Interface (Optional)

- Monitoring NFAS Groups (Optional)

- Monitoring ISDN Service (Optional)

See the section “NFAS Primary and Backup D Channels” later in this chapter for ISDN, NFAS, and DDR configuration examples.

Configuring NFAS on PRI Groups

This section documents tasks used to configure NFAS with D channel backup. When configuring NFAS, you use an extended version of the ISDN pri-group command to specify the following values for the associated channelized T1 controllers configured for ISDN:

- The range of PRI time slots to be under the control of the D channel (time slot 24).

- The function to be performed by time slot 24 (primary D channel, backup, or none); the latter specifies its use as a B channel.

- The group identifier number for the interface under control of the D channel.

To configure ISDN NFAS, use the following commands in controller configuration mode:

Command

Purpose

Step 1

Router(config-controller)# pri-group timeslots 1-24 nfas_d primary nfas_interface number nfas_group number

On one channelized T1 controller, configures the NFAS primary D channel.

Step 2

Router(config-controller)# pri-group timeslots 1-24 nfas_d backup nfas_interface number nfas_group number

On a different channelized T1 controller, configures the NFAS backup D channel to be used if the primary D channel fails.

Step 3

Router(config-controller)# pri-group timeslots 1-24 nfas_d none nfas_interface number nfas_group number

(Optional) On other channelized T1 controllers, configures a 24-B-channel interface, if desired.

For an example of configuring three T1 controllers for the NFAS primary D channel, the backup D channel, and 24 B channels, along with the DDR configuration for the PRI interface, see the section “NFAS Primary and Backup D Channels” at the end of this chapter.

When a backup NFAS D channel is configured and the primary NFAS D channel fails, rollover to the backup D channel is automatic and all connected calls stay connected.

If the primary NFAS D channel recovers, the backup NFAS D channel remains active and does not switch over again unless the backup NFAS D channel fails.

Configuring NTT PRI NFAS

Addition of the NTT switch type to the NFAS feature allows its use in geographic areas where NTT switches are available. This feature provides use of a single D channel to control multiple PRI interfaces, and can free one B channel on each interface to carry other traffic.

To configure NTT PRI NFAS, use the procedure described in the “Configuring NFAS on PRI Groups” section. Specify a primary-ntt switch type.

Note You cannot configure a backup D channel for the NTT PRI NFAS feature; it does not support D channel backup.

Verifying NTT PRI NFAS

Step 1 Enter the show isdn status command to learn whether the ISDN PRI switch type was configured correctly:

Router# show isdn status serial 0:23

Global ISDN Switchtype = primary-ntt

ISDN Serial0:23 interface

Step 2 Enter the show isdn nfas group command to display information about members of an NFAS group:

Router# show isdn nfas group 1

ISDN NFAS GROUP 1 ENTRIES:

The primary D is Serial1/0:23.

The NFAS member is Serial2/0:23.

There are 3 total nfas members.

There are 93 total available B channels.

The primary D-channel is DSL 0 in state INITIALIZED.

The current active layer 2 DSL is 0.

Step 3 Enter the show isdn service command to display information about ISDN channels and the service states:

Router# show isdn service

PRI Channel Statistics:

ISDN Se1/0:23, Channel (1-24)

Configured Isdn Interface (dsl) 0

State (0=Idle 1=Propose 2=Busy 3=Reserved 4=Restart 5=Maint)

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3

Channel (1-24) Service (0=Inservice 1=Maint 2=Outofservice)

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

ISDN Se1/1:23, Channel (1-24)

Configured Isdn Interface (dsl) 1

State (0=Idle 1=Propose 2=Busy 3=Reserved 4=Restart 5=Maint)

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Channel (1-24) Service (0=Inservice 1=Maint 2=Outofservice)

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

ISDN Se2/0:23, Channel (1-24)

Configured Isdn Interface (dsl) 2

State (0=Idle 1=Propose 2=Busy 3=Reserved 4=Restart 5=Maint)

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Channel (1-24) Service (0=Inservice 1=Maint 2=Outofservice)

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Disabling a Channel or Interface

Command

Purpose

Router(config-if)# isdn service dsl number b_channel number state state-value

Takes an individual B channel out of service or sets it to a different state.

Router(config-if)# isdn service dsl number b_channel 0 state state-value

Sets the entire PRI to the specified state.

The supported state-values are as follows:

- 0—In service

- 1—Maintenance

- 2—Out of service

When the T1 Controller Is Shut Down

In the event that a controller belonging to an NFAS group is shut down, all active B-channel calls on the controller that is shut down will be cleared (regardless of whether the controller is set to be primary, backup, or none), and one of the following events will occur:

- If the controller that is shut down is configured as the primary and no backup is configured, all active calls on the group are cleared.

- If the controller that is shut down is configured as the primary, and the active (In service) D channel is the primary and a backup is configured, then the active D channel changes to the backup controller.

- If the controller that is shut down is configured as the primary, and the active D channel is the backup, then the active D channel remains as backup controller.

- If the controller that is shut down is configured as the backup, and the active D channel is the backup, then the active D channel changes to the primary controller.

Note The active D channel changeover between primary and backup controllers happens only when one of the link fails and not when the link comes up. The T309 timer is triggered when the changeover takes place.

Monitoring NFAS Groups

Command

Purpose

Router> show isdn nfas group number

Displays information about members of an NFAS group.

Monitoring ISDN Service

To display information about ISDN channel service states, use the following command in EXEC mode:

Command

Purpose

Router> show isdn service

Displays information about ISDN channels and the service states.

Enabling an ISDN PRI to Take PIAFS Calls on MICA Modems

The Personal-Handyphone-System Internet Access Forum Standard (PIAFS) specifications describe a transmission system that uses the PHS 64000 bps/32000 bps unrestricted digital bearer on the Cisco AS5300 universal access server platform.

The PIAFS TA (terminal adapter) module is like a modem or a V.110 module in the following ways:

- Ports will be a pool of resources.

- Calls will use the same call setup Q.931 message.

- Module supports a subset of common AT commands.

- Call setup and teardown are similar.

However, the rate negotiation information will be part of the bearer cap and not the lower-layer compatibility. PIAFS calls will have the user rate as 32000 and 64000; this will be used to distinguish a PIAFS call from a V.110 call. Also, PIAFS will use only up to octets 5a in a call setup message. The data format will default to 8N1 for PIAFS calls.

Command

Purpose

Step 1

Router(config)# interface serial controller:channel

Enters interface configuration mode for a D-channel serial interface.

Step 2

Router(config-if)# isdn piafs-enabled

Enables the PRI to take PIAFS calls on MICA modems.

Step 3

Router(config-if)# exit

Exits interface configuration mode.

Verifying PIAFS

Step 1 Enter the show modem operational-status slot/port command to view PIAFS call information.

Router# show modem op 1/32

Mdm Typ Status Tx/Rx G Duration RTS CTS DCD DTR

1/32 ISDN Conn 64000/64000 0 1d01h x x x x

Modem 1/32, Mica Hex Modem (Managed), Async33, tty33

Firmware Rev: 8.2.0.c

Modem config: Incoming and Outgoing

Protocol: PIAFS, Compression: V.42bis both

Management config: Status polling

RX signals: 0 dBm

Last clearing of "show modem" counters never

2 incoming completes, 0 incoming failures

0 outgoing completes, 0 outgoing failures

0 failed dial attempts, 0 ring no answers, 0 busied outs

0 no dial tones, 0 dial timeouts, 0 watchdog timeouts

0 no carriers, 0 link failures, 0 resets, 0 recover oob

0 recover modem, 0 current fail count

0 protocol timeouts, 0 protocol errors, 0 lost events

0 ready poll timeouts

Configuring Automatic Detection of Encapsulation Type

You can enable a serial or ISDN interface to accept calls and dynamically change the encapsulation in effect on the interface when the remote device does not signal the call type. For example, if an ISDN call does not identify the call type in the lower-layer compatibility fields and is using an encapsulation that is different from the one configured on the interface, the interface can change its encapsulation type dynamically.

This feature enables interoperation with ISDN terminal adapters that use V.120 encapsulation but do not signal V.120 in the call setup message. An ISDN interface that by default answers a call as synchronous serial with PPP encapsulation can change its encapsulation and answer such calls.

Automatic detection is attempted for the first 10 seconds after the link is established or the first 5 packets exchanged over the link, whichever is first.

To enable automatic detection of encapsulation type, use the following command in interface configuration mode:

Command

Purpose

Router(config-if)# autodetect encapsulation encapsulation-type

Enables automatic detection of encapsulation type on the specified interface.

You can specify one or more encapsulations to detect. Cisco IOS software currently supports automatic detection of PPP and V.120 encapsulations.

Configuring Encapsulation for Combinet Compatibility

Historically, Combinet devices supported only the Combinet Proprietary Protocol (CPP) for negotiating connections over ISDN B channels. To enable Cisco routers to communicate with those Combinet bridges, the Cisco IOS supports a the CPP encapsulation type.

To enable routers to communicate over ISDN interfaces with Combinet bridges that support only CPP, use the following commands in interface configuration mode:

Command

Purpose

Step 1

Router(config-if)# encapsulation cpp

Specifies CPP encapsulation.

Step 2

Router(config-if)# cpp callback accept

Enables CPP callback acceptance.

Step 3

Router(config-if)# cpp authentication

Enables CPP authentication.

Most Combinet devices support PPP. Cisco routers can communicate over ISDN with these devices by using PPP encapsulation, which supports both routing and fast switching.

Cisco 700 and 800 series routers and bridges (formerly Combinet devices) support only IP, Internet Protocol Exchange (IPX), and bridging. For AppleTalk, Cisco routers automatically perform half-bridging with Combinet devices. For more information about half-bridging, see the section “Configuring PPP Half-Bridging” in the chapter “Configuring Media-Independent PPP and Multilink PPP” later in this publication.

Cisco routers can also half-bridge IP and IPX with Combinet devices that support only CPP. To configure this feature, you only need to set up the addressing with the ISDN interface as part of the remote subnet; no additional commands are required.

Troubleshooting ISDN Special Signaling

Command

Purpose

Router# debug dialer

Displays the values of timers.

Router# debug isdn q921 [interface bri number]

or

Router# debug isdn q921 interface serial slot/controller-number:23

Router# debug isdn q931 [interface bri number]

Router# debug isdn q931 interface serial slot/controller-number:23

Configuration Examples for ISDN Special Signaling

This section provides the following configuration examples:

- ISDN AOC Configuration Examples

- ISDN NFAS Configuration Examples

ISDN AOC Configuration Examples

This section provides the following ISDN AOC configuration examples:

- Using Legacy DDR for ISDN PRI AOC Configuration

- Using Dialer Profiles for ISDN BRI AOC Configuration

Using Legacy DDR for ISDN PRI AOC Configuration

This example shows ISDN PRI configured on an E1 controller. Legacy DDR is configured on the ISDN D channel (serial interface 0:15) and propagates to all ISDN B channels. A static dialer idle-timeout is configured for all incoming calls on the B channels, but the map classes are configured independently of it. Map classes Kappa and Beta use AOC charging unit duration to calculate the timeout for the call. A short-hold idle timer is set so that if the line is idle for 10 or more seconds, the call is disconnected when the current charging period ends. Map class Iota uses a static idle timeout.

version 11.2

service timestamps debug datetime msec

service timestamps log datetime msec

!

hostname A

!

username c2503isdn password 7 1511021F0725

username B password 7 110A1016141D29

username C password 7 1511021F072508

isdn switch-type primary-net5

!

controller E1 0

pri-group timeslots 1-31

!

interface Serial 0:15

ip address 10.0.0.35 255.0.0.0

encapsulation ppp

dialer idle-timeout 150

dialer map ip 10.0.0.33 name c2503isdn class Iota 06966600050

dialer map ip 10.0.0.40 name B class Beta 778578

dialer map ip 10.0.0.45 name C class Kappa 778579

dialer-group 1

ppp authentication chap

!

map-class dialer Kappa

dialer idle-timeout 300

dialer isdn short-hold 120

!

map-class dialer Iota

dialer idle-timeout 300

!

map-class dialer Beta

dialer idle-timeout 300

dialer isdn short-hold 90

!

dialer-list 1 protocol ip permit

Using Dialer Profiles for ISDN BRI AOC Configuration

This example shows ISDN BRI configured as a member of two dialer pools for dialer profiles.

version 11.2

service timestamps debug datetime msec

service timestamps log datetime msec

!

hostname delorean

!

username spanky password 7 0705344245

username delorean password 7 1511021F0725

isdn switch-type basic-net3

!

interface BRI0

description Connected to NTT 81012345678901

no ip address

dialer pool-member 1 max-link 1

dialer pool-member 2 max-link

encapsulation ppp

no fair-queue

!

interface Dialer1

ip address 10.1.1.8 255.255.255.0

encapsulation ppp

dialer remote-name spanky

dialer string 81012345678902 class Omega

dialer pool 1

dialer-group 1

ppp authentication chap

!

interface Dialer2

ip address 10.1.1.8 255.255.255.0

encapsulation ppp

dialer remote-name dmsisdn

dialer string 81012345678902 class Omega

dialer string 14153909503 class Gamma

dialer pool 2

dialer-group 1

ppp authentication chap

!

map-class dialer Omega

dialer idle-timeout 60

dialer isdn short-hold 150

!

map-class dialer Gamma

dialer isdn short-hold 60

!

dialer-list 1 protocol ip permit

ISDN NFAS Configuration Examples

This section provides the following configuration examples:

- NFAS Primary and Backup D Channels

- PRI Interface Service State

- NTT PRI NFAS Primary D Channel Example

NFAS Primary and Backup D Channels

The following example configures ISDN PRI and NFAS on three T1 controllers of a Cisco 7500 series router. The NFAS primary D channel is configured on the 1/0 controller, and the NFAS backup D channel is configured on the 1/1 controller. No NFAS D channel is configured on the 2/0 controller; it is configured for 24 B channels. Once the NFAS primary D channel is configured, it is the only interface you see and need to configure; DDR configuration for the primary D channel—which is distributed to all B channels—is also included in this example.

isdn switch-type primary-4ess

!

! NFAS primary D channel on the channelized T1 controller in 1/0.

controller t1 1/0

framing esf

linecode b8zs

pri-group timeslots 1-24 nfas_d primary nfas_interface 0 nfas_group 1

!

! NFAS backup D channel on the channelized T1 controller in 1/1.

controller t1 1/1

framing esf

linecode b8zs

pri-group timeslots 1-24 nfas_d backup nfas_interface 1 nfas_group 1

!

! NFAS 24 B channels on the channelized T1 controller in 2/0.

controller t1 2/0

framing esf

linecode b8zs

pri-group timeslots 1-24 nfas_d none nfas_interface 2 nfas_group 1

!

! NFAS primary D channel interface configuration for PPP and DDR. This

! configuration is distributed to all the B channels in NFAS group 1 on the

! three channelized T1 controllers.

!

interface Serial 1/0:23

ip address 10.1.1.2 255.255.255.0

no ip mroute-cache

encapsulation ppp

dialer map ip 10.1.1.1 name flyboy 567898

dialer map ip 10.1.1.3 name flyboy 101112345678

dialer map ip 10.1.1.4 name flyboy 01112345678

dialer-group 1

no fair-queue

no cdp enable

ppp authentication chap

PRI Interface Service State

The following example puts the entire PRI interface back in service after it previously had been taken out of service:

isdn service dsl 0 b-channel 0 state 0

NTT PRI NFAS Primary D Channel Example

The following example configures ISDN PRI and NFAS on three T1 controllers of a Cisco 7500 series router. The NFAS primary D channel is configured on the 1/0 controller. No NFAS D channel is configured on the 1/1 and 2/0 controllers; they are configured for 24 B channels. Once the NFAS primary D channel is configured, it is the only interface you see and need to configure. DDR configuration for the primary D channel—which is distributed to all B channels—is also included in this example.

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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2007-2009 Cisco Systems, Inc. All rights reserved.

Configuring Snapshot Routing

This chapter describes how to configure snapshot routing. It includes the following main sections:

- Snapshot Routing Overview

- How to Configure Snapshot Routing

- Monitoring and Maintaining DDR Connections and Snapshot Routing

- Configuration Examples for Snapshot Routing

To identify the hardware platform or software image information associated with a feature, use the Feature Navigator on Cisco.com to search for information about the feature or refer to the software release notes for a specific release. For more information, see the “Identifying Supported Platforms” section in the “Using Cisco IOS Software” chapter.

For a complete description of the snapshot routing commands mentioned in this chapter, refer to the Cisco IOS Dial Technologies Command Reference. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

Snapshot Routing Overview

Snapshot routing enables a single router interface to call other routers during periods when the line protocol for the interface is up (these are called “active periods”). The router dials in to all configured locations during such active periods to get routes from all the remote locations.

The router can be configured to exchange routing updates each time the line protocol goes from “down” to “up” or from “dialer spoofing” to “fully up.” The router can also be configured to dial the server router in the absence of regular traffic if the active period time expires.

Snapshot routing is useful in two command situations:

- Configuring static routes for dial-on-demand routing (DDR) interfaces

- Reducing the overhead of periodic updates sent by routing protocols to remote branch offices over a dedicated serial line

When configuring snapshot routing, you choose one router on the interface to be the client router and one or more other routers to be server routers. The client router determines the frequency at which routing information is exchanged between routers.

Routing information is exchanged during an active period. During the active period, a client router dials all the remote server routers for which it has a snapshot dialer map defined in order to get routes from all the remote locations. The server router provides information about routes to each client router that calls.

At the end of the active period, the router takes a snapshot of the entries in the routing table. These entries remain frozen during a quiet period. At the end of the quiet period, another active period starts during which routing information is again exchanged; see Figure 1.

Figure 1 Active and Quiet Periods in Snapshot Routing

When the router makes the transition from the quiet period to the active period, the line might not be available for a variety of reasons. For example, the line might be down or busy, or the permanent virtual circuit (PVC) might be down. If this happens, the router has to wait through another entire quiet period before it can update its routing table entries. This wait might be a problem if the quiet period is very long—for example, 12 hours. To avoid the need to wait through the quiet period, you can configure a retry period. If the line is not available when the quiet period ends, the router waits for the amount of time specified by the retry period and then makes the transition to an active period. See to Figure 2.

Figure 2 Retry Period in Snapshot Routing

The retry period is also useful in a dialup environment in which there are more remote sites than router interface lines that dial in to a PRI and want routing information from that interface. For example, a PRI has 23 DS0s available, but you might have 46 remote sites. In this situation, you would have more dialer map commands than available lines. The router will try the dialer map commands in order and will use the retry time for the lines that it cannot immediately access.

The following routed protocols support snapshot routing. Note that these are all distance-vector protocols.

- AppleTalk—Routing Table Maintenance Protocol (RTMP)

- Banyan VINES—Routing Table Protocol (RTP)

- IP—Routing Information Protocol (RIP), Interior Gateway Routing Protocol (IGRP)

- Internet Protocol Exchange (IPX)—RIP, Service Advertisement Protocol (SAP)

How to Configure Snapshot Routing

To configure snapshot routing, perform the tasks in the following sections:

- Configuring the Client Router (Required)

- Configuring the Server Router (Required)

You can also monitor and maintain interfaces configured for snapshot routing. For tips on maintaining your network with snapshot routing, see the section “Monitoring and Maintaining DDR Connections and Snapshot Routing” later in this chapter.

For an example of configuring snapshot routing, see the section “Configuration Examples for Snapshot Routing” at the end of this chapter.

Configuring the Client Router

To configure snapshot routing on the client router that is connected to a dedicated serial line, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# interface serial number

Specifies a serial interface.

Step 2

Router(config-if)# snapshot client active-time quiet-time [suppress-statechange-updates] [dialer]

Configures the client router.

To configure snapshot routing on the client router that is connected to an interface configured for DDR, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# interface serial number

Specifies a serial interface.

Step 2

Router(config-if)# dialer rotary-group number

Configures a dialer rotary group.

Step 3

Router(config-if)# interface dialer number

Specifies a dialer interface.

Step 4

Router(config-if)# snapshot client active-time quiet-time [suppress-statechange-updates] [dialer]

Configures the client router.

Step 5

Router(config-if)# dialer map snapshot sequence-number dial-string

Defines a dialer map.

Repeat these steps for each map you want to define. Maps must be provided for all the remote server routers that this client router is to call during each active period.

Because ISDN BRI and PRI automatically have rotary groups, you need not define a rotary group when configuring snapshot routing.

To configure snapshot routing on the client router over an interface configured for BRI or PRI, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# interface bri number

Specifies a BRI interface.

Step 2

Router(config-if)# snapshot client active-time quiet-time [suppress-statechange-updates] [dialer]

Configures the client router.

Step 3

Router(config-if)# dialer map snapshot sequence-number dial-string

Defines a dialer map.

Configuring the Server Router

To configure snapshot routing on the server router that is connected to a dedicated serial line, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# interface serial number

Specifies a serial interface.

Step 2

Router(config-if)# snapshot server active-time [dialer]

Configures the server router.

To configure snapshot routing on the associated server router that is connected to an interface configured for DDR, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# interface serial number

Specifies a serial interface.

Step 2

Router(config-if)# interface dialer number

Specifies a dialer interface.

Step 3

Router(config-if)# snapshot server active-time [dialer]

Configures the server router.

The active period for the client router and its associated server routers should be the same.

Monitoring and Maintaining DDR Connections and Snapshot Routing

Command

Purpose

Router# show dialer [interface type number]

Displays general diagnostics about the DDR interface.

Router# show interfaces bri 0

Displays information about the ISDN interface.

Router# clear snapshot quiet-time interface

Terminates the snapshot routing quiet period on the client router within 2 minutes.

Router# show snapshot [type number]

Displays information about snapshot routing parameters.

Router# clear dialer

Clears the values of the general diagnostic statistics.

Configuration Examples for Snapshot Routing

The following example configures snapshot routing on an interface configured for DDR on the client router. In this configuration, a single client router can call multiple server routers. The client router dials to all different locations during each active period to get routes from all those remote locations.

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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

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Reliable Static Routing Backup Using Object Tracking

First Published: May 10, 2001

Last Updated: November 20, 2009

The Reliable Static Routing Backup Using Object Tracking feature introduces the ability for the Cisco IOS software to use Internet Control Message Protocol (ICMP) pings to identify when a

PPP over Ethernet (PPPoE) or IP Security Protocol (IPsec) Virtual Private Network (VPN) tunnel goes down, allowing the initiation of a backup connection from any alternative port. The Reliable Static Routing Backup Using Object Tracking feature is compatible with both preconfigured static routes and Dynamic Host Configuration Protocol (DHCP) configurations.

Finding Feature Information

For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the “Feature Information for Reliable Static Routing Backup Using Object Tracking” section.

Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Contents

- Prerequisites for Reliable Static Routing Backup Using Object Tracking

- Restrictions for Reliable Static Routing Backup Using Object Tracking

- Information About Reliable Static Routing Backup Using Object Tracking

- How to Configure Reliable Static Routing Backup Using Object Tracking

- Configuration Examples for Reliable Static Routing Backup Using Object Tracking

- Additional References

- Feature Information for Reliable Static Routing Backup Using Object Tracking

Prerequisites for Reliable Static Routing Backup Using Object Tracking

Dial-on-demand routing (DDR) must be configured if the backup connection is configured on a dialer interface. For more information on configuring DDR, refer to the “Dial-on-Demand Routing Configuration” part of the Cisco IOS Dial Technologies Configuration Guide.

Restrictions for Reliable Static Routing Backup Using Object Tracking

This feature is supported in all Cisco IOS software images for the Cisco 1700 series modular access routers except the Cisco IOS IP Base image.

Information About Reliable Static Routing Backup Using Object Tracking

To configure the Reliable Static Routing Backup Using Object Tracking feature, you should understand the following concepts:

- Reliable Static Routing Backup Using Object Tracking

- Cisco IOS IP SLAs

- Benefits of Reliable Static Routing Backup Using Object Tracking

Reliable Static Routing Backup Using Object Tracking

The Reliable Static Routing Backup Using Object Tracking feature introduces the ability to reliably back up PPPoE or IPsec VPN deployments by initiating a DDR connection from an alternative port if the circuit to the primary gateway is interrupted. The Reliable Static Routing Backup Using Object Tracking feature can ensure reliable backup in the case of several catastrophic events, such as Internet circuit failure or peer device failure. A typical scenario is shown in Figure 1.

Figure 1 Reliable Static Routing Backup Using Object Tracking Scenario

Traffic from the remote LAN is forwarded to the main office from the primary interface of the remote router. If the connection to the main office is lost, the status of the tracked object changes from up to down. When the state of the tracked object changes to down, the routing table entry for the primary interface is removed and the preconfigured floating static route is installed on the secondary interface. Traffic is then forwarded to the preconfigured destination from the secondary interface. If DDR is configured on the secondary interface, interesting traffic will trigger DDR. The backup circuit can be configured to use the public switched telephone network (PSTN) or the Internet. When the state of the tracked object changes from down to up, the routing table entry for the primary interface is reinstalled and the floating static route for the secondary interface is removed.

Cisco IOS IP SLAs

The Reliable Static Routing Backup Using Object Tracking feature uses Cisco IOS IP Service Level Agreements (IP SLAs), a network monitoring feature set, to generate ICMP pings to monitor the state of the connection to the primary gateway. Cisco IOS IP SLAs is configured to ping a target, such as a publicly routable IP address or a target inside the corporate network. The pings are routed from the primary interface only. A track object is created to monitor the status of the Cisco IOS IP SLAs configuration. The track object informs the client, the static route, if a state change occurs. The preconfigured floating static route on the secondary interface will be installed when the state changes from up to down.

HTTP GET, User Datagram Protocol (UDP) echo, or any other protocol supported by Cisco IOS IP SLAs can be used instead of ICMP pings.

Benefits of Reliable Static Routing Backup Using Object Tracking

PPPoE and IPsec VPN deployments provide cost-effective and secure Internet-based solutions that can replace traditional dialup and Frame Relay circuits.

The Reliable Static Routing Backup Using Object Tracking feature can determine the state of the primary connection without enabling a dynamic routing protocol.

The Reliable Static Routing Backup Using Object Tracking feature introduces a reliable backup solution for PPPoE and IPsec VPN deployments, allowing these solutions to be used for critical circuits that must not go down without a backup circuit automatically engaging.

How to Configure Reliable Static Routing Backup Using Object Tracking

This section contains the following tasks:

- Configuring the Primary Interface for Reliable Static Routing Backup Using Object Tracking (required)

- Configuring the Backup Interface for Reliable Static Routing Backup Using Object Tracking

- Configuring Network Monitoring with Cisco IOS IP SLAs for Reliable Static Routing Backup Using Object Tracking (required)

- Configuring the Routing Policy for Reliable Static Routing Backup Using Object Tracking (required)

- Configuring the Default Route for the Primary Interface Using Static Routing (required)

- Configuring a Floating Static Default Route on the Secondary Interface (required)

- Verifying the State of the Tracked Object for Reliable Static Routing Backup Using Object Tracking (optional)

Configuring the Primary Interface for Reliable Static Routing Backup Using Object Tracking

You must configure the connection between the primary interface and the remote gateway. The status of this connection will be monitored by the Reliable Static Routing Backup Using Object Tracking feature.

The primary interface can be configured in one of three ways: for PPPoE, DHCP, or static routing. You must choose one of these configuration types. If you are not sure of which method to use with your network configuration, consult your Internet service provider (ISP) or network administrator.

Perform one of the following tasks to configure the primary interface:

- Configuring the Primary Interface for PPPoE

- Configuring the Primary Interface for DHCP

- Configuring the Primary Interface for Static Routing

Configuring the Primary Interface for PPPoE

Perform this task to configure the primary interface for PPPoE.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type number [name-tag]

4. description string

5. no ip address

6. pvc [name] vpi/vci [ces | ilmi | qsaal | smds | l2transport]

7. pppoe-client dial-pool-number number [dial-on-demand]

8. exit

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface type number [name-tag]

Router(config)# interface ATM 2/0

Configures an interface type and enters interface configuration mode.

Step 4

description string

Router(config-if)# description primary-link

Adds a description to the interface configuration.

Step 5

no ip address

Router(config-if)# no ip address

Removes IP addresses configured on the interface.

Step 6

pvc [ name ] vpi / vci [ ces | ilmi | qsaal | smds | l2transport ]

Router(config-if)# pvc 0/33

Creates or assigns a name to an ATM permanent virtual circuit (PVC), specifies the encapsulation type on an ATM PVC, and enters ATM virtual circuit configuration mode.

Step 7

pppoe-client dial-pool-number number [ dial-on-demand ]

Router(config-if-atm-vc)# pppoe-client dial-pool-number 1

Configures a PPPoE client and specifies DDR functionality.

Step 8

exit

Router(config-if-atm-vc)# exit

Exits ATM virtual circuit configuration mode.

Configuring the Primary Interface for DHCP

Perform this task to configure the primary interface for DHCP.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type number [name-tag]

4. description string

5. ip dhcp client route track number

6. ip address dhcp

7. exit

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface type number [name-tag]

Router(config)# interface ethernet 0/0

Configures an interface type and enters interface configuration mode.

Step 4

description string

Router(config-if)# description primary-link

Adds a description to the interface configuration.

Step 5

ip dhcp client route track number

Router(config-if)# ip dhcp client route track 123

Configures the DHCP client to associate any added routes with the specified track number.

- route track number —Associates a track object with the DHCP-installed static route. Valid values for the number argument range from 1 to 500.

command is issued after an IP address has been acquired from DHCP, it will not take effect until the next time the router acquires an IP address from DHCP.

Step 6

ip address dhcp

Router(config-if)# ip address dhcp

Acquires an IP address on an Ethernet interface from DHCP.

Step 7

exit

Router(config-if)# exit

Exits interface configuration mode.

Configuring the Primary Interface for Static Routing

Perform this task to configure the primary interface for static routing.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type number [name-tag]

4. description string

5. ip address ip-address mask [secondary]

6. exit

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface type number [name-tag]

Router(config)# interface FastEthernet 0/0

Configures an interface type and enters interface configuration mode.

Step 4

description string

Router(config-if)# description primary-link

Adds a description to the interface configuration.

Step 5

ip address ip-address mask [secondary]

Router(config-if)# ip address 209.165.200.225 255.0.0.0

Sets a primary or secondary IP address for an interface.

Step 6

exit

Router(config-if)# exit

Exits interface configuration mode.

Configuring the Backup Interface for Reliable Static Routing Backup Using Object Tracking

You must configure a backup interface to contact the remote gateway. If the connection between the primary interface and the remote gateway goes down, the backup interface will be used.

Perform the following task to configure the backup interface. This task applies to PPPoE, DHCP, and static routing configurations.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type number [name-tag]

4. description string

5. ip address ip-address mask [secondary]

6. exit

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

interface type number [name-tag]

Router(config)# interface Dialer 0

Configures an interface type and enters interface configuration mode.

Step 4

description string

Router(config-if)# description backup-link

Adds a description to an interface configuration.

Step 5

ip address ip-address mask [secondary]

Router(config-if)# ip address 209.165.201.1 255.255.255.0

Sets a secondary IP address for an interface.

Note If the connection on the primary interface goes down, the secondary interface is used as a backup interface.

Step 6

exit

Router(config-if)# exit

Exits interface configuration mode.

Configuring Network Monitoring with Cisco IOS IP SLAs for Reliable Static Routing Backup Using Object Tracking

The Reliable Static Routing Backup Using Object Tracking feature uses a Cisco IOS IP SLAs configuration to generate ICMP pings to monitor the state of the connection to the primary gateway.

Beginning in Cisco IOS Release 12.3(14)T, the command used to configure Cisco IOS IP SLAs was modified.

Perform one of the following tasks to configure Cisco IOS IP SLAs depending on which Cisco IOS software release you are running:

- Configuring Cisco IOS IP SLAs for Cisco IOS Release 12.3(8)T, 12.3(11)T, 12.2(33)SRA, and 12.2(33)SRE

- Configuring Cisco IOS IP SLAs for Cisco IOS Release 12.3(14)T, 12.4, 12.4(2)T, and 12.2(33)SXH

- Configuring Cisco IOS IP SLAs for Cisco IOS Release 12.4(4)T, 15.(0)1M, and Later Releases

Configuring Cisco IOS IP SLAs for Cisco IOS Release 12.3(8)T, 12.3(11)T, 12.2(33)SRA, and 12.2(33)SRE

Perform this task to create Cisco IOS IP SLAs depending on which Cisco IOS software release you are running. This task applies to PPPoE, DHCP, and static routing configurations.

SUMMARY STEPS

1. enable

2. configure terminal

3. rtr [operation-number]

4. type echo protocol ipIcmpEcho {destination-ip-address | destination-hostname} [source-ipaddr {ip-address | hostname}]

5. timeout milliseconds

6. frequency seconds

7. threshold milliseconds

8. exit

9. rtr schedule operation-number [life {forever | seconds}] [start-time {hh:mm[:ss] [month day | day month] | pending | now | after hh:mm:ss}] [ageout seconds]

10. track object-number rtr rtr-operation {state | reachability}

11. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

rtr [operation-number]

Router(config)# rtr 1

Begins configuration for a Cisco IOS IP SLAs operation and enters RTR configuration mode.

Step 4

type echo protocol ipIcmpEcho { destination-ip-address | destination-hostname } [ source-ipaddr { ip-address | hostname }]

Router(config-rtr)# type echo protocol ipIcmpEcho 172.16.23.7

Configures a Cisco IOS IP SLAs end-to-end echo response time probe operation.

Step 5

timeout milliseconds

Router(config-rtr)# timeout 1000

Sets the amount of time for which the Cisco IOS IP SLAs operation waits for a response from its request packet.

Step 6

frequency seconds

Router(config-rtr)# frequency 3

Sets the rate at which a specified Cisco IOS IP SLAs operation is sent into the network.

Step 7

threshold milliseconds

Router(config-rtr)# threshold 2

Sets the rising threshold (hysteresis) that generates a reaction event and stores history information for the Cisco IOS IP SLAs operation.

Step 8

exit

Router(config-rtr)# exit

Exits RTR configuration mode.

Step 9

rtr schedule operation-number [life {forever | seconds}] [start-time {hh:mm[:ss] [month day | day month] | pending | now | after hh:mm:ss}] [ageout seconds]

Router(config)# rtr schedule 1 life forever start-time now

Configures a Cisco IOS IP SLAs ICMP echo operation.

Step 10

track object-number rtr rtr-operation {state | reachability}

Router(config)# track 123 rtr 1 reachability

Tracks the state of a Cisco IOS IP SLAs operation and enters tracking configuration mode.

Step 11

end

Router(config-track-list)# end

Exits tracking configuration mode.

Configuring Cisco IOS IP SLAs for Cisco IOS Release 12.3(14)T, 12.4, 12.4(2)T, and 12.2(33)SXH

Perform this task to create an Cisco IP SLAs configuration to ping the target address depending on which Cisco IOS software release you are running. This task applies to PPPoE, DHCP, and static routing configurations.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip sla monitor [operation-number]

4. type echo protocol ipIcmpEcho {destination-ip-address | destination-hostname} [source-ipaddr {ip-address | hostname} | source-interface interface-name]

5. timeout milliseconds

6. frequency seconds

7. threshold milliseconds

8. exit

9. ip sla monitor schedule operation-number [life {forever | seconds}] [start-time {hh:mm[:ss] [month day | day month] | pending | now | after hh:mm:ss}] [ageout seconds] [recurring]

10. track object-number rtr rtr-operation {state | reachability}

11. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

ip sla monitor [operation-number]

Router(config)# ip sla monitor 1

Begins configuring a Cisco IOS IP SLAs operation and enters IP SLA monitor configuration mode.

Step 4

type echo protocol ipIcmpEcho { destination-ip-address | destination-hostname } [ source-ipaddr { ip-address | hostname } | source-interface interface-name ]

Router(config-sla-monitor)# type echo protocol ipIcmpEcho 172.16.23.7

Configures a Cisco IOS IP SLAs end-to-end ICMP echo response time operation and enters IP SLAs ICMP echo configuration mode.

Step 5

timeout milliseconds

Router(config-sla-monitor-echo)# timeout 1000

Sets the amount of time for which the Cisco IOS IP SLAs operation waits for a response from its request packet.

Step 6

frequency seconds

Router(config-sla-monitor-echo)# frequency 3

Sets the rate at which a specified Cisco IOS IP SLAs operation is sent into the network.

Step 7

threshold milliseconds

Router(config-sla-monitor-echo)# threshold 2

Sets the rising threshold (hysteresis) that generates a reaction event and stores history information for the Cisco IOS IP SLAs operation.

Step 8

exit

Router(config-sla-monitor-echo)# exit

Exits IP SLAs ICMP echo configuration mode.

Step 9

ip sla monitor schedule operation-number [life {forever | seconds}] [start-time {hh:mm[:ss] [month day | day month] | pending | now | after hh:mm:ss}] [ageout seconds] [recurring]

Router(config)# ip sla monitor schedule 1 life forever start-time now

Configures the scheduling parameters for a single Cisco IOS IP SLAs operation.

Step 10

track object-number rtr rtr-operation {state | reachability}

Router(config)# track 123 rtr 1 reachability

Tracks the state of a Cisco IOS IP SLAs operation and enters tracking configuration mode.

Step 11

end

Router(config-track-list)# end

Exits tracking configuration mode.

Configuring Cisco IOS IP SLAs for Cisco IOS Release 12.4(4)T, 15.(0)1M, and Later Releases

Perform this task to create Cisco IP SLAs configuration in Cisco IOS Release 12.4(4)T, 15.0(1)M, and later releases to ping the target address. This task applies to PPPoE, DHCP, and static routing configurations.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip sla [operation-number]

4. icmp-echo {destination-ip-address | destination-hostname} [source-ip {ip-address | hostname} | source-interface interface-name]

5. timeout milliseconds

6. frequency seconds

7. threshold milliseconds

8. exit

9. ip sla schedule operation-number [life {forever | seconds}] [start-time {hh:mm[:ss] [month day | day month] | pending | now | after hh:mm:ss}] [ageout seconds] [recurring]

10. track object-number rtr rtr-operation {state | reachability}

11. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

ip sla [operation-number]

Router(config)# ip sla 1

Begins configuring a Cisco IOS IP SLAs operation and enters IP SLA configuration mode.

Step 4

icmp-echo { destination-ip-address | destination-hostname } [ source-ip { ip-address | hostname } | source-interface interface-name ]

Router(config-ip-sla)# icmp-echo 172.16.23.7

Configures a Cisco IOS IP SLAs end-to-end ICMP echo response time operation and enters IP SLAs ICMP echo configuration mode.

Step 5

timeout milliseconds

Router(config-ip-sla-echo)# timeout 1000

Sets the amount of time for which the Cisco IOS IP SLAs operation waits for a response from its request packet.

Step 6

frequency seconds

Router(config-ip-sla-echo)# frequency 3

Sets the rate at which a specified Cisco IOS IP SLAs operation is sent into the network.

Step 7

threshold milliseconds

Router(config-ip-sla-echo)# threshold 2

Sets the rising threshold (hysteresis) that generates a reaction event and stores history information for the Cisco IOS IP SLAs operation.

Step 8

exit

Router(config-ip-sla-echo)# exit

Exits IP SLAs ICMP echo configuration mode.

Step 9

ip sla schedule operation-number [life {forever | seconds}] [start-time {hh:mm[:ss] [month day | day month] | pending | now | after hh:mm:ss}] [ageout seconds] [recurring]

Router(config-ip-sla-echo)# ip sla schedule 1 life forever start-time now

Configures the scheduling parameters for a single Cisco IOS IP SLAs operation.

Step 10

track object-number rtr rtr-operation {state | reachability}

Router(config)# track 123 rtr 1 reachability

Tracks the state of a Cisco IOS IP SLAs operation and enters tracking configuration mode.

Step 11

end

Router(config-track-list)# end

Exits tracking configuration mode.

Configuring the Routing Policy for Reliable Static Routing Backup Using Object Tracking

In order to track the status of the primary connection to the remote gateway, the Cisco IOS IP SLAs ICMP pings must be routed only from the primary interface.

Perform one of the following tasks to configure a routing policy that will ensure that the Cisco IOS IP SLAs pings are always routed out of the primary interface:

- Configuring a Routing Policy for PPPoE

- Configuring a Routing Policy for DHCP

- Configuring a Routing Policy for Static Routing

Configuring a Routing Policy for PPPoE

Perform this task to configure a routing policy if the primary interface is configured for PPPoE.

SUMMARY STEPS

1. enable

2. configure terminal

3. access-list access-list-number [dynamic dynamic-name [timeout minutes]] {deny | permit} icmp source source-wildcard destination destination-wildcard [icmp-type [icmp-code] | icmp-message] [precedence precedence] [tos tos] [log | log-input] [time-range time-range-name] [fragments]

4. route-map map-tag [permit | deny] [sequence-number]

5. match ip address {access-list-number | access-list-name} [... access-list-number | ... access-list-name]

6. set interface type number [... type number]

7. exit

8. ip local policy route-map map-tag

9. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

access-list access-list-number [dynamic dynamic-name [timeout minutes]] {deny | permit} icmp source source-wildcard destination destination-wildcard [icmp-type [icmp-code] | icmp-message] [precedence precedence] [tos tos] [log | log-input] [time-range time-range-name] [fragments]

Router(config)# access-list 101 permit icmp any host 172.16.23.7 echo

Defines an extended IP access list.

Step 4

route-map map-tag [permit | deny] [sequence-number]

Router(config)# route-map MY-LOCAL-POLICY permit 10

Enters route-map configuration mode and defines the conditions for redistributing routes from one routing protocol into another.

Step 5

match ip address {access-list-number | access-list-name} [... access-list-number | ... access-list-name]

Router(config-route-map)# match ip address 101

Distributes any routes that have a destination network number address that is permitted by a standard or extended access list, or performs policy routing on packets.

Step 6

set interface type number [... type number]

Router(config-route-map)# set interface null 0

Indicates where to output packets that pass a match clause of a route map for policy routing.
in this scenario. If the next hop is not set because the interface is down, the packet is routed to the null interface and discarded. Otherwise policy routing fails and the packet is routed using the Routing Information Base (RIB) card. Routing the packet using the RIB card is undesirable.

Step 7

exit

Router(config-route-map)# exit

Exits route-map configuration mode.

Step 8

ip local policy route-map map-tag

Router(config)# ip local policy route-map MY-LOCAL-POLICY

Identifies a route map to use for local policy routing.

Step 9

end

Router(config)# end

Exits global configuration mode.

Configuring a Routing Policy for DHCP

Perform this task to ensure that the primary interface is configured for DHCP:

SUMMARY STEPS

1. enable

2. configure terminal

3. access-list access-list-number [dynamic dynamic-name [timeout minutes]] {deny | permit} icmp source source-wildcard destination destination-wildcard [icmp-type [icmp-code] | icmp-message] [precedence precedence] [tos tos] [log | log-input] [time-range time-range-name] [fragments]

4. route-map map-tag [permit | deny] [sequence-number]

5. match ip address {access-list-number | access-list-name} [... access-list-number | ... access-list-name]

6. set ip next-hop dynamic dhcp

7. exit

8. ip local policy route-map map-tag

9. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

access-list access-list-number [dynamic dynamic-name [timeout minutes]] {deny | permit} icmp source source-wildcard destination destination-wildcard [icmp-type [icmp-code] | icmp-message] [precedence precedence] [tos tos] [log | log-input] [time-range time-range-name] [fragments]

Router(config)# access-list 101 permit icmp any host 172.16.23.7 echo

Defines an extended IP access list.

Step 4

route-map map-tag [permit | deny] [sequence-number]

Router(config)# route-map MY-LOCAL-POLICY permit 10

Enters route-map configuration mode and defines the conditions for redistributing routes from one routing protocol into another.

Step 5

match ip address {access-list-number | access-list-name} [... access-list-number | ... access-list-name]

Router(config-route-map)# match ip address 101

Distributes any routes that have a destination network number address that is permitted by a standard or extended access list, or performs policy routing on packets.

Step 6

set ip next-hop dynamic dhcp

Router(config-route-map)# set ip next-hop dynamic dhcp

Sets the next hop to the gateway that was most recently learned by the DHCP client.

Step 7

exit

Router(config-route-map)# exit

Exits route-map configuration mode.

Step 8

ip local policy route-map map-tag

Router(config)# ip local policy route-map MY-LOCAL-POLICY

Identifies a route map to use for local policy routing.

Step 9

end

Router(config)# end

Exits global configuration mode.

Configuring a Routing Policy for Static Routing

Perform one of the following tasks if the primary interface is configured for static routing:

- Configuring a Routing Policy for Static Routing with a Point-to-Point Primary Gateway

- Configuring a Routing Policy for Static Routing with a Multipoint Primary Gateway

Configuring a Routing Policy for Static Routing with a Point-to-Point Primary Gateway

Perform this task to configure a routing policy if the primary interface is configured for static routing and the primary gateway is a point-to-point gateway.

SUMMARY STEPS

1. enable

2. configure terminal

3. access-list access-list-number [dynamic dynamic-name [timeout minutes]] {deny | permit} icmp source source-wildcard destination destination-wildcard [icmp-type [icmp-code] | icmp-message] [precedence precedence] [tos tos] [log | log-input] [time-range time-range-name] [fragments]

4. route-map map-tag [permit | deny] [sequence-number]

5. match ip address {access-list-number | access-list-name} [... access-list-number | ... access-list-name]

6. set interface type number [... type number]

7. exit

8. ip local policy route-map map-tag

9. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

access-list access-list-number [dynamic dynamic-name [timeout minutes]] {deny | permit} icmp source source-wildcard destination destination-wildcard [icmp-type [icmp-code] | icmp-message] [precedence precedence] [tos tos] [log | log-input] [time-range time-range-name] [fragments]

Router(config)# access-list 101 permit icmp any host 172.16.23.7 echo

Defines an extended IP access list.

Step 4

route-map map-tag [permit | deny] [sequence-number]

Router(config)# route-map MY-LOCAL-POLICY permit 10

Enters route-map configuration mode and defines the conditions for redistributing routes from one routing protocol into another.

Step 5

match ip address {access-list-number | access-list-name} [... access-list-number | ... access-list-name]

Router(config-route-map)# match ip address 101

Distributes any routes that have a destination network number address that is permitted by a standard or extended access list, or performs policy routing on packets.

Step 6

set interface type number [...type number]

Router(config-route-map)# set interface dialer 0 Null 0

Indicates where to output packets that pass a match clause of a route map for policy routing.

Step 7

exit

Router(config-route-map)# exit

Exits route-map configuration mode.

Step 8

ip local policy route-map map-tag

Router(config)# ip local policy route-map MY-LOCAL-POLICY

Identifies a route map to use for local policy routing.

Step 9

end

Router(config)# end

Exits global configuration mode.

Configuring a Routing Policy for Static Routing with a Multipoint Primary Gateway

Perform this task to configure a routing policy if the primary interface is configured for static routing and the primary gateway is a multipoint gateway.

SUMMARY STEPS

1. enable

2. configure terminal

3. access-list access-list-number [dynamic dynamic-name [timeout minutes]] {deny | permit} icmp source source-wildcard destination destination-wildcard [icmp-type [icmp-code] | icmp-message] [precedence precedence] [tos tos] [log | log-input] [time-range time-range-name] [fragments]

4. route-map map-tag [permit | deny] [sequence-number]

5. match ip address {access-list-number | access-list-name} [... access-list-number | ... access-list-name]

6. set ip next-hop ip-address [... ip-address]

7. set interface type number [... type number]

8. exit

9. ip local policy route-map map-tag

10. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

access-list access-list-number [dynamic dynamic-name [timeout minutes]] {deny | permit} icmp source source-wildcard destination destination-wildcard [icmp-type [icmp-code] | icmp-message] [precedence precedence] [tos tos] [log | log-input] [time-range time-range-name] [fragments]

Router(config)# access-list 101 permit icmp any host 172.16.23.7 echo

Defines an extended IP access list.

Step 4

route-map map-tag [permit | deny] [sequence-number]

Router(config)# route-map MY-LOCAL-POLICY permit 10

Enters route-map configuration mode and defines the conditions for redistributing routes from one routing protocol into another.

Step 5

match ip address {access-list-number | access-list-name} [... access-list-number | ... access-list-name]

Router(config-route-map)# match ip address 101

Distributes any routes that have a destination network number address that is permitted by a standard or extended access list, or performs policy routing on packets.

Step 6

set ip next-hop ip-address [... ip-address]

Router(config-route-map)# set ip next-hop 10.1.1.242

Indicates where to output packets that pass a match clause of a route map for policy routing.

Step 7

set interface type number [... type number]

Router(config-route-map)# set interface null 0

Indicates where to output packets that pass a match clause of a route map for policy routing.

Step 8

exit

Router(config-route-map)# exit

Exits route-map configuration mode.

Step 9

ip local policy route-map map-tag

Router(config)# ip local policy route-map MY-LOCAL-POLICY

Identifies a route map to use for local policy routing.

Step 10

end

Router(config)# end

Exits global configuration mode.

Configuring the Default Route for the Primary Interface Using Static Routing

Perform this task to configure the static default route only if you are using static routing.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip route prefix mask {ip-address | interface-type interface-number [ip-address]} [distance] [name] [permanent | track number] [tag tag]

4. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

ip route prefix mask {ip-address | interface-type interface-number [ip-address]} [distance] [name] [permanent | track number] [tag tag]

Router(config)# ip route 0.0.0.0 0.0.0.0 10.1.1.242 track 123

Establishes static routes.

- track number —Specifies that the static route will be installed only if the configured track object is up.

Step 4

end

Router(config)# end

Exits global configuration mode.

Configuring a Floating Static Default Route on the Secondary Interface

Perform this task to configure a floating static default route on the secondary interface. This task applies to PPPoE, DHCP, and static routing configurations.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip route network-number network-mask {ip-address | interface} [distance] [name name]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Router# configure terminal

Enters global configuration mode.

Step 3

ip route network-number network-mask {ip-address | interface} [distance] [name name]

Router(config)# ip route 0.0.0.0 0.0.0.0 10.2.2.125 254

Establishes static routes and defines the next hop.

Verifying the State of the Tracked Object for Reliable Static Routing Backup Using Object Tracking

Perform the following task to determine if the state of the tracked object is up or down.

SUMMARY STEPS

1. enable

2. show ip route track-table

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

show ip route track-table

Router# show ip route track-table

Displays information about the IP route track table.

Configuration Examples for Reliable Static Routing Backup Using Object Tracking

This section provides the following configuration examples:

- Configuring Reliable Static Routing Backup Using Object Tracking Using PPPoE: Example

- Configuring Reliable Static Routing Backup Using Object Tracking Using DHCP: Example

- Configuring Reliable Static Routing Backup Using Object Tracking: Example

- Verifying the State of the Tracked Object: Example

Configuring Reliable Static Routing Backup Using Object Tracking Using PPPoE: Example

The following example shows how to configure the Reliable Static Routing Backup Using Object Tracking feature using PPPoE. The primary interface is an ATM interface, and the backup interface is a BRI interface. This example applies to Cisco IOS Release 12.3(8)T, 12.3(11)T, 12.2(33)SRA, 12.2(33)SXH, and 12.2(33)SRE.

interface ATM 0

description primary-link

no ip address

pvc 0/33

pppoe-client dial-pool-number 1

!

interface BRI 0

description backup-link

ip address 10.2.2.2 255.0.0.0

!

rtr 1

type echo protocol ipIcmpEcho 172.16.23.7

timeout 1000

frequency 3

threshold 2

rtr schedule 1 life forever start-time now

track 123 rtr 1 reachability

access list 101 permit icmp any host 172.16.23.7 echo

route map MY-LOCAL-POLICY permit 10

match ip address 101

set interface null 0

!

ip local policy route-map MY-LOCAL-POLICY

ip route 0.0.0.0 0.0.0.0 10.2.2.125 254

Configuring Reliable Static Routing Backup Using Object Tracking Using DHCP: Example

The following example show how to configure the Reliable Static Routing Backup Using Object Tracking feature using DHCP. The primary interface is an Ethernet interface, and the backup interface is a serial interface. This example applies to Cisco IOS Release 12.3(14)T.

!

ip dhcp-client default-router distance 25

ip sla monitor 1

type echo protocol ipIcmpEcho 172.16.23.7

timeout 1000

threshold 2

frequency 3

ip sla monitor schedule 1 life forever start-time now

track 123 rtr 1 reachability

!

interface Ethernet0/0

description primary-link

ip dhcp client route track 123

ip address dhcp

!

interface Serial2/0

description backup-link

ip address 209.165.202.129 255.255.255.255

!

ip local policy route-map MY-LOCAL-POLICY

ip route 0.0.0.0 0.0.0.0 10.2.2.125 254

!

access-list 101 permit icmp any host 172.16.23.7 echo

route-map MY-LOCAL-POLICY permit 10

match ip address 101

set ip next-hop dynamic dhcp

Configuring Reliable Static Routing Backup Using Object Tracking: Example

The following example shows how to configure the Reliable Static Routing Backup Using Object Tracking feature using static routing for a point-to-point primary gateway. The primary interface is a PPPoE Fast Ethernet interface, and the backup interface is a dialer interface. This example applies to Cisco IOS Release 12.3(14)T and later releases.

interface FastEthernet 0/0

description primary-link

ip address 209.165.202.129 255.255.255.255

interface Dialer 0

description backup-link

ip address 209.165.200.225 255.255.255.255

ip sla monitor 1

type echo protocol ipIcmpEcho 172.16.23.7

timeout 1000

frequency 3

threshold 2

ip sla monitor schedule 1 life forever start-time now

track 123 rtr 1 reachability

access list 101 permit icmp any host 172.16.23.7 echo

route map MY-LOCAL-POLICY permit 10

match ip address 101

set interface dialer 0 null 0

!

ip local policy route-map MY-LOCAL-POLICY

ip route 0.0.0.0 0.0.0.0 10.1.1.242 track 123

ip route 0.0.0.0 0.0.0.0 10.2.2.125 254

The following example configures the Reliable Static Routing Backup Using Object Tracking feature using static routing for a multipoint primary gateway. Both the primary interface and the backup interface are Ethernet interfaces. This example applies to Cisco IOS Release 12.3(14)T and later releases.

interface ethernet 0

description primary-link

ip address 209.165.202.129 255.255.255.255

interface ethernet 1

description backup-link

ip address 209.165.200.225 255.255.255.255

ip sla monitor 1

type echo protocol ipIcmpEcho 172.16.23.7

timeout 1000

frequency 3

threshold 2

ip sla monitor schedule 1 life forever start-time now

track 123 rtr 1 reachability

access list 101 permit icmp any host 172.16.23.7 echo

route map MY-LOCAL-POLICY permit 10

match ip address 101

set ip next-hop 10.1.1.242

set interface null 0

!

ip local policy route-map MY-LOCAL-POLICY

ip route 0.0.0.0 0.0.0.0 10.1.1.242 track 123

ip route 0.0.0.0 0.0.0.0 10.2.2.125 254

Verifying the State of the Tracked Object: Example

The following example displays information about track objects in the IP route track table:

Router# show ip route track-table

ip route 0.0.0.0 0.0.0.0 10.1.1.242 track-object 123 state is [up]

Additional References

The following sections provide references related to the Reliable Static Routing Backup Using Object Tracking feature.

Related Documents

Related Topic

Document Title

IPsec configuration tasks

“IP Security VPN Monitoring” module in the Cisco IOS Security Configuration Guide

IPsec commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples

Cisco IOS Security Command Reference

VPDN configuration tasks

“Configuring AAA for VPDN” module in the Cisco IOS VPDN Configuration Guide

VPDN commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples

Cisco IOS VPDN Command Reference

ATM virtual circuit bundles

“ATM RBE” module in the Cisco IOS Broadband Access Aggregation and DSL Configuration Guide

PPPoE commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples

Cisco IOS Wide-Area Networking Command Reference

Dial access specialized features

“Dial Access Specialized Features” module in the Cisco IOS Dial Technologies Configuration Guide

DDR commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples

Cisco IOS Dial Technologies Command Reference

IP SLAs configuration tasks

“IP SLAs” module in the Cisco IOS IP SLAs Configuration Guide

IP SLAs commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples

Cisco IOS IP SLAs Command Reference

Standards

Standards

Title

None

—

MIBs

MIBs

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

RFCs

RFCs

Title

None

—

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/techsupport

Feature Information for Reliable Static Routing Backup Using Object Tracking

Table 1 lists the features in this module and provides links to specific configuration information. Only features that were introduced or modified in Cisco IOS Release 12.2(33)SX or Cisco IOS Releases 12.2(33)SRE or 15.0(1)M or a later release appear in this table.

Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Table 1 Feature Information for Reliable Static Routing Backup Using Object Tracking

Feature Name

Releases

Feature Information

Reliable Static Routing Backup Using Object Tracking

12.2(33)SXH

12.2(33)SRA

12.2(33)SRE

12.3(8)T

12.3(14)T

15.0(1)M

The Reliable Static Routing Backup Using Object Tracking feature introduces the ability for the Cisco IOS software to use ICMP pings to identify when a PPPoE or IPsec VPN tunnel goes down, allowing the initiation of a backup connection from any alternative port. The Reliable Static Routing Backup Using Object Tracking feature is compatible with both preconfigured static routes and DHCP configurations. The following sections provide information about this feature:

- Information About Reliable Static Routing Backup Using Object Tracking

- How to Configure Reliable Static Routing Backup Using Object Tracking

The following commands were introduced or modified: ip dhcp client route, ip route prefix mask, set ip next-hop dynamic, and show ip route track-table.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2001—2009 Cisco Systems, Inc. All rights reserved.

Configuring Dial Backup for Serial Lines

This chapter describes how to configure the primary interface to use the dial backup interface. It includes the following main sections:

- Backup Serial Interface Overview

- How to Configure Dial Backup

- Configuration Examples for Dial Backup for Serial Interfaces

To identify the hardware platform or software image information associated with a feature, use the Feature Navigator on Cisco.com to search for information about the feature or refer to the software release notes for a specific release. For more information, see the “Identifying Supported Platforms” section in the “Using Cisco IOS Software” chapter.

For a complete description of the dial backup commands in this chapter, refer to the Cisco IOS Dial Technologies Command Reference. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

Backup Serial Interface Overview

For a backup serial interface, an external DCE device, such as a modem attached to a circuit-switched service, must be connected to the backup serial interface. The external device must be capable of responding to a data terminal ready (DTR) Active signal by automatically dialing the preconfigured telephone number of the remote site.

A backup interface is an interface that stays idle until certain circumstances occur; then it is activated. A backup interface for a serial interface can be an ISDN interface or a different serial interface. A backup interface can be configured to be activated when any of the following three circumstances occurs:

- The primary line goes down.

- The load on the primary line reaches a certain threshold.

- The load on the primary line exceeds a specified threshold.

To configure a dial backup to a serial interface, you must configure the interface to use the dial backup interface, specify the conditions in which the backup interface will be activated, and then configure the dial-backup interface for dial-on-demand routing (DDR). The DDR configuration specifies the conditions and destinations for dial calls. The serial interface (often called the primary interface) might be configured for DDR or for Frame Relay or X.25 over a leased line, but the backup tasks are the same in all three cases.

Note Dial backup is also available using the Dialer Watch feature. Dialer Watch is based on routing characteristics instead of relying exclusively on interesting traffic conditions. For information about Dialer Watch, see the chapter “Configuring Dial Backup Using Dialer Watch” in this publication.

To configure a backup interface for a serial interface based on one of the conditions listed, complete the following general steps:

- Specify the interface and configure it as needed (for DDR, Frame Relay, or X.25). You can also specify and configure a Frame Relay subinterface.

Refer to the chapters “Configuring Frame Relay” or “Configuring X.25” in the Cisco IOS Wide-Area Networking Configuration Guide. In this publication, see the chapter “Configuring Synchronous Serial Ports” and related chapters in the “Dial-on-Demand Routing” part for details.

- Configure the primary interface or subinterface by specifying the dial backup interface and the conditions for activating the backup interface, as described in this chapter.

- Configure the backup interface for DDR, as described in the “Dial-on-Demand Routing” part of this publication.

See the chapters “Configuring Legacy DDR Spokes” (for point-to-point legacy DDR connections) or “Configuring Legacy DDR Hubs” (for point-to-multipoint legacy DDR connections) in this publication. If you have configured dialer profiles instead of legacy DDR, see the chapter “Configuring Dial Backup with Dialer Profiles” in this publication for backup information.

How to Configure Dial Backup

You must decide whether to activate the backup interface when the primary line goes down, when the traffic load on the primary line exceeds the defined threshold, or both. The tasks you perform depend on your decision. Perform the tasks in the following sections to configure dial backup:

- Specifying the Backup Interface (Optional)

- Defining the Traffic Load Threshold (Optional)

- Defining Backup Line Delays (Optional)

Then configure the backup interface for DDR, so that calls are placed as needed. See the chapters in the “Dial-on-Demand Routing” part of this publication for more information.

For simple configuration examples, see the section “Configuration Examples for Dial Backup for Serial Interfaces” at the end of this chapter.

Specifying the Backup Interface

Command

Purpose

Router(config-if)# backup interface type number

or

Cisco 7500 series routers:

Router(config-if)# backup interface type slot/port

or

Cisco 7200 series routers:

Router(config-if)# backup interface type slot/port-adapter/port

Selects a backup interface.

Note When you enter the backup interface command, the configured physical or logical interface will be forced to standby mode. When you use a BRI for a dial backup (with Legacy DDR), neither of the B channels can be used because the physical BRI interface is in standby mode. However, with dialer profiles, only the logical dialer interface is placed in standby mode and the physical interface (BRI) still can be used for other connections by making it a member of another pool.

When configured for legacy DDR, the backup interface can back up only one interface. For examples of selecting a backup line, see the sections “Dial Backup Using an Asynchronous Interface Example” and “Dial Backup Using DDR and ISDN Example” later in this chapter.

Defining the Traffic Load Threshold

You can configure dial backup to activate the secondary line based on the traffic load on the primary line. The software monitors the traffic load and computes a 5-minute moving average. If this average exceeds the value you set for the line, the secondary line is activated and, depending upon how the line is configured, some or all of the traffic will flow onto the secondary dialup line.

Command

Purpose

Router(config-if)# backup load {enable-threshold | never} {disable-load | never}

Defines the traffic load threshold as a percentage of the available bandwidth of the primary line.

Defining Backup Line Delays

You can configure a value that defines how much time should elapse before a secondary line status changes after a primary line status has changed. You can define two delays:

- A delay that applies after the primary line goes down but before the secondary line is activated

- A delay that applies after the primary line comes up but before the secondary line is deactivated

Command

Purpose

Router(config-if)# backup delay {enable-delay | never} {disable-delay | never}

Defines backup line delays.

For examples of how to define backup line delays, see the sections “Dial Backup Using an Asynchronous Interface Example” and “Dial Backup Using DDR and ISDN Example” at the end of this chapter.

Configuration Examples for Dial Backup for Serial Interfaces

The following sections present examples of specifying the backup interface:

- Dial Backup Using an Asynchronous Interface Example

- Dial Backup Using DDR and ISDN Example

The following sections present examples of backup interfaces configured to be activated in three different circumstances:

- The load on the primary line reaches a certain threshold.

- The load on the primary line exceeds a specified threshold.

- The primary line goes down.

Dial Backup Using an Asynchronous Interface Example

The following is an example for dial backup using asynchronous interface 1, which is configured for DDR:

interface serial 0

ip address 172.30.3.4 255.255.255.0

backup interface async1

backup delay 10 10

!

interface async 1

ip address 172.30.3.5 255.255.255.0

dialer in-band

dialer string 5551212

dialer-group 1

async dynamic routing

dialer-list 1 protocol ip permit

chat-script sillyman "" “atdt 5551212” TIMEOUT 60 “CONNECT”

line 1

modem chat-script sillyman

modem inout

speed 9600

Dial Backup Using DDR and ISDN Example

The following example shows how to use an ISDN interface to back up a serial interface.

Note When you use a BRI interface for dial backup, neither of the B channels can be used while the interface is in standby mode.

Interface BRI 0 is configured to make outgoing calls to one number. This is a legacy DDR spoke example.

interface serial 1

backup delay 0 0

backup interface bri 0

ip address 10.2.3.4 255.255.255.0

!

interface bri 0

ip address 10.2.3.5 255.255.255.0

dialer string 5551212

dialer-group 1

!

dialer-list 1 protocol ip permit

Note Dialing will occur only after a packet is received to be output on BRI 0. We recommend using the dialer-list command with the protocol and permit keywords specified to control access for dial backup. Using this form of access control specifies that all packets are interesting.

Dial Backup Service When the Primary Line Reaches Threshold Example

The same example on a Cisco 7500 series router would be as follows:

interface serial 1/1

backup interface serial 2/2

backup load 75 5

Dial Backup Service When the Primary Line Exceeds Threshold Example

The following example configures the secondary line (serial 1) to activate when the traffic threshold on the primary line exceeds 25 percent:

interface serial 0

backup interface serial 1

backup load 25 5

backup delay 10 60

When the aggregate load of the primary and the secondary lines returns to within 5 percent of the primary bandwidth, the secondary line is deactivated. The secondary line waits 10 seconds after the primary goes down before activating and remains active for 60 seconds after the primary returns and becomes active again.

The same example on a Cisco 7500 series router would be as follows:

interface serial 1/0

backup interface serial 2/0

backup load 25 5

backup delay 10 60

Dial Backup Service When the Primary Line Goes Down Example

The following example configures the secondary line (serial 1) as a backup line that becomes active only when the primary line (serial 0) goes down. The backup line will not be activated because of load on the primary line.

interface serial 0

backup interface serial 1

backup delay 30 60

The backup line is configured to activate 30 seconds after the primary line goes down and to remain on for 60 seconds after the primary line is reactivated.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2001–2009 Cisco Systems, Inc. All rights reserved.

Configuring Dial Backup with Dialer Profiles

This chapter describes how to configure dialer interfaces, which can be configured as the logical intermediary between one or more physical interfaces and another physical interface that is to function as backup. It includes the following main sections:

- Dial Backup with Dialer Profiles Overview

- How to Configure Dial Backup with Dialer Profiles

- Configuration Example of Dialer Profile for ISDN BRI Backing Up Two Leased Lines

To identify the hardware platform or software image information associated with a feature, use the Feature Navigator on Cisco.com to search for information about the feature or refer to the software release notes for a specific release. For more information, see the “Identifying Supported Platforms” section in the “Using Cisco IOS Software” chapter.

For a complete description of the dial backup commands in this chapter, refer to the Cisco IOS Dial Technologies Command Reference. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

Dial Backup with Dialer Profiles Overview

A backup interface is an interface that stays idle until certain circumstances occur; then it is activated. Dialer interfaces can be configured to use a specific dialing pool; in turn, physical interfaces can be configured to belong to the same dialing pool.

See the section “Configuration Example of Dialer Profile for ISDN BRI Backing Up Two Leased Lines” at the end of this chapter for a comprehensive example of a dial backup interface using dialer profiles. In the example, one BRI functions as backup to two serial lines and can make calls to two different destinations.

How to Configure Dial Backup with Dialer Profiles

To configure a dialer interface and a specific physical interface to function as backup to other physical interfaces, perform the tasks in the following sections:

- Configuring a Dialer Interface (Required)

- Configuring a Physical Interface to Function As Backup (Required)

- Configuring Interfaces to Use a Backup Interface (Required)

Configuring a Dialer Interface

Command

Purpose

Step 1

Router(config)# interface dialer number

Creates a dialer interface and begins interface configuration mode.

Step 2

Router(config-if)# ip unnumbered loopback0

Specifies IP unnumbered loopback.

Step 3

Router(config-if)# encapsulation ppp

Specifies PPP encapsulation.

Step 4

Router(config-if)# dialer remote-name username

Specifies the Challenge Handshake Authentication Protocol (CHAP) authentication name of the remote router.

Step 5

Router(config-if)# dialer string dial-string

Specifies the remote destination to call.

Step 6

Router(config-if)# dialer pool number

Specifies the dialing pool to use for calls to this destination.

Step 7

Router(config-if)# dialer-group group-number

Assigns the dialer interface to a dialer group.

Configuring a Physical Interface to Function As Backup

To configure the physical interface that is to function as backup, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# interface type number

Specifies the interface and begins interface configuration mode.

Step 2

Router(config-if)# encapsulation ppp

Specifies PPP encapsulation.

Step 3

Router(config-if)# dialer pool-member number

Makes the interface a member of the dialing pool that the dialer interface will use; make sure the number arguments have the same value.

Step 4

Router(config-if)# ppp authentication chap

Specifies CHAP authentication.

Configuring Interfaces to Use a Backup Interface

To configure one or more interfaces to use a backup interface, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# interface type number

Specifies the interface to be backed up and begins interface configuration mode.

Step 2

Router(config-if)# ip unnumbered loopback0

Specifies IP unnumbered loopback.

Step 3

Router(config-if)# backup interface dialer number

Specifies the backup interface and begins interface configuration mode.

Step 4

Router(config-if)# backup delay enable-delay disable-delay

Specifies delay between the physical interface going down and the backup being enabled, and between the physical interface coming back up and the backup being disabled.

Configuration Example of Dialer Profile for ISDN BRI Backing Up Two Leased Lines

The following example shows the configuration of a site that backs up two leased lines using one BRI. Two dialer interfaces are defined. Each serial (leased line) interface is configured to use one of the dialer interfaces as a backup. Both of the dialer interfaces use dialer pool 1, which has physical interface BRI 0 as a member. Thus, physical interface BRI 0 can back up two different serial interfaces and can make calls to two different sites.

interface dialer0

ip unnumbered loopback0

encapsulation ppp

dialer remote-name Remote0

dialer pool 1

dialer string 5551212

dialer-group 1

interface dialer1

ip unnumbered loopback0

encapsulation ppp

dialer remote-name Remote1

dialer pool 1

dialer string 5551234

dialer-group 1

interface bri 0

encapsulation PPP

dialer pool-member 1

ppp authentication chap

interface serial 0

ip unnumbered loopback0

backup interface dialer 0

backup delay 5 10

interface serial 1

ip unnumbered loopback0

backup interface dialer1

backup delay 5 10

Dialer Watch Connect Delay

Feature History

Release

Modification

12.2(8)T

This feature was introduced.

This document describes the Dialer Watch Connect Delay feature in Cisco IOS Release 12.2(8)T and includes the following sections:

- Feature Overview

- Supported Platforms

- Supported Standards, MIBs, and RFCs

- Prerequisites

- Configuration Tasks

- Verifying Dialer Watch Connect Delay Configuration

- Configuration Examples

- Command Reference

Feature Overview

The Dialer Watch Connect Delay feature introduces the ability to configure a delay in bringing up a secondary link when a primary link that is monitored by Dialer Watch goes down and is removed from the routing table. Previously, the router would instantly dial a secondary route without allowing time for the primary route to come back up. When the Dialer Watch Connect Delay feature is configured, the router will check for availability of the primary link at the end of the specified delay time before dialing the secondary link.

Benefits

The Dialer Watch Connect Delay feature allows users greater control over the use of a secondary link on monitored IP addresses or networks. Configuring the router to delay bringing up a secondary link when the watched primary link goes down will allow time for the primary link to be restored in the event of a temporary outage.

Related Documents

- The part “ Dial-on-Demand Routing Configuration ” in the Cisco IOS Dial Technologies Configuration Guide, Release 12.2.

- The chapter “ Configuring Dial Backup Using Dialer Watch ” in the Cisco IOS Dial Technologies Configuration Guide, Release 12.2.

- Cisco IOS Dial Technologies Command Reference , Release 12.2

Supported Platforms

- Cisco 805

- Cisco 806

- Cisco 820

- Cisco 827

- Cisco 828

- Cisco 1600 series

- Cisco 1700

- Cisco 1710

- Cisco 2600 series

- Cisco 3640

- Cisco 3660

- Cisco 7100

- Cisco 7200

- Cisco 7500

- soho 78

- mc3810

- C6MSFC2

Determining Platform Support Through Cisco Feature Navigator

Cisco IOS software is packaged in feature sets that support specific platforms. To get updated information regarding platform support for this feature, access Cisco Feature Navigator. Cisco Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.

Cisco Feature Navigator is a web-based tool that enables you to quickly determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image. You can search by feature or release. Under the release section, you can compare releases side by side to display both the features unique to each software release and the features in common.

To access Cisco Feature Navigator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions at http://www.cisco.com/register.

Cisco Feature Navigator is updated regularly when major Cisco IOS software releases and technology releases occur. For the most current information, go to the Cisco Feature Navigator home page at the following URL:

http://www.cisco.com/go/fn

Supported Standards, MIBs, and RFCs

Standards

No new or modified standards are supported by this feature.

MIBs

No new or modified MIBs are supported by this feature.

To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

RFCs

No new or modified RFCs are supported by this feature.

Prerequisites

Dial-on-Demand routing (DDR) must be configured and Dialer Watch must be enabled. For more information on configuring DDR, refer to the following documents:

- The part “ Dial-on-Demand Routing Configuration ” in the Cisco IOS Dial Technologies Configuration Guide, Release 12.2.

- The chapter “ Configuring Dial Backup Using Dialer Watch ” in the Cisco IOS Dial Technologies Configuration Guide, Release 12.2.

Configuration Tasks

See the following sections for configuration tasks for the Dialer Watch Connect Delay feature. Each task in the list is identified as either required or optional.

- Configuring a Delay Before Activating a Secondary Link (required)

- Configuring a Delay Before Disconnecting the Secondary Link (optional)

Configuring a Delay Before Activating a Secondary Link

To configure the router to delay before dialing a secondary link when the primary link goes down, use the following command in global configuration mode:

Command

Purpose

Router(config)# dialer watch-list group-number delay connect connect-time

Configures a delay in dialing the secondary link when the primary link becomes unavailable.

- The delay connect keyword phrase specifies that the router will delay dialing the secondary link when the primary link becomes unavailable.

- The connect-time argument specifies the time, in seconds, after which the router rechecks for availability of the primary link. If the primary link is still unavailable, the secondary link is then dialed. Valid times range from 1 to 2147483.

Configuring a Delay Before Disconnecting the Secondary Link

To configure the router to delay before disconnecting a secondary link when the primary link is reestablished, use the following command in global configuration mode:

Command

Purpose

Router(config)# dialer watch-list group-number delay disconnect disconnect-time

Configures a delay in disconnecting the secondary link after detecting availability of the primary link.

- The delay disconnect keyword phrase specifies that the router will delay disconnecting the secondary link after detecting availability of the primary link.

- The disconnect-time argument specifies the time, in seconds, after which the router disconnects the secondary link once the primary link has been detected. Valid times range from 1 to 2147483.

Verifying Dialer Watch Connect Delay Configuration

To verify the cofiguration fo the Dialer Watch Connect Delay feature, perform the following steps:

Step 1 Enter the show running-config command to verify the configuration of Dialer Watch connect and disconnect delays:

router# show running-config

dialer watch-list 1 ip 10.1.1.1 255.0.0.0

dialer watch-list 1 delay connect 20

dialer watch-list 1 delay disconnect 20

dialer-list 1 protocol ip permit

Step 2 Enter the debug dialer command:

router# debug dialer

Connect Delay

------------------------

*Mar 1 04:29:16:DDR:Dialer Watch:watch-group = 1

*Mar 1 04:29:16:DDR: network 5.0.0.0/255.0.0.0 DOWN,

*Mar 1 04:29:16:DDR: network 4.0.0.0/255.0.0.0 DOWN,

*Mar 1 04:29:16:DDR: network 3.0.0.0/255.0.0.0 DOWN,

*Mar 1 04:29:16:DDR: primary DOWN

*Mar 1 04:29:16:DDR:Dialer Watch: Primary of group 1 DOWN - start dial-backup timer

Disconnect delay

------------------------

*Mar 1 04:31:11:BR2/0:1 DDR:idle timeout

*Mar 1 04:31:11:DDR:Dialer Watch:watch-group = 1

*Mar 1 04:31:11:DDR: network 5.0.0.0/255.0.0.0 UP,

*Mar 1 04:31:11:DDR: primary UP

*Mar 1 04:31:11:BR2/0:1 DDR:starting watch disconnect timer

*Mar 1 04:31:46:BR2/0:1 DDR:watch disconnect timeout

*Mar 1 04:31:46:DDR:Dialer Watch:watch-group = 1

*Mar 1 04:31:46:DDR: network 5.0.0.0/255.0.0.0 UP,

*Mar 1 04:31:46:DDR: primary UP

Configuration Examples

This section provides the following configuration examples:

- Configuring a Delay Before Activating a Secondary Link Example

- Configuring a Delay Before Disconnecting a Secondary Link Example

Configuring a Delay Before Activating a Secondary Link Example

The following example configures the router to wait 10 seconds before verifying that the primary link is still down and dialing a secondary link:

dialer watch-list 1 ip 10.1.1.0 255.255.255.0

dialer watch-list 1 delay connect 10

Configuring a Delay Before Disconnecting a Secondary Link Example

- dialer watch-list delay

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2007-2008 Cisco Systems, Inc. All rights reserved.

Configuring Cisco Easy IP

This chapter describes how to configure the Cisco Easy IP feature. It includes the following main sections:

- Cisco Easy IP Overview

- How to Configure Cisco Easy IP

- Configuration Examples for Cisco Easy IP

To identify the hardware platform or software image information associated with a feature, use the Feature Navigator on Cisco.com to search for information about the feature or refer to the software release notes for a specific release. For more information, see the “Identifying Supported Platforms” section in the “Using Cisco IOS Software” chapter.

For a complete description of the Cisco Easy IP commands in this chapter, refer to the Cisco IOS Dial Technologies Command Reference. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

Cisco Easy IP Overview

Cisco Easy IP enables transparent and dynamic IP address allocation for hosts in remote environments using the following functionality:

- Cisco Dynamic Host Configuration Protocol (DHCP) server

- Port Address Translation (PAT), a subset of Network Address Translation (NAT)

- Dynamic PPP/IP Control Protocol (PPP/IPCP) WAN interface IP address negotiation

With the Cisco IOS Easy IP, a Cisco router automatically assigns local IP addresses to remote hosts (such as small office, home office or SOHO routers) using DHCP with the Cisco IOS DHCP server, automatically negotiates its own registered IP address from a central server via PPP/IPCP, and uses PAT functionality to enable all SOHO hosts to access the Internet using a single registered IP address. Because Cisco IOS Easy IP uses existing port-level multiplexed NAT functionality within Cisco IOS software, IP addresses on the remote LAN are invisible to the Internet, making the remote LAN more secure.

Cisco Easy IP provides the following benefits:

- Minimizes Internet access costs for remote offices

- Minimizes configuration requirements on remote access routers

- Enables transparent and dynamic IP address allocation for hosts in remote environments

- Improves network security capabilities at each remote site

- Conserves registered IP addresses

- Maximizes IP address manageability

Figure 1 shows a typical scenario for using the Cisco Easy IP feature.

Figure 1 Telecommuter and Branch Office LANs Using Cisco Easy IP

Steps 1 through 4 show how Cisco Easy IP works:

Step 1 When a SOHO host generates “interesting” traffic (as defined by Access Control Lists) for dialup (first time only), the Easy IP router requests a single registered IP address from the access server at the central site via PPP/IPCP. (See Figure 2.)

Figure 2 Cisco Easy IP Router Requests a Dynamic Global IP Address

Step 2 The central site router replies with a dynamic global address from a local DHCP IP address pool. (See Figure 3.)

Figure 3 Dynamic Global IP Address Delivered to the Cisco Easy IP Router

Figure 4 Port-Level NAT Functionality Used for IP Address Translation

Figure 5 Multiple Private Internal IP Addresses Bound to a Single Global IP Address

How to Configure Cisco Easy IP

Before using Cisco Easy IP, perform the following tasks:

- Configure the ISDN switch type and service provider identifier (SPID), if using ISDN.

- Configure the static route from LAN to WAN interface.

- Configure the Cisco IOS DHCP server.

For information about configuring ISDN switch types, see the chapter “Setting Up ISDN Basic Rate Service” earlier in this publication. For information about configuring static routes, refer to the chapter “Configuring IP Services” in the Cisco IOS IP Configuration Guide.

The Cisco IOS DHCP server supports both DHCP and BOOTP clients and supports finite and infinite address lease periods. DHCP address binding information is stored on a remote host via remote copy protocol (RCP), FTP, or TFTP. Refer to the Cisco IOS IP Configuration Guide for DHCP configuration instructions.

In its most simple configuration, a Cisco Easy IP router or access server will have a single LAN interface and a single WAN interface. Based on this model, to use Cisco Easy IP you must perform the tasks in the following sections:

- Defining the NAT Pool (Required)

- Configuring the LAN Interface (Required)

- Defining NAT for the LAN Interface (Required)

- Configuring the WAN Interface (Required)

- Enabling PPP/IPCP Negotiation (Required)

- Defining NAT for the Dialer Interface (Required)

- Configuring the Dialer Interface (Required)

For configuration examples, see the section “Configuration Examples for Cisco Easy IP” at the end of this chapter.

Defining the NAT Pool

The first step in enabling Cisco Easy IP is to create a pool of internal IP addresses to be translated. To define the NAT pool, use the following commands in global configuration mode:

Command

Purpose

Step 1

Router(config)# access-list access-list-number permit source [source-wildcard]

Defines a standard access list permitting those addresses that are to be translated.

Step 2

Router(config)# ip nat inside source list access-list-number interface dialer-name overload

Establishes dynamic source translation, identifying the access list defined in the prior step.

For information about creating access lists, refer to the chapter “Configuring IP Services” in the Cisco IOS IP Configuration Guide.

Configuring the LAN Interface

Command

Purpose

Step 1

Router(config)# interface type number

Selects a specific LAN interface and begins interface configuration mode.

Step 2

Router(config-if)# ip address address mask

Defines the IP address and subnet mask for this interface.

For information about assigning IP addresses and subnet masks to network interfaces, refer to the chapter “Configuring IP Services” in the Cisco IOS IP Configuration Guide.

Defining NAT for the LAN Interface

Command

Purpose

Router(config-if)# ip nat inside

Defines the interface as internal for NAT.

Configuring the WAN Interface

To configure the WAN interface, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# interface type number

Selects the WAN interface and begins interface configuration mode.

Step 2

Router(config-if)# no ip address

Removes any associated IP address from this interface.

Step 3

Router(config-if)# encapsulation ppp

Selects PPP as the encapsulation method for this interface.

Step 4

Router(config-if)# dialer pool-member number

Binds the WAN interface to the dialer interface.

Enabling PPP/IPCP Negotiation

To enable PPP/IPCP negotiation on the dialer interface, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# interface dialer-name

Selects the dialer interface and begins interface configuration mode.

Step 2

Router(config-if)# ip address negotiated

Enables PPP/IPCP negotiation for this interface.

Defining NAT for the Dialer Interface

To define that the dialer interface is connected to the outside network, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# interface dialer-name

Selects the dialer interface and begins interface configuration mode.

Step 2

Router(config-if)# ip nat outside

Defines the interface as external for network address translation.

Configuring the Dialer Interface

To configure the dialer interface information, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# interface dialer-name

Selects the dialer interface and begins interface configuration mode.

Step 2

Router(config-if)# dialer wait-for-carrier-time seconds

Specifies for a dialer interface the length of time the interface waits for a carrier before timing out.

Step 3

Router(config-if)# dialer hold-queue packets

Creates a dialer hold queue and specifies the number of packets to be held in it.

Step 4

Router(config-if)# dialer remote-name username

Specifies the remote router Challenge Handshake Authentication Protocol (CHAP) authentication name.

Step 5

Router(config-if)# dialer idle-timeout seconds

Specifies the amount of idle time that can pass before calls to the central access server are disconnected. See the next section “Timeout Considerations,” for more details on this setting.

Step 6

Router(config-if)# dialer string dialer-string

Specifies the telephone number required to reach the central access server.

Step 7

Router(config-if)# dialer pool number

Specifies the dialing pool to use.

Step 8

Router(config-if)# dialer-group group-number

Assigns the dialer interface to a dialer group.

Timeout Considerations

Dynamic NAT translations time out automatically after a predefined default period. Although configurable, with the port-level NAT functionality in Cisco Easy IP, Domain Name System (DNS) User Datagram Protocol (UDP) translations time out after 5 minutes, while DNS translations time out after 1 minute by default. TCP translations time out after 24 hours by default, unless a TCP Reset (RST) or TCP Finish (FIN) is seen in the TCP stream, in which case the translation times out after 1 minute.

If the Cisco IOS Easy IP router exceeds the dialer idle-timeout period, it is expected that all active TCP sessions were previously closed via an RST or FIN. NAT times out all TCP translations before the Cisco Easy IP router exceeds the dialer idle-timeout period. The router then renegotiates another registered IP address the next time the WAN link is brought up, thereby creating new dynamic NAT translations that bind the IP addresses of the LAN host to the newly negotiated IP address.

Configuration Examples for Cisco Easy IP

The following example shows how to configure BRI interface 0 (shown as interface bri0) to obtain its IP address via PPP/IPCP address negotiation:

! The following command defines the NAT pool.

ip nat inside source list 101 interface dialer1 overload

!

! The following commands define the ISDN switch type.

isdn switch type vn3

isdn tei-negotiation first-call

!

! The following commands define the LAN address and subnet mask.

interface ethernet0

ip address 10.0.0.4 255.0.0.0

! The following command defines ethernet0 as internal for NAT.

ip nat inside

!

! The following commands binds the physical interface to the dialer1 interface.

interface bri0

no ip address

encapsulation ppp

dialer pool-member 1

!

interface dialer1

!

! The following command enables PPP/IPCP negotiation for this interface.

ip address negotiated

encapsulation ppp

!

! The following command defines interface dialer1 as external for NAT.

ip nat outside

dialer remote-name dallas

dialer idle-timeout 180

!

! The following command defines the dialer string for the central access server.

dialer string 4159991234

dialer pool 1

dialer-group 1

!

! The following commands define the static route to the WAN interface.

ip route 0.0.0.0 0.0.0.0 dialer1

access-list 101 permit ip 10.0.0.0 0.255.255.255 any

dialer-list 1 protocol ip list 101

The following example shows how to configure an asynchronous interface (interface async1) to obtain its IP address via PPP/IPCP address negotiation:

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

.Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2007–2009 Cisco Systems, Inc. All rights reserved.

Configuring Virtual Profiles

First Published: December 15, 1997

Last Updated: November 20, 2014

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the “Feature Information for Configuring Virtual Profiles” section.

Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Contents

- Prerequisites for Configuring Virtual Profiles

- Information About Configuring Virtual Profiles

- How to Configure Virtual Profiles

- Configuration Examples for Virtual Profiles

- Additional References

- Feature Information for Configuring Virtual Profiles

Prerequisites for Configuring Virtual Profiles

Cisco recommends that unnumbered addresses be used in virtual template interfaces to ensure that duplicate network addresses are not created on virtual access interfaces (VAIs).

Restrictions for Configuring Virtual Profiles

The virtual-profile command was removed from Cisco IOS Release 12.2(34)SB and 12.2(33)XNE, because Cisco 10000 series routers do not support the full VAIs these releases create and configuration errors could occur.

Information About Configuring Virtual Profiles

This section provides information about virtual profiles for use with virtual access interfaces and how virtual profiles work. Virtual profiles run on all Cisco IOS platforms that support Multilink PPP (MLP). Virtual profiles interoperate with Cisco dial-on-demand routing (DDR), MLP, and dialers such as ISDN. To configure virtual profiles, you should understand the following concepts:

- Virtual Profiles Overview

- How Virtual Profiles Work—Four Configuration Cases

Virtual Profiles Overview

Virtual profiles support these encapsulation methods:

- PPP

- MLP

- High-Level Data Link Control (HDLC)

- Link Access Procedure, Balanced (LAPB)

- X.25

- Frame Relay

Any commands for these encapsulations that can be configured under a serial interface can be configured under a virtual profile stored in a user file on an authentication, authorization, and accounting (AAA) server and a virtual profile virtual template configured locally. The AAA server daemon downloads them as text to the network access server and is able to handle multiple download attempts.

The configuration information for a virtual profiles virtual access interface can come from a virtual template interface or from user-specific configuration stored on a AAA server, or both.

If a B interface is bound by the calling line identification (CLID) to a created virtual access interface cloned from a virtual profile or a virtual template interface, only the configuration from the virtual profile or the virtual template takes effect. The configuration on the D interface is ignored unless successful binding occurs by PPP name. Both the link and network protocols run on the virtual access interface instead of the B channel, unless the encapsulation is PPP.

Moreover, in previous releases of Cisco IOS software, downloading a profile from an AAA server and creating and cloning a virtual access interface was always done after the PPP call answer and link control protocol (LCP) up processes. The AAA download is part of authorization. But in the current release, these operations must be performed before the call is answered and the link protocol goes up. This restriction is a new AAA nonauthenticated authorization step. The virtual profile code handles multiple download attempts and identifies whether a virtual access interface was cloned from a downloaded virtual profile.

When a successful download is done through nonauthenticated authorization and the configuration on the virtual profile has encapsulation PPP and PPP authentication, authentication is negotiated as a separate step after LCP comes up.

The per-user configuration feature also uses configuration information gained from a AAA server. However, per-user configuration uses network configurations (such as access lists and route filters) downloaded during Network Control Protocol (NCP) negotiations.

Two rules govern virtual access interface configuration by virtual profiles, virtual template interfaces, and AAA configurations:

- Each virtual access application can have at most one template to clone from but can have multiple AAA configurations to clone from (virtual profiles AAA information and AAA per-user configuration, which in turn might include configuration for multiple protocols).

- When virtual profiles are configured by virtual template, its template has higher priority than any other virtual template.

DDR Configuration of Physical Interfaces

Virtual profiles fully interoperate with physical interfaces in the following DDR configuration states when no other virtual access interface application is configured:

- Dialer profiles are configured for the interface—The dialer profile is used instead of the virtual profiles configuration.

- DDR is not configured on the interface—Virtual profiles overrides the current configuration.

- Legacy DDR is configured on the interface—Virtual profiles overrides the current configuration.

Note If a dialer interface is used (including any ISDN dialer), its configuration is used on the physical interface instead of the virtual profiles configuration.

Multilink PPP Effect on Virtual Access Interface Configuration

As shown in Table 1, exactly how a virtual access interface will be configured depends on the following three factors:

- Whether virtual profiles are configured by a virtual template, by AAA, by both, or by neither. In the table, these states are shown as “VP VT only,” “VP AAA only,” “VP VT and VP AAA,” and “No VP at all,” respectively.

- The presence or absence of a dialer interface.

- The presence or absence of MLP. The column label “MLP” is a stand-in for any virtual access feature that supports MLP and clones from a virtual template interface.

In Table 1, “(Multilink VT)” means that a virtual template interface is cloned if one is defined for MLP or a virtual access feature that uses MLP.

Table 1 Virtual Profiles Configuration Cloning Sequence

Virtual Profiles Configuration

MLP

No Dialer

MLP

Dialer

No MLP

No Dialer

No MLP

Dialer

VP VT only

VP VT

VP VT

VP VT

VP VT

VP AAA only

(Multilink VT)

VP AAA

(Multilink VT)

VP AAA

VP AAA

VP AAA

VP VT and VP AAA

VP VT

VP AAA

VP VT

VP AAA

VP VT

VP AAA

VP VT

VP AAA

No VP at all

(Multilink VT)1

Dialer2

No virtual access interface is created.

No virtual access interface is created.

1.The multilink bundle virtual access interface is created and uses the default settings for MLP or the relevant virtual access feature that uses MLP.

2.The multilink bundle virtual access interface is created and cloned from the dialer interface configuration.

The order of items in any cell of the table is important. Where VP VT is shown above VP AAA, it means that first the virtual profile virtual template is cloned on the interface, and then the AAA interface configuration for the user is applied to it. The user-specific AAA interface configuration adds to the configuration and overrides any conflicting physical interface or virtual template configuration commands.

Interoperability with Other Features That Use Virtual Templates

Virtual profiles also interoperate with virtual access applications that clone a virtual template interface. Each virtual access application can have at most one template to clone from but can clone from multiple AAA configurations.

The interaction between virtual profiles and other virtual template applications is as follows:

- If virtual profiles are enabled and a virtual template is defined for it, the virtual profile virtual template is used.

- If virtual profiles are configured by AAA alone (no virtual template is defined for virtual profiles), the virtual template for another virtual access application (virtual private dialup networks or VPDNs, for example) can be cloned onto the virtual access interface.

- A virtual template, if any, is cloned to a virtual access interface before the virtual profiles AAA configuration or AAA per-user configuration. AAA per-user configuration, if used, is applied last.

How Virtual Profiles Work—Four Configuration Cases

This section describes virtual profiles and the various ways that they can work with virtual template interfaces, user-specific AAA interface configuration, and MLP or another feature that requires MLP.

Virtual profiles separate configuration information into two logical parts:

- Generic—Common configuration for dial-in users plus other router-dependent configuration. This common and router-dependent information can define a virtual template interface stored locally on the router. The generic virtual template interface is independent of and can override the configuration of the physical interface on which a user dialed in.

- User-specific interface information—Interface configuration stored in a user file on an AAA server; for example, the authentication requirements and specific interface settings for a specific user. The settings are sent to the router in the response to the request from the router to authenticate the user, and the settings can override the generic configuration. This process is explained more in the section “Virtual Profiles Configured by AAA” later in this chapter.

These logical parts can be used separately or together. Four separate cases are possible:

- Case 1: Virtual Profiles Configured by Virtual Template—Applies the virtual template.

- Case 2: Virtual Profiles Configured by AAA—Applies the user-specific interface configuration received from the AAA server.

- Case 3: Virtual Profiles Configured by Virtual Template and AAA Configuration—Applies the virtual template and the user-specific interface configuration received from the AAA server.

- Case 4: Virtual Profiles Configured by AAA, and a Virtual Template Defined by Another Application—Applies the other application’s virtual template interface and then applies the user-specific interface configuration received from the AAA server.

Note All cases assume that AAA is configured globally on the router, that the user has configuration information in the user file on the AAA server, that PPP authentication and authorization proceed as usual, and that the AAA server sends user-specific configuration information in the authorization approval response packet to the router.

The cases also assume that AAA works as designed and that the AAA server sends configuration information for the dial-in user to the router, even when virtual profiles by virtual template are configured.

Case 1: Virtual Profiles Configured by Virtual Template

In the case of virtual profiles configured by virtual template, the software functions as follows:

- If the physical interface is configured for dialer profiles (a DDR feature), the router looks for a dialer profile for the specific user.

- If a dialer profile is found, it is used instead of virtual profiles.

- If a dialer profile is not found for the user, or legacy DDR is configured, or DDR is not configured at all, virtual profiles create a virtual access interface for the user.

The router applies the configuration commands that are in the virtual template interface to create and configure the virtual profile. The template includes generic interface information and router-specific information, but no user-specific information. No matter whether a user dialed in on a synchronous serial, an asynchronous serial, or an ISDN interface, the dynamically created virtual profile for the user is configured as specified in the virtual template.

Then the router interprets the lines in the AAA authorization approval response from the server as Cisco IOS commands to apply to the virtual profile for the user.

Data flows through the virtual profile, and the higher layers treat it as the interface for the user.

For example, if a virtual template included only the three commands ip unnumbered ethernet 0, encapsulation ppp, and ppp authentication chap, the virtual profile for any dial-in user would include those three commands.

In Figure 1, the dotted box represents the virtual profile configured with the commands that are in the virtual template, no matter which interface the call arrives on.

Figure 1 Virtual Profiles by Virtual Template

See the “Configuring Virtual Profiles by Virtual Template” section for configuration tasks for this case.

Case 2: Virtual Profiles Configured by AAA

In this case, no dialer profile (a DDR feature) is defined for the specific user and no virtual template for virtual profiles is defined, but virtual profiles by AAA are enabled on the router.

During the PPP authorization phase for the user, the AAA server responds as usual to the router. The authorization approval contains configuration information for the user. The router interprets each of the lines in the AAA response from the server as Cisco IOS commands to apply to the virtual profile for the user.

Note If MLP is negotiated, the MLP virtual template is cloned first (this is the second row), and then interface-specific commands included in the AAA response from the server for the user are applied. The MLP virtual template overrides any conflicting interface configuration, and the AAA interface configuration overrides any conflicting configuration from both the physical interface and the MLP virtual template.

The router applies all the user-specific interface commands received from the AAA server.

Suppose, for example, that the router interpreted the response by the AAA server as including only the following two commands for this user:

ip address 10.10.10.10 255.255.255.255

keepalive 30

In Figure 2, the dotted box represents the virtual profile configured only with the commands received from the AAA server, no matter which interface the incoming call arrived on. On the AAA RADIUS server, the attribute-value (AV) pair might have read as follows, where “\n” means to start a new command line:

cisco-avpair = “lcp:interface-config=ip address 10.10.10.10 255.255.255.0\nkeepalive 30”,

Figure 2 Virtual Profiles by AAA Configuration

See the “Configuring Virtual Profiles by AAA Configuration” section for configuration tasks for this case.

Case 3: Virtual Profiles Configured by Virtual Template and AAA Configuration

In this case, no DDR dialer profile is defined for the specific user, a virtual template for virtual profiles is defined, virtual profiles by AAA is enabled on the router, the router is configured for AAA, and a user-specific interface configuration for the user is stored on the AAA server.

The router performs the following tasks in order:

1. Dynamically creates a virtual access interface cloned from the virtual template defined for virtual profiles.

2. Applies the user-specific interface configuration received from the AAA server.

If any command in the user’s configuration conflicts with a command on the original interface or a command applied by cloning the virtual template, the user-specific command overrides the other command.

Suppose that the router had the virtual template as defined in Case 1 and the AAA user configuration as defined in Case 2. In Figure 3 the dotted box represents the virtual profile configured with configuration information from both sources, no matter which interface the incoming call arrived on. The ip address command has overridden the ip unnumbered command.

Figure 3 Virtual Profiles by Both Virtual Template and AAA Configuration

See the “Configuring Virtual Profiles by Both Virtual Template and AAA Configuration” section for configuration tasks for this case.

Case 4: Virtual Profiles Configured by AAA, and a Virtual Template Defined by Another Application

In this case, no DDR dialer profile is defined for the specific user, virtual profiles by AAA are configured on the router but no virtual template is defined for virtual profiles, and a user-specific interface configuration is stored on the AAA server. In addition, a virtual template is configured for some other virtual access application (a VPDN, for example).

The router performs the following tasks in order:

1. Dynamically creates a virtual access interface and clones the virtual template from the other virtual access application onto it.

2. Applies the user-specific interface configuration received from the AAA server.

If any command in the virtual template conflicts with a command on the original interface, the template overrides it.

If any command in the AAA interface configuration for the user conflicts with a command in the virtual template, the user AAA interface configuration conflicts will override the virtual template.

If per-user configuration is also configured on the AAA server, that network protocol configuration is applied to the virtual access interface last.

The result is a virtual interface unique to that user.

How to Configure Virtual Profiles

To configure virtual profiles for dial-in users, perform the tasks in one of the first three sections and then troubleshoot the configuration by performing the tasks in the last section:

- Configuring Virtual Profiles by Virtual Template (as required)

- Configuring Virtual Profiles by AAA Configuration (as required)

- Configuring Virtual Profiles by Both Virtual Template and AAA Configuration (as required)

- Troubleshooting Virtual Profile Configurations (as required)

Note Do not define a DDR dialer profile for a user if you intend to define virtual profiles for the user.

Configuring Virtual Profiles by Virtual Template

To configure virtual profiles by virtual template, complete these two tasks:

- Creating and Configuring a Virtual Template Interface

- Specifying a Virtual Template Interface for Virtual Profiles

Note The order in which these tasks is performed is not crucial. However, both tasks must be completed before virtual profiles are used.

Creating and Configuring a Virtual Template Interface

Because a virtual template interface is a serial interface, all the configuration commands that apply to serial interfaces can also be applied to virtual template interfaces, except shutdown and dialer commands.

To create and configure a virtual template interface, use the following commands:

Command

Purpose

Step 1

Router(config)# interface virtual-template number

Creates a virtual template interface and enters interface configuration mode.

Step 2

Router(config-if)# ip unnumbered ethernet 0

Enables IP without assigning a specific IP address on the LAN.

Step 3

Router(config-if)# encapsulation ppp

Enables PPP encapsulation on the virtual template interface.

Other optional PPP configuration commands can be added to the virtual template configuration. For example, you can add the ppp authentication chap command.

Specifying a Virtual Template Interface for Virtual Profiles

Command

Purpose

Router(config)# virtual-profile virtual-template number

Specifies the virtual template interface as the source of information for virtual profiles.

Virtual template numbers range from 1 to 25.

Configuring Virtual Profiles by AAA Configuration

To configure virtual profiles by AAA only, complete these three tasks in any order. All tasks must be completed before virtual profiles are used.

- On the AAA server, create user-specific interface configurations for each of the specific users to use this method. See your AAA server documentation for more detailed configuration information about your AAA server.

- Configure AAA on the router, as described in the Cisco IOS Security Configuration Guide .

- Specify AAA as the source of information for virtual profiles.

To specify AAA as the source of information for virtual profiles, use the following command:

Command

Purpose

Router(config)# virtual-profile aaa

command is not available in Cisco IOS software. In releases later than Cisco IOS Release 12.2, the router automatically creates virtual profiles when AAA attributes require a profile.

Specifies AAA as the source of user-specific interface configuration.

If you also want to use per-user configuration for network protocol access lists or route filters for individual users, see the chapter “Configuring Per-User Configuration” in this publication. In this case, no virtual template interface is defined for virtual profiles.

Configuring Virtual Profiles by Both Virtual Template and AAA Configuration

cisco-avpair = “lcp:interface-config=ip address 192.168.200.200 255.255.255.0”,

Use of a virtual template interface with virtual profiles requires a virtual template to be defined specifically for virtual profiles.

To configure virtual profiles by both virtual template interface and AAA configuration, complete the following tasks in any order. All tasks must be completed before virtual profiles are used.

- On the AAA server, create user-specific interface configurations for each of the specific users to use this method. See your AAA server documentation for more detailed configuration information about your AAA server.

- Configure AAA on the router, as described in the Cisco IOS Security Configuration Guide publication.

- Creating and configuring a virtual template interface, described later in this chapter.

- Specifying virtual profiles by both virtual templates and AAA, described later in this chapter.

Creating and Configuring a Virtual Template Interface

To create and configure a virtual template interface, use the following commands:

Command

Purpose

Step 1

Router(config)# interface virtual-template number

Creates a virtual template interface and enters interface configuration mode.

Step 2

Router(config-if)# ip unnumbered ethernet 0

Enables IP without assigning a specific IP address on the LAN.

Step 3

Router(config-if)# encapsulation ppp

Enables PPP encapsulation on the virtual template interface.

Because the software treats a virtual template interface as a serial interface, all the configuration commands that apply to serial interfaces can also be applied to virtual template interfaces, except shutdown and dialer commands. Other optional PPP configuration commands can also be added to the virtual template configuration. For example, you can add the ppp authentication chap command.

Specifying Virtual Profiles by Both Virtual Templates and AAA

Command

Purpose

Step 1

Router(config)# virtual-profile virtual-template number

Defines the virtual template interface as the source of information for virtual profiles.

Step 2

Router(config)# virtual-profile aaa

Specifies AAA as the source of user-specific configuration for virtual profiles.

If you also want to use per-user configuration for network protocol access lists or route filters for individual users, see the Configuring per-User Configuration feature.

Troubleshooting Virtual Profile Configurations

Command

Purpose

Router# debug dialer

Displays information about dial calls and negotiations and virtual profile events.

Router# debug aaa per-user

Displays information about the per-user configuration downloaded from the AAA server.

Router# debug vtemplate cloning

Displays cloning information for a virtual access interface from the time it is cloned from a virtual template to the time it comes down.

Configuration Examples for Virtual Profiles

The following sections provide examples for the four cases described in this chapter:

- Virtual Profiles Configured by Virtual Templates: Example

- Virtual Profiles Configured by AAA Configuration: Example

- Virtual Profiles Configured by Virtual Templates and AAA Configuration: Example

- Virtual Profiles Configured by AAA Plus a VPDN Virtual Template on a VPDN Home Gateway: Example

In these examples, BRI 0 is configured for legacy DDR, and interface BRI 1 is configured for dialer profiles. Note that interface dialer 0 is configured for legacy DDR. Interface dialer 1 is a dialer profile.

The intention of the examples is to show how to configure virtual profiles. In addition, the examples show the interoperability of DDR and dialer profiles in the respective cases with various forms of virtual profiles.

The same user names (User1 and User2) occur in all these examples. Note the different configuration allowed to them in each of the four examples.

User1 is a normal user and can dial in to BRI 0 only. User2 is a privileged user who can dial in to BRI 0 and BRI 1. If User2 dials into BRI 1, the dialer profile will be used. If User2 dials into BRI 0, virtual profiles will be used. Because User1 does not have a dialer profile, only virtual profiles can be applied to User1.

To see an example of a configuration using virtual profiles and the Dynamic Multiple Encapsulations feature, see the “Multiple Encapsulations over ISDN” example in the chapter “Configuring Peer-to-Peer DDR with Dialer Profiles.”

Virtual Profiles Configured by Virtual Templates: Example

The following example shows a router configured for virtual profiles by virtual template. (Virtual profiles do not have any interface-specific AAA configuration.) Comments in the example draw attention to specific features or ignored lines.

In this example, the same virtual template interface applies to both users; they have the same interface configurations.

Router Configuration

! Enable AAA on the router.

aaa new-model

aaa authentication ppp default radius

! The following command is required.

aaa authorization network radius

enable secret 5 $1$koOn$/1QAylov6JFAElxRCrL.o/

enable password lab

!

! Specify configuration of virtual profiles by virtual template.

! This is the key command for this example.

virtual-profile virtual-template 1

!

! Define the virtual template.

interface Virtual-Template 1

ip unnumbered ethernet 0

encapsulation ppp

ppp authentication chap

!

switch-type basic-dms100

interface BRI 0

description Connected to 103

encapsulation ppp

no ip route-cache

dialer rotary-group 0

ppp authentication chap

!

interface BRI 1

description Connected to 104

encapsulation ppp

! Disable fast switching.

no ip route-cache

dialer pool-member 1

ppp authentication chap

!

! Configure dialer interface 0 for DDR for User1 and User2.

interface dialer 0

ip address 10.1.1.1 255.255.255.0

encapsulation ppp

! Enable legacy DDR.

dialer in-band

! Disable fast switching.

no ip route-cache

dialer map ip 10.1.1.2 name User1 1111

dialer map ip 10.1.1.3 name User2 2222

dialer-group 1

ppp authentication chap

!

! Configure dialer interface 1 for DDR to dial out to User2.

interface dialer 1

ip address 10.2.2.2 255.255.255.0

encapsulation ppp

dialer remote-name User2

dialer string 3333

dialer pool 1

dialer-group 1

! Disable fast switching.

no ip route-cache

ppp authentication chap

dialer-list 1 protocol ip permit

Virtual Profiles Configured by AAA Configuration: Example

The following example shows the router configuration for virtual profiles by AAA and the AAA server configuration for user-specific interface configurations. User1 and User2 have different IP addresses.

In the AAA configuration cisco-avpair lines, “\n” is used to indicate the start of a new Cisco IOS command line.

AAA Configuration for User1 and User2

User1 Password = "welcome"

User-Service-Type = Framed-User,

Framed-Protocol = PPP,

cisco-avpair = "lcp:interface-config=keepalive 75\nip address 192.16.100.100 255.255.255.0",

User2 Password = "emoclew"

User-Service-Type = Framed-User,

Framed-Protocol = PPP,

cisco-avpair = "lcp:interface-config=keepalive 100\nip address 192.168.200.200 255.255.255.0"

Router Configuration

! Enable AAA on the router.

aaa new-model

aaa authentication ppp default radius

! This is a key command for this example.

aaa authorization network radius

enable secret 5 $1$koOn$/1QAylov6JFAElxRCrL.o/

enable password lab

!

! Specify configuration of virtual profiles by aaa.

! This is a key command for this example.

virtual-profiles aaa

!

! Interface BRI 0 is configured for legacy DDR.

interface BRI 0

description Connected to 103

encapsulation ppp

no ip route-cache

dialer rotary-group 0

ppp authentication chap

!

! Interface BRI 1 is configured for dialer profiles.

interface BRI 1

description Connected to 104

encapsulation ppp

! Disable fast switching.

no ip route-cache

dialer pool-member 1

ppp authentication chap

!

! Configure dialer interface 0 for DDR for User1 and User2.

interface dialer 0

ip address 10.1.1.1 255.255.255.0

encapsulation ppp

! Enable legacy DDR.

dialer in-band

! Disable fast switching.

no ip route-cache

dialer map ip 10.1.1.2 name User1 1111

dialer map ip 10.1.1.3 name User2 2222

dialer-group 1

ppp authentication chap

!

! Configure dialer interface 1 for DDR to dial out to User2.

interface dialer 1

ip address 10.2.2.2 255.255.255.0

encapsulation ppp

dialer remote-name User2

dialer string 3333

dialer pool 1

dialer-group 1

! Disable fast switching.

no ip route-cache

ppp authentication chap

dialer-list 1 protocol ip permit

Virtual Profiles Configured by Virtual Templates and AAA Configuration: Example

The following example shows how virtual profiles can be configured by both virtual templates and AAA configuration. User1 and User2 can dial in from anywhere and have their same keepalive settings and their own IP addresses.

The remaining AV pair settings are not used by virtual profiles. They are the network protocol access lists and route filters used by AAA-based per-user configuration.

In the AAA configuration cisco-avpair lines, “\n” is used to indicate the start of a new Cisco IOS command line.

AAA Configuration for User1 and User2

User1 Password = “welcome”

User-Service-Type = Framed-User,

Framed-Protocol = PPP,

cisco-avpair = “lcp:interface-config=keepalive 75\nip address 10.16.100.100 255.255.255.0”,

cisco-avpair = “ip:rte-fltr-out#0=router igrp 60”,

cisco-avpair = “ip:rte-fltr-out#3=deny 172.16.0.0 0.255.255.255”,

cisco-avpair = “ip:rte-fltr-out#4=deny 172.17.0.0 0.255.255.255”,

cisco-avpair = “ip:rte-fltr-out#5=permit any”

User2 Password = “emoclew”

User-Service-Type = Framed-User,

Framed-Protocol = PPP,

cisco-avpair = “lcp:interface-config=keepalive 100\nip address 192.168.200.200 255.255.255.0”,

cisco-avpair = “ip:inacl#3=permit ip any any precedence immediate”,

cisco-avpair = “ip:inacl#4=deny igrp 10.0.1.2 255.255.0.0 any”,

cisco-avpair = “ip:outacl#2=permit ip any any precedence immediate”,

cisco-avpair = “ip:outacl#3=deny igrp 10.0.9.10 255.255.0.0 any”

Router Configuration

! Enable AAA on the router.

aaa new-model

aaa authentication ppp default radius

! This is a key command for this example.

aaa authorization network radius

enable secret 5 $1$koOn$/1QAylov6JFAElxRCrL.o/

enable password lab

!

! Specify use of virtual profiles and a virtual template.

! The following two commands are key for this example.

virtual-profile virtual-template 1

virtual-profile aaa

!

! Define the virtual template.

interface Virtual-Template 1

ip unnumbered ethernet 0

encapsulation ppp

ppp authentication chap

!

! Interface BRI 0 is configured for legacy DDR.

interface BRI 0

description Connected to 103

encapsulation ppp

no ip route-cache

dialer rotary-group 0

ppp authentication chap

!

! Interface BRI 1 is configured for dialer profiles.

interface BRI 1

description Connected to 104

encapsulation ppp

! Disable fast switching.

no ip route-cache

dialer pool-member 1

ppp authentication chap

!

! Configure dialer interface 0 for DDR to dial out to User1 and User2.

interface dialer 0

ip address 10.1.1.1 255.255.255.0

encapsulation ppp

dialer in-band

! Disable fast switching.

no ip route-cache

dialer map ip 10.1.1.2 name User1 1111

dialer map ip 10.1.1.3 name User2 2222

dialer-group 1

ppp authentication chap

!

! Configure dialer interface 0 for DDR to dial out to User2.

interface dialer 1

ip address 10.2.2.2 255.255.255.0

encapsulation ppp

dialer remote-name User2

dialer string 3333

dialer pool 1

dialer-group 1

! Disable fast switching.

no ip route-cache

ppp authentication chap

!

dialer-list 1 protocol ip permit

Virtual Profiles Configured by AAA Plus a VPDN Virtual Template on a VPDN Home Gateway: Example

Like the virtual profiles configured by AAA example earlier in this section, the following example shows the router configuration for virtual profiles by AAA. The user file on the AAA server also includes interface configuration for User1 and User2, the two users. Specifically, User1 and User2 each have their own IP addresses when they are in privileged mode.

In this case, however, the router is also configured as the VPDN home gateway. It clones the VPDN virtual template interface first and then clones the virtual profiles AAA interface configuration. If per-user configuration were configured on this router and the user file on the AAA server had network protocol information for the two users, that information would be applied to the virtual access interface last.

In the AAA configuration cisco-avpair lines, “\n” is used to indicate the start of a new Cisco IOS command line.

AAA Configuration for User1 and User2

User1 Password = "welcome"

User-Service-Type = Framed-User,

Framed-Protocol = PPP,

cisco-avpair = "lcp:interface-config=keepalive 75\nip address 10.100.100.100 255.255.255.0",

User2 Password = "emoclew"

User-Service-Type = Framed-User,

Framed-Protocol = PPP,

cisco-avpair = "lcp:interface-config=keepalive 100\nip address 192.168.200.200 255.255.255.0"

Router Configuration

!Configure the router as the VPDN home gateway.

!

!Enable VPDN and specify the VPDN virtual template to use on incoming calls from the

!network access server.

vpdn enable

vpdn incoming dallas_wan go_blue virtual-template 6

!

!Configure the virtual template interface for VPDN.

interface virtual template 6

ip unnumbered ethernet 0

encapsulation ppp

ppp authentication chap

!

!Enable AAA on the router.

aaa new-model

aaa authentication ppp default radius

aaa authorization network radius

enable secret 5 $1$koOn$/1QAylov6JFAElxRCrL.o/

enable password lab

!

!Specify configuration of virtual profiles by aaa.

virtual-profiles aaa

!

!Configure the physical synchronous serial 0 interface.

interface Serial 0

description Connected to 101

encapsulation ppp

!Disable fast switching.

no ip route-cache

ppp authentication chap

!

!Configure serial interface 1 for DDR. S1 uses dialer rotary group 0, which is

!defined on BRI interface 0.

interface serial 1

description Connected to 102

encapsulation ppp

dialer in-band

! Disable fast switching.

no ip route-cache

dialer rotary-group 0

ppp authentication chap

!

interface BRI 0

description Connected to 103

encapsulation ppp

no ip route-cache

dialer rotary-group 0

ppp authentication chap

!

interface BRI 1

description Connected to 104

encapsulation ppp

!Disable fast switching.

no ip route-cache

dialer pool-member 1

ppp authentication chap

!

!Configure dialer interface 0 for DDR to call and receive calls from User1 and User2.

interface dialer 0

ip address 10.1.1.1 255.255.255.0

encapsulation ppp

!Enable legacy DDR.

dialer in-band

!Disable fast switching.

no ip route-cache

dialer map ip 10.1.1.2 name User1 1111

dialer map ip 10.1.1.3 name User2 2222

dialer-group 1

ppp authentication chap

!

!Configure dialer interface 1 for DDR to dial out to User2.

interface dialer 1

ip address 10.2.2.2 255.255.255.0

encapsulation ppp

dialer remote-name User2

dialer string 3333

dialer pool 1

dialer-group 1

!Disable fast switching.

no ip route-cache

ppp authentication chap

dialer-list 1 protocol ip permit

Additional References

The following sections provide references related to configuring virtual profiles.

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

Dial commands

Cisco IOS Dial Command Reference

Standards

Standard

Title

None

—

MIBs

MIB

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

RFCs

RFC

Title

None

—

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for Configuring Virtual Profiles

Table 2 lists the features in this module and provides links to specific configuration information.

Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Note Table 2 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.

Table 2 Feature Information for Configuring Virtual Profiles

Feature Name

Releases

Feature Information

Configuring Virtual Profiles

11.3

A virtual profile is a unique application that can create and configure a virtual access interface dynamically when a dial-in call is received and that can tear down the interface dynamically when the call ends.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 1997–2010 Cisco Systems, Inc. All rights reserved.

Virtual Interface Template Service

First Published: May 10, 2001

Last Updated: November 20, 2014

The Virtual Interface Template Service feature provides a generic service that can be used to apply predefined interface configurations (virtual interface template services) in creating and freeing virtual access interfaces dynamically, as needed.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the “Feature Information for Virtual Interface Template” section.

Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Contents

- Restrictions for Virtual Interface Template Service

- Information About Virtual Interface Template Service

- How to Configure a Virtual Interface Template

- Configuration Examples for Virtual Interface Template

- Feature Information for Virtual Interface Template

Restrictions for Virtual Interface Template Service

The following restrictions apply for configuring the virtual interface template service feature:

- Although a system can generally support many virtual interface template services, one template for each virtual access application is a more realistic limit.

- When in use, each virtual access interface cloned from a template requires the same amount of memory as a serial interface. Limits to the number of virtual access interfaces that can be configured are determined by the platform.

- You cannot reuse virtual interface templates. You need to create different templates for different interface configurations.

- You cannot directly configure virtual access interfaces. You need to configure a virtual access interface by configuring a virtual interface template service or including the configuration information of the user on an authentication, authorization, and accounting (AAA) server. However, information about an in-use virtual access interface can be displayed, and the virtual access interface can be cleared.

- Virtual interface templates provide no direct value to you; they must be applied to or associated with a virtual access feature using a command with the virtual-template keyword.

For example, the interface virtual-template command creates the virtual interface template service.

For a complete description of the virtual interface service commands mentioned in this chapter, refer to the Cisco IOS Dial Technologies Command Reference. For information about all Cisco IOS commands, use the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or a Cisco IOS master commands list.

Information About Virtual Interface Template Service

To configure the virtual interface template service, you should understand the following concepts:

- Virtual Interface Template Service Overview

- Benefits of Virtual Interface Template Service

- Features that Use Virtual Interface Template Service

- Selective Virtual Access Interface Creation

Virtual Interface Template Service Overview

Virtual interface template services can be configured independently of any physical interface and applied dynamically, as needed, to create virtual access interfaces. When a user dials in, a predefined configuration template is used to configure a virtual access interface; when the user is done, the virtual access interface goes down and the resources are freed for other dial-in uses.

A virtual interface template service is a logical entity—a configuration for a serial interface but not tied to a physical interface—that can be applied dynamically as needed. Virtual access interfaces are virtual interfaces that are created, configured dynamically (for example, by cloning a virtual interface template service), used, and then freed when no longer needed.

Virtual interface template services are one possible source of configuration information for a virtual access interface.

Each virtual access interface can clone from only one template. But some applications can take configuration information from multiple sources; The result of using template and AAA configuration sources is a virtual access interface uniquely configured for a specific dial-in user.

Figure 1 illustrates that a device can create a virtual access interface by first using the information from a virtual interface template service (if any is defined for the application) and then using the information in a per-user configuration.

Figure 1 Possible Configuration Sources for Virtual Access Interfaces

Benefits of Virtual Interface Template Service

The virtual interface template service is intended primarily for customers with large numbers of dial-in users and provides the following benefits:

- Easy maintenance: It allows customized configurations to be predefined and then applied dynamically when the specific need arises.

- Scalability: It allows interface configuration to be separated from physical interfaces. Virtual interfaces can share characteristics, no matter what specific type of interface the user called on.

- Consistency and configuration ease: It allows the same predefined template to be used for all users dialing in for a specific application.

- Efficient device operation: It frees the virtual access interface memory for another dial-in use when the call from the user ends.

Features that Use Virtual Interface Template Service

The following features use virtual interface template service to create virtual access interfaces dynamically:

- Virtual Private Dialup Networks (VPDNs)

- Virtual interface templates for protocol translation

- PPP over ATM

Virtual interface templates are supported on all platforms that support these features.

To create and configure a virtual interface template interface, compete the tasks in the “Creating and Configuring a Virtual Interface Template” section. To apply a virtual interface template service, refer to the specific feature that applies the virtual interface template.

All prerequisites depend on the feature that is applying a virtual interface template to create a virtual access interface. Virtual interface template services themselves have no other prerequisites.

Selective Virtual Access Interface Creation

You can configure a device to automatically determine whether to create a virtual access interface for each inbound connection. In particular, a call that is received on a physical asynchronous interface that uses a AAA per-user configuration for RADIUS or TACACS+ can be processed without a virtual access interface being created by a device.

To determine whether a virtual access interface is created, ensure the following exists:

- AAA per-user configuration

- Support for link interface support direct per-user AAA

A virtual access interface is created if there is a AAA per-user configuration and the link interface does not support direct per-user AAA (such as ISDN).

A virtual access interface is not created if the following conditions are not satisfied:

- There is no AAA per-user configuration.

- There is AAA per-user configuration and the link interface does support direct per-user AAA (such as asynchronous).

How to Configure a Virtual Interface Template

This section contains the following tasks:

- Creating and Configuring a Virtual Interface Template (required)

- Monitoring and Maintaining a Virtual Access Interface (required)

Note The order in which you create virtual interface template service and configure the features that use the templates and profiles is not important. They must exist, however, before someone calling in can use them.

Creating and Configuring a Virtual Interface Template

To create and configure a virtual interface template service, use the interface virtual-template command.

Note Configuring the ip address command within a virtual interface template service is not recommended. Configuring a specific IP address in a virtual interface template can result in the establishment of erroneous routes and the loss of IP packets.

Other PPP configuration commands can be added to the virtual interface template configuration. For example, you can add the ppp authentication chap command.

All configuration commands that apply to serial interfaces can also be applied to virtual interface template interfaces, except the shutdown and dialer commands.

For virtual interface template examples, see the “Configuration Examples for Virtual Interface Template” section section.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface virtual-template number

4. ip unnumbered ethernet number

5. encapsulation ppp

6. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface virtual-template number

Device(config)# interface virtual-template 0/0

Creates a virtual interface template and enters interface configuration mode.

Step 4

ip unnumbered ethernet number

Device(config-if)# ip unnumbered ethernet 0/0

Enables IP without assigning a specific IP address on the LAN.

Step 5

encapsulation ppp

Device(config-if)# encapsulation ppp

Enables PPP encapsulation on the virtual interface template.

Step 6

end

Device(config-if)# end

Exits interface configuration mode and returns to privileged EXEC mode.

Monitoring and Maintaining a Virtual Access Interface

When a virtual interface template or a configuration from a user on a AAA server or both are applied dynamically, a virtual access interface is created. Although a virtual access interface cannot be created and configured directly, it can be displayed and cleared.

To display or clear a specific virtual access interface, use the show interfaces virtual-access and clear interface virtual-access commands.

SUMMARY STEPS

1. enable

2. show interfaces virtual-access number

3. clear interface virtual-access number

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

show interfaces virtual-access number

Device# show interfaces virtual-access 3

Displays the configuration of the virtual access interface.

Step 3

clear interface virtual-access number

Device# clear interface virtual-access 3

Tears down the virtual access interface and frees the memory for other dial-in uses.

Configuration Examples for Virtual Interface Template

The following sections provide virtual interface template configuration examples:

- Virtual Interface Template: Example

- Selective Virtual Access Interface: Example

- Selective Virtual Access Interface Configuration for RADIUS per User: Example

- Selective Virtual Access Interface Configuration for TACACS+ per User: Example

Virtual Interface Template: Example

The following example shows how to verify a virtual interface template configuration.

Note Effective with Cisco Release 12.4(11)T, the l2f protocol command was removed in Cisco IOS software.

Device# show interfaces virtual-access 1

Virtual-Access1 is a L2F link interface

interface Virtual-Access1 configuration...

ip unnumbered ethernet0

ipx ppp-client Loopback2

no cdp enable

ppp authentication chap

Selective Virtual Access Interface: Example

The following example shows how to create a virtual access interface for incoming calls that require a virtual access interface:

aaa new-model

aaa authentication ppp default local radius tacacs

aaa authorization network default local radius tacacs

virtual-profile if-needed

virtual-profile virtual-template 1

virtual-profile aaa

!

interface virtual-template 1

ip unnumbered Ethernet 0

no ip directed-broadcast

no keepalive

ppp authentication chap

ppp multilink

Selective Virtual Access Interface Configuration for RADIUS per User: Example

This example shows how to create AAA per-user configuration for a RADIUS user profile. When a AAA per-user configuration for a RADIUS user profile exists, a virtual access interface is configured automatically.

RADIUS user profile:

name1 Password = "test"

User-Service-Type = Framed-User,

Framed-Protocol = PPP,

cisco-avpair = "ip:inacl#1=deny 10.10.10.10 0.0.0.0",

cisco-avpair = "ip:inacl#1=permit any"

Selective Virtual Access Interface Configuration for TACACS+ per User: Example

This example shows how to create AAA per-user configuration for a TACACS+ user profile:

user = name1 {

name = "name1"

global = cleartext test

service = PPP protocol= ip {

inacl#1="deny 10.10.10.10 0.0.0.0"

inacl#1="permit any"

}

}

Additional References

The following sections provide references related to the Virtual Interface Template Service feature.

Related Documents

Related Topic

Document Title

Dial interfaces, controllers and lines

“Overview of Dial Interfaces, Controllers, and Lines” module in the Cisco IOS Dial Technologies Configuration Guide

Dial commands

Cisco IOS Dial Technologies Command Reference

Standards

Standard

Title

None

—

MIBs

MIB

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

RFCs

RFC

Title

None

—

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/techsupport

Feature Information for Virtual Interface Template

Table 1 lists the release history for this feature.

Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Note Table 1 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.

Table 1 Feature Information for Virtual Interface Templates

Feature Name

Releases

Feature Information

Virtual Interface Template Service

11.2(1)

12.2(14)S

12.2(27)SBA

12.2(33)SRE

Cisco IOS XE 3S

Virtual interface template service can be configured independently of any physical interface and applied dynamically to create virtual access interfaces.

The following sections provide information about this feature:

- Information About Virtual Interface Template Service

- Creating and Configuring a Virtual Interface Template

- Monitoring and Maintaining a Virtual Access Interface

The following commands were introduced or modified: clear interfaces virtual-access, interface virtual-template, and show interfaces virtual-access

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2001–2009 Cisco Systems, Inc. All rights reserved.

Configuring Media-Independent PPP and Multilink PPP

First Published: May 10, 2001

Last Updated: November 20, 2014

The Configuring Media-Independent PPP and Multilink PPP module describes how to configure PPP and Multilink PPP (MLP) features on any interface. This module also describes address pooling for point-to-point links, which is available on all asynchronous serial, synchronous serial, and ISDN interfaces.

Multilink PPP provides a method for spreading traffic across multiple physical WAN links.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the “Feature Information for Configuring Media-Independent PPP and Multilink PPP” section.

Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Contents

- Information About Media-Independent PPP and Multilink PPP

- How to Configure Media-Independent PPP and Multilink PPP

- Configuration Examples for PPP and MLP

- Additional References

- Feature Information for Configuring Media-Independent PPP and Multilink PPP

Prerequisites for Media-Independent PPP and Multilink PPP

Understanding PPP and multilink operations.

Information About Media-Independent PPP and Multilink PPP

To configure the Media-Independent PPP and Multilink PPP, you should understand the following concepts:

- Point-to-Point Protocol

- CHAP or PPP Authentication

- Microsoft Point-to-Point Compression

- IP Address Pooling

Point-to-Point Protocol

Point-to-Point Protocol (PPP), described in RFC 1661, encapsulates network layer protocol information over point-to-point links. You can configure PPP on the following types of physical interfaces:

- Asynchronous serial

- High-Speed Serial Interface (HSSI)

- ISDN

- Synchronous serial

The implementation of PPP supports authentication using Challenge Handshake Authentication Protocol (CHAP), Microsoft Challenge Handshake Authentication Protocol (MS-CHAP), or Password Authentication Protocol (PAP), and the option 4, and option 5, and Magic Number configuration options.

Magic Number support is available on all serial interfaces. PPP always attempts to negotiate for Magic Numbers, which are used to detect looped-back lines. Depending on how the down-when-looped command is configured, the router might shut down a link if it detects a loop.

CHAP or PPP Authentication

PPP with CHAP or PAP authentication is often used to inform the central site about which remote routers are connected to it.

With this authentication information, if the router or access server receives another packet for a destination to which it is already connected, it does not place an additional call. However, if the router or access server is using rotaries, it sends the packet out the correct port.

CHAP and PAP were originally specified in RFC 1334, and CHAP was updated in RFC 1994. These protocols are supported on synchronous and asynchronous serial interfaces. When using CHAP or PAP authentication, each router or access server identifies itself by a name. This identification process prevents a router from placing another call to a router to which it is already connected, and also prevents unauthorized access.

Access control using CHAP or PAP is available on all serial interfaces that use PPP encapsulation. The authentication feature reduces the risk of security violations on your router or access server. You can configure either CHAP or PAP for the interface.

Note To use CHAP or PAP, you must be running PPP encapsulation.

When CHAP is enabled on an interface and a remote device attempts to connect to it, the local router or access server sends a CHAP packet to the remote device. The CHAP packet requests or “challenges” the remote device to respond. The challenge packet consists of an ID, a random number, and the hostname of the local router.

The required response has two parts:

- An encrypted version of the ID, a secret password, and the random number

- Either the hostname of the remote device or the name of the user on the remote device

When the local router or access server receives the response, it verifies the secret password by performing the same encryption operation as indicated in the response and looking up the required hostname or username. The secret passwords must be identical on the remote device and the local router.

Because this response is sent, the password is never sent in clear text, preventing other devices from stealing it and gaining illegal access to the system. Without the proper response, the remote device cannot connect to the local router.

CHAP transactions occur only when a link is established. The local router or access server does not request a password during the rest of the call. (The local device can, however, respond to such requests from other devices during a call.)

When PAP is enabled, the remote router attempting to connect to the local router or access server is required to send an authentication request. The username and password specified in the authentication request are accepted, and the Cisco IOS software sends an authentication acknowledgment.

After you have enabled CHAP or PAP, the local router or access server requires authentication from remote devices. If the remote device does not support the enabled protocol, no traffic will be passed to that device.

To use CHAP or PAP:

- Enable PPP encapsulation.

- Enable CHAP or PAP on the interface.

For CHAP, configure hostname authentication and the secret password for each remote system with which authentication is required.

Microsoft Point-to-Point Compression

Microsoft Point-to-Point Compression (MPPC) is a scheme used to compress PPP packets between Cisco and Microsoft client devices. The MPPC algorithm is designed to optimize bandwidth utilization in order to support multiple simultaneous connections. The MPPC algorithm uses a Lempel-Ziv (LZ)-based algorithm with a continuous history buffer called a dictionary.

The Compression Control Protocol (CCP) configuration option for MPPC is 18.

Exactly one MPPC datagram is encapsulated in the PPP information field. The PPP protocol field indicates the hexadecimal type of 00FD for all compressed datagrams. The maximum length of the MPPC datagram sent over PPP is the same as the MTU of the PPP interface; however, this length cannot be greater than 8192 bytes because the history buffer is limited to 8192 bytes. If compressing the data results in data expansion, the original data is sent as an uncompressed MPPC packet.

The history buffers between compressor and decompressor are synchronized by maintaining a 12-bit coherency count. If the decompressor detects that the coherency count is out of sequence, the following error recovery process is performed:

1. The Reset Request (RR) packet is sent from the decompressor.

2. The compressor then flushes the history buffer and sets the flushed bit in the next packet it sends.

3. Upon receiving the flushed bit set packet, the decompressor flushes the history buffer.

Synchronization is achieved without CCP using the Reset Acknowledge (RA) packet, which can consume additional time.

Compression negotiation between a router and a Windows 95 client occurs through the following process:

1. Windows 95 sends a request for both STAC (option 17) and MPPC (option 18) compression.

2. The router sends a negative acknowledgment (NAK) requesting only MPPC.

3. Windows 95 resends the request for MPPC.

The router sends an acknowledgment (ACK) confirming MPPC compression negotiation.

IP Address Pooling

A point-to-point interface must be able to provide a remote node with its IP address through the IP Control Protocol (IPCP) address negotiation process. The IP address can be obtained from a variety of sources. The address can be configured through the command line, entered with an EXEC-level command, provided by TACACS+ or the Dynamic Host Configuration Protocol (DHCP), or from a locally administered pool.

IP address pooling uses a pool of IP addresses from which an incoming interface can provide an IP address to a remote node through IPCP address negotiation process. IP address pooling also enhances configuration flexibility by allowing multiple types of pooling to be active simultaneously.

The IP address pooling feature allows configuration of a global default address pooling mechanism, per-interface configuration of the address pooling mechanism, and per-interface configuration of a specific address or pool name.

Peer Address Allocation

A peer IP address can be allocated to an interface through several methods:

- Dialer map lookup—This method is used only if the peer requests an IP address, no other peer IP address has been assigned, and the interface is a member of a dialer group.

- PPP or Serial Line Internet Protocol (SLIP) EXEC command—An asynchronous dialup user can enter a peer IP address or hostname when PPP or SLIP is invoked from the command line. The address is used for the current session and then discarded.

- IPCP negotiation—If the peer presents a peer IP address during IPCP address negotiation and no other peer address is assigned, the presented address is acknowledged and used in the current session.

- Default IP address.

- TACACS+ assigned IP address—During the authorization phase of IPCP address negotiation, TACACS+ can return an IP address that the user being authenticated on a dialup interface can use. This address overrides any default IP address and prevents pooling from taking place.

- DHCP retrieved IP address—If configured, the routers acts as a proxy client for the dialup user and retrieves an IP address from a DHCP server. That address is returned to the DHCP server when the timer expires or when the interface goes down.

- Local address pool—The local address pool contains a set of contiguous IP addresses (a maximum of 1024 addresses) stored in two queues. The free queue contains addresses available to be assigned and the used queue contains addresses that are in use. Addresses are stored to the free queue in first-in, first-out (FIFO) order to minimize the chance the address will be reused, and to allow a peer to reconnect using the same address that it used in the last connection. If the address is available, it is assigned; if not, another address from the free queue is assigned.

- Chat script (asynchronous serial interfaces only)—The IP address in the dialer map command entry that started the script is assigned to the interface and overrides any previously assigned peer IP address.

- Virtual terminal/protocol translation—The translate command can define the peer IP address for a virtual terminal (pseudo asynchronous interface).

- The pool configured for the interface is used, unless TACACS+ returns a pool name as part of authentication, authorization, and accounting (AAA). If no pool is associated with a given interface, the global pool named default is used.

Precedence Rules

The following precedence rules of peer IP address support determine which address is used. Precedence is listed from most likely to least likely:

1. AAA/TACACS+ provided address or addresses from the pool named by AAA/TACACS+

2. An address from a local IP address pool or DHCP (typically not allocated unless no other address exists)

3. Dialer map lookup address (not done unless no other address exists)

4. Address from an EXEC-level PPP or SLIP command, or from a chat script

5. Configured address from the peer default ip address command or address from the protocol translate command

6. Peer-provided address from IPCP negotiation (not accepted unless no other address exists)

MLP on Synchronous Serial Interfaces

Address pooling is available on all asynchronous serial, synchronous serial, ISDN BRI, and ISDN PRI interfaces that are running PPP and PPPoX sessions.

MLP provides characteristics are most similar to hardware inverse multiplexers, with good manageability and Layer 3 services support. Figure 1 shows a typical inverse multiplexing application using two Cisco routers and Multilink PPP over four T1 lines.

Figure 1 Inverse Multiplexing Application Using Multilink PPP

How to Configure Media-Independent PPP and Multilink PPP

This section includes the following procedures:

- Configuring PPP and MLP

- Configuring MLP Interleaving and Queueing

- Monitoring and Maintaining PPP and MLP Interfaces

Configuring PPP and MLP

Perform the following task in interface configuration mode to configure PPP on a serial interface (including ISDN). This task is required for PPP encapsulation.

- Enabling PPP Encapsulation

You can also complete the tasks in the following sections; these tasks are optional but offer a variety of uses and enhancements for PPP on your systems and networks:

- Enabling CHAP or PAP Authentication

- Configuring Compression of PPP Data

- Configuring IP Address Pooling

- Disabling or Reenabling Peer Neighbor Routes

- Configuring Multilink PPP

- Configuring Multilink PPP

- Configuring MLP Interleaving

- Creating a Multilink Bundle

- Assigning an Interface to a Multilink Bundle

- Disabling PPP Multilink Fragmentation

See the “Monitoring and Maintaining PPP and MLP Interfaces” section for tips on maintaining PPP. See the “Configuration Examples for PPP and MLP” section to understand how to implement PPP and MLP in your network.

Enabling PPP Encapsulation

The encapsulation ppp command enables PPP on serial lines to encapsulate IP and other network protocol datagrams.

SUMMARY STEPS

1. enable

2. configure terminal

3. configure fastethernet number

4. encapsulation ppp

5. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface fastethernet number

Device(config)# interface fastethernet 0/0

Enters interface configuration mode.

Step 4

encapsulation ppp

Device(config-if) # encapsulation ppp

Enables PPP encapsulation.
to disable echo requests.

Step 5

end

Device(config-if)# end

Exits interface configuration mode.

Enabling CHAP or PAP Authentication

To enable CHAP or PAP authentication, perform the steps mentioned in this section.

Caution If you use a list name that has not been configured with the aaa authentication ppp command, you disable PPP on the line.

For an example of CHAP, see the section ““Examples: CHAP with an Encrypted Password:” section”. CHAP is specified in RFC 1994, PPP Challenge Handshake Authentication Protocol (CHAP).

For information about MS-CHAP, see MS-CHAP Support.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface fastethernet number

4. ppp authentication {chap | chap pap | pap chap | pap} [if-needed] [list-name | default] [callin]

5. ppp use-tacacs [single-line]

or

aaa authentication ppp

6. exit

7. username name [user-maxlinks link-number] password secret

8. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface fastethernet number

Device(config)# interface fastethernet 0/0

Enters Interface Configuration mode.

Step 4

ppp authentication {chap | chap pap | pap chap | pap} [if-needed] [list-name | default] [callin]

Device(config-if)# ppp authentication chap

Defines the authentication methods supported and the order in which they are used.
command only with TACACS or extended TACACS. command with AAA/TACACS+.

Step 5

ppp use-tacacs [single-line]

or

aaa authentication ppp

Device(config-if)# ppp use-tacacs single-line

or

Device(config-if)# aaa authentication ppp

Configure TACACS on a specific interface as an alternative to global host authentication.

Step 6

exit

Device(config-if)# exit

Exits interface configuration mode.

Step 7

username name [user-maxlinks link-number] password secret

Device(config)# username name user-maxlinks 1 password password1

Configures identification.

- Optionally, you can specify the maximum number of connections a user can establish.

- To use the user-maxlinks keyword, you must also use the aaa authorization network default local command and PPP encapsulation and name authentication on all the interfaces the user will be accessing.

Step 8

end

Device(config)# end

Exits global configuration mode and enters privileged EXEC mode.

Configuring Compression of PPP Data

You can configure point-to-point software compression on serial interfaces that use PPP encapsulation. Compression reduces the size of a PPP frame via lossless data compression. PPP encapsulations support both predictor and Stacker compression algorithms.

If most of your traffic is already compressed files, do not use compression.

To configure compression of PPP data, perform the steps in this section.

Software Compression

Software compression is available on all router platforms. Software compression is performed by the main processor in the router.

Compression is performed in software and might significantly affect system performance. We recommend that you disable compression if the router CPU load exceeds 65 percent. To display the CPU load, use the show process cpu EXEC command.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface fastethernet number

4. encapsulation PPP

5. compress [predictor | stac | mppc [ignore-pfc]]

6. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface fastethernet number

Device(config)# interface fastethernet 0/0

Enters interface configuration mode.

Step 4

encapsulation ppp

Device(config-if)# encapsulation ppp

Enables encapsulation of a single protocol on the serial line.

Step 5

compress [predictor | stac | mppc [ignore-pfc]]

Device(config-if)# compress predictor

Enables compression.

Step 6

end

Device(config-if)# end

Exits interface configuration mode.

Configuring Microsoft Point-to-Point Compression

Perform this task to configure MPCC. This will help you set MPPC once PPP encapsulation is configured on the router.

Prerequisites

Ensure that PPP encapsulation is enabled before you configure MPPC. For information on how to configure PPP encapsulation, see the “Enabling PPP Encapsulation” section”.

Restrictions

The following restrictions apply to the MPPC feature:

- MPPC is supported only with PPP encapsulation.

- Compression can be processor intensive because it requires a reserved block of memory to maintain the history buffer. Do not enable modem or hardware compression because it may cause performance degradation, compression failure, or data expansion.

- Both ends of the point-to-point link must be using the same compression method (STAC, Predictor, or MPPC, for example).

SUMMARY STEPS

1. enable

2. configure terminal

3. interface serial number

4. compress [mppc [ignore-pfc]]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface serial number

Device(config)# interface serial 2/0

Enters interface configuration mode.

Step 4

compress [mppc [ignore-pfc]]

Device(config-if)# compress mppc

Enables encapsulation of a single protocol on the serial line.

- The ignore-pfc keyword instructs the router to ignore the protocol field compression flag negotiated by Link Control Protocol (LCP). For example, the uncompressed standard protocol field value for IP is 0x0021 and 0x21 when compression is enabled. When the ignore-pfc option is enabled, the router will continue to use the uncompressed value (0x0021). Using the ignore-pfc option is helpful for some asynchronous driver devices that use an uncompressed protocol field (0x0021), even though the protocol field compression is negotiated between peers.

Examples

Following is sample debug ppp negotiation command output showing protocol reject:

PPP Async2: protocol reject received for protocol = 0x2145

PPP Async2: protocol reject received for protocol = 0x2145

PPP Async2: protocol reject received for protocol = 0x2145

Configuring IP Address Pooling

You can define the type of IP address pooling mechanism used on router interfaces in one or both of the ways described in the following sections:

- Defining the Global Default Address Pooling Mechanism

- Configuring IP Address Assignment

Defining the Global Default Address Pooling Mechanism

The global default mechanism applies to all point-to-point interfaces that support PPP encapsulation and that have not otherwise been configured for IP address pooling. You can define the global default mechanism to be either DHCP or local address pooling.

To configure the global default mechanism for IP address pooling, perform the tasks in the following sections:

- Defining DHCP as the Global Default Mechanism

- Defining Local Address Pooling as the Global Default Mechanism

After you have defined a global default mechanism, you can disable it on a specific interface by configuring the interface for some other pooling mechanism. You can define a local pool other than the default pool for the interface or you can configure the interface with a specific IP address to be used for dial-in peers.

You can also control the DHCP network discovery mechanism; see the following section for more information:

- Controlling DHCP Network Discovery

Defining DHCP as the Global Default Mechanism

DHCP specifies the following components:

- A DHCP server—A host-based DHCP server configured to accept and process requests for temporary IP addresses.

- A DHCP proxy client—A Cisco access server configured to arbitrate DHCP calls between the DHCP server and the DHCP client. The DHCP client-proxy feature manages a pool of IP addresses available to dial-in clients without a known IP address.

Perform this task to enable DHCP as the global default mechanism.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip address-pool dhcp-proxy-client

4. ip dhcp-server [ip-address | name]

5. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

ip address-pool dhcp-proxy-client

Device(config)# ip address-pool dhcp-proxy-client

Specifies the DHCP client-proxy feature as the global default mechanism.

- The peer default ip address command and the member peer default ip address command can be used to define default peer IP addresses.

Note You can provide as few as one or as many as ten DHCP servers for the proxy client (the Cisco router or access server) to use. The DHCP servers provide temporary IP addresses.

Step 4

ip dhcp-server [ip-address | name]

Device(config)# ip dhcp-server 209.165.201.1

(Optional) Specifies the IP address of a DHCP server for the proxy client to use.

Step 5

end

Device(config)# end

Exits global configuration mode.

Defining Local Address Pooling as the Global Default Mechanism

Perform this task to define local address pooling as the global default mechanism.

Note If no other pool is defined, a local pool called “default” is used. Optionally, you can associate an address pool with a named pool group.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip address-pool local

4. ip local pool {named-address-pool | default} first-IP-address [last-IP-address] [group group-name] [cache-size size]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

ip address-pool local

Device(config)# ip address-pool local

Specifies local address pooling as the global default mechanism.

Step 4

ip local pool {named-address-pool | default} first-IP-address [last-IP-address] [group group-name] [cache-size size]

Device(config)# ip local pool default 192.0.2.1

Creates one or more local IP address pools.

Controlling DHCP Network Discovery

Perform the steps in this section to allow peer routers to dynamically discover Domain Name System (DNS) and NetBIOS name server information configured on a DHCP server using PPP IPCP extensions.

The ip dhcp-client network-discovery global configuration command provides a way to control the DHCP network discovery mechanism. The number of DHCP Inform or Discovery messages can be set to 1 or 2, which determines how many times the system sends the DHCP Inform or Discover messages before stopping network discovery. You can set a timeout period from 3 to 15 seconds, or leave the default timeout period at 15 seconds. The default for the informs and discovers keywords is 0, which disables the transmission of these messages.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip dhcp-client network-discovery informs number-of-messages discovers number-of-messages period seconds

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

ip dhcp-client network-discovery informs number-of-messages discovers number-of-messages period seconds

Device(config)# ip dhcp-client network-discovery informs 2 discovers 2 period 2

Provides control of the DHCP network discovery mechanism by allowing the number of DHCP Inform and Discover messages to be sent, and a timeout period for retransmission, to be configured.

Configuring IP Address Assignment

Perform this task to configure IP address allignment.

After you have defined a global default mechanism for assigning IP addresses to dial-in peers, you can configure the few interfaces for which it is important to have a nondefault configuration. You can do any of the following;

- Define a nondefault address pool for use by a specific interface.

- Define DHCP on an interface even if you have defined local pooling as the global default mechanism.

- Specify one IP address to be assigned to all dial-in peers on an interface.

- Make temporary IP addresses available on a per-interface basis to asynchronous clients using SLIP or PPP.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip local pool {named-address-pool | default} {first-IP-address [last-IP-address]} [group group-name] [cache-size size]}

4. interface type number

5. peer default ip address pool pool-name-list

6. peer default ip address pool dhcp

7. peer default ip address ip-address

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

ip local pool {named-address-pool | default} {first-IP-address [last-IP-address]} [group group-name] [cache-size size]}

Device(config)# ip local pool default 192.0.2.0

Creates one or more local IP address pools.

Step 4

interface type number

Device(config)# interface ethernet 2/0

Specifies the interface and enters interface configuration mode.

Step 5

peer default ip address pool pool-name-list

Device(config-if)# peer default ip address pool 2

Specifies the pool or pools for the interface to use.

Step 6

peer default ip address pool dhcp

Device(config-if)# peer default ip address pool dhcp

Specifies DHCP as the IP address mechanism on this interface.

Step 7

peer default ip address ip-address

Device(config-if)# peer default ip address 192.0.2.2

Specifies the IP address to assign to all dial-in peers on an interface.

Troubleshooting PPP

You can troubleshoot PPP reliable link by using the debug lapb command and the debug ppp negotiations, debug ppp errors, and debug ppp packets commands. You can determine whether Link Access Procedure, Balanced (LAPB) has been established on a connection by using the show interface command.

Disabling or Reenabling Peer Neighbor Routes

The Cisco IOS software automatically creates neighbor routes by default; that is, it automatically sets up a route to the peer address on a point-to-point interface when the PPP IPCP negotiation is completed.

To disable this default behavior or to reenable it once it has been disabled, perform the following task:

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type number

4. no peer neighbor-route

5. peer neighbor-route

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Device(config)# interface ethernet 0/1

Specifies the interface and enters interface configuration mode.

Step 4

no peer neighbor-route

Device(config-if)# no peer neighbor-route

Disables creation of neighbor routes.

Step 5

peer neighbor-route

Device(config-if)# peer neighbor-route

Reenables creation of neighbor routes.

Note If entered on a dialer or asynchronous group interface, this command affects all member interfaces.

Configuring Multilink PPP

The Multilink PPP feature provides load balancing functionality over multiple WAN links, while providing multivendor interoperability, packet fragmentation and proper sequencing, and load calculation on both inbound and outbound traffic. The Cisco implementation of MLP supports the fragmentation and packet sequencing specifications in RFC 1990. Additionally, you can change the default endpoint discriminator value that is supplied as part of user authentication. Refer to RFC 1990 for more information about the endpoint discriminator.

MLP allows packets to be fragmented and the fragments to be sent at the same time over multiple point-to-point links to the same remote address. The multiple links come up in response to a defined dialer load threshold. The load can be calculated on inbound traffic, outbound traffic, or on either, as needed for the traffic between the specific sites. MLP provides bandwidth on demand and reduces transmission latency across WAN links.

MLP is designed to work over synchronous and asynchronous serial and BRI and PRI types of single or multiple interfaces that have been configured to support both dial-on-demand rotary groups and PPP encapsulation.

Perform the tasks in the following sections, as required for your network, to configure MLP:

- Configuring MLP on Synchronous Interfaces

- Configuring MLP on Asynchronous Interfaces

- Configuring MLP on a Single ISDN BRI Interface

- Configuring MLP on Multiple ISDN BRI Interfaces

- Configuring MLP Using Multilink Group Interfaces

- Changing the Default Endpoint Discriminator

Configuring MLP on Synchronous Interfaces

To configure Multilink PPP on synchronous interfaces, you configure the synchronous interfaces to support PPP encapsulation and Multilink PPP.

Perform this task to configure a synchronous interface.

SUMMARY STEPS

1. enable

2. configuration terminal

3. interface serial 1

4. no ip address

5. encapuslation ppp

6. ppp multilink

7. pulse-time seconds

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface serial number

Device(config)# interface serial 1

Specifies an asynchronous interface and enters interface configuration mode.

Step 4

no ip address

Device(config-if)# no ip address

Specifies no IP address for the interface.

Step 5

encapsulation ppp

Device(config-if)# encapsulation ppp

Enables PPP encapsulation.

Step 6

ppp multilink

Device(config-if)# ppp multilink

Enables Multilink PPP.

Step 7

pulse-time seconds

Device(config-if)# pulse-time 60

Enables pulsing data terminal ready (DTR) signal intervals on an interface.

Note Repeat these steps for additional synchronous interfaces, as needed.

Configuring MLP on Asynchronous Interfaces

Perform the following steps in this section to configure an asynchronous interface to support DDR and PPP encapsulation and then configure a dialer interface to support PPP encapsulation, bandwidth on demand, and Multilink PPP.

At some point, adding more asynchronous interfaces does not improve performance, With the default maximum transmission unit (MTU) size, MLP should support three asynchronous interfaces using V.34 modems. However, packets might be dropped occasionally if the maximum transmission unit (MTU) size is small or large bursts of short frames occur.

Note To configure a dialer interface to support PPP encapsulation and Multilink PPP, use the dialer load-threshold command.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface async number

4. no ip address

5. dialer in-band

6. dialer rotary-group number

7. dialer load-threshold load [inbound | outbound | either]

8. ppp multilink

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface async number

Device(config)# interface async 0/0

Specifies an asynchronous interface and enters interface configuration mode.

Step 4

no ip address

Device(config-if)# no ip address

Specifies no IP address for the interface.

Step 5

Device(config-if)# encapsulation ppp

Device# configure terminal

Enables PPP encapsulation.

Step 6

dialer in-band

Device(config-if)# encapsulation ppp

Enables DDR on the interface.

Step 7

dialer rotary-group number

Device(config-if)# dialer rotary-group 1

Includes the interface in a specific dialer rotary group.

Step 8

dialer load-threshold load [inbound | outbound | either]

Device(config-if)# dialer load-threshold 100

Configures bandwidth on demand by specifying the maximum load before the dialer places another call to a destination.

Step 9

ppp multilink

Device(config-if)# ppp multilink

Enables Multilink PPP.

Configuring MLP on a Single ISDN BRI Interface

To enable MLP on a single ISDN BRI interface, you are not required to define a dialer rotary group separately because ISDN interfaces are dialer rotary groups by default.

Perform this task to enable PPP on an ISDN BRI interface.

If you do not use PPP authentication procedures (Step 8), your telephone service must pass caller ID information.

The load threshold number is required. For an example of configuring MLP on a single ISDN BRI interface, see the “Example: MLP on One ISDN BRI Interface” section.

Note When MLP is configured and you want a multilink bundle to be connected indefinitely, use the dialer idle-timeout command to set a high idle timer. The dialer-load threshold 1 command does not keep a multilink bundle of n links connected indefinitely, and the dialer-load threshold 2 command does not keep a multilink bundle of two links connected indefinitely.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface bri number

4. ip address ip-address mask [secondary]

5. encapsulation ppp

6. dialer idle-timeout seconds [inbound | either]

7. dialer load-threshold load

8. dialer map protocol next-hop-address [name hostname] [spc] [speed 56 | 64] [broadcast] [dial-string[:isdn-subaddress]]

9. dialer-group group-number

10. ppp authentication pap

11. ppp multilink

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface bri number

Device(config)# interface bri 1

Specifies an interface and benters interface configuration mode.

Step 4

ip address ip-address mask [secondary]

Device(config-if)# ip address 192.0.2.0 255.255.255.224

Provides an appropriate protocol address for the interface.

Step 5

encapsulation ppp

Device(config-if)# encapsulation ppp

Enables PPP encapsulation.

Step 6

dialer idle-timeout seconds [inbound | either]

Device(config-if)# dialer idle-timeout 60

Specifies the duration of idle time in seconds after which a line will be disconnected.

- By default, outbound traffic will reset the dialer idle timer. Adding the either keyword causes both inbound and outbound traffic to reset the timer; adding the inbound keyword causes only inbound traffic to reset the timer.

Step 7

dialer load-threshold load

Device(config-if)# dialer load-threshold 60

Specifies the dialer load threshold for bringing up additional WAN links.

Step 8

dialer map protocol next-hop-address [name hostname] [spc] [speed 56 | 64] [broadcast] [dial-string[:isdn-subaddress]]

Device(config-if)# dialer map protocol 192.0.2.1

Configures the ISDN interface to call the remote site.

Step 9

dialer-group group-number

Device(config-if)# dialer-group 3

Controls access to this interface by adding it to a dialer access group.

Step 10

ppp authentication pap

Device(config-if)# ppp authentication pap

(Optional) Enables PPP authentication.

Step 11

ppp multilink

Device(config-if)# ppp multilink

Configures MLP on the dialer rotary group.

Configuring MLP on Multiple ISDN BRI Interfaces

To enable MLP on multiple ISDN BRI interfaces, set up a dialer rotary interface and configure it for Multilink PPP, and then configure the BRI interfaces separately and add them to the same rotary group.

To set up the dialer rotary interface for the BRI interfaces, perform the following task:

SUMMARY STEPS

1. enable

2. configure terminal

3. interface dialer number

4. ip address address mask

5. encapsulation ppp

6. dialer in-band

7. dialer idle-timeout seconds [inbound | either]

8. dialer map protocol next-hop-address [name hostname] [spc] [speed 56 | 64] [broadcast] [dial-string[:isdn-subaddress]]

9. dialer rotary-group number

10. dialer load-threshold load

11. dialer-group number

12. ppp authentication chap

13. ppp multilink

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface dialer number

Device(config)# interface dialer 1

Specifies the dialer rotary interface and enters interface configuration mode.

Step 4

ip address address mask

Device(config-if)# ip address 192.0.2.0 255.255.255.224

Specifies the protocol address for the dialer rotary interface.

Step 5

encapsulation ppp

Device(config-if)# encapsulation ppp

Enables PPP encapsulation.

Step 6

dialer in-band

Device(config-if)# dialer in-band

Specifies in-band dialing.

Step 7

dialer idle-timeout seconds [inbound | either]

Device(config-if)# dialer idle-timeout 60

Specifies the duration of idle time in seconds after which a line will be disconnected.

- By default, outbound traffic will reset the dialer idle timer. Adding the either keyword causes both inbound and outbound traffic to reset the timer; adding the inbound keyword causes only inbound traffic to reset the timer.

Step 8

dialer map protocol next-hop-address [name hostname] [spc] [speed 56 | 64] [broadcast] [dial-string[:isdn-subaddress]]

Device(config-if)# dialer map protocol 192.0.2.1

Maps the next hop protocol address and name to the dial string needed to reach it.

Step 9

dialer rotary-group number

Device(config-if)# dialer rotary-group 1

Adds the interface to the rotary group.

Step 10

dialer load-threshold load

Device(config-if)# dialer load-threshold 2

Specifies the dialer load threshold, using the same threshold as the individual BRI interfaces.

Step 11

dialer-group number

Device(config-if)# dialer-group 2

Controls access to the interface by adding it to a dialer access group.

Step 12

ppp authentication chap

Device(config-if)# ppp authentication chap

(Optional) Enables PPP CHAP authentication.

Step 13

ppp multilink

Device(config-if)# ppp multilink

Enables Multilink PPP.

If you do not use PPP authentication procedures (Step 10), your telephone service must pass caller ID information.

Repeat Steps 1 through 9 for each BRI that you want to belong to the same dialer rotary group.

When MLP is configured and you want a multilink bundle to be connected indefinitely, use the dialer idle-timeout command to set a very high idle timer. The dialer load-threshold 1 command does not keep a multilink bundle of n links connected indefinitely and the dialer load-threshold 2 command does not keep a multilink bundle of two links connected indefinitely.)

Note Prior to Cisco IOS Release 12.1, when MLP was used in a dialer profile, a virtual access interface was always created as the bundle. It was bound to both the B channel and the dialer profile interfaces after creation and cloning. The dialer profile interface could act as the bundle without help from a virtual access interface. But with the Dynamic Multiple Encapsulations feature available in Cisco IOS Release 12.1, it is no longer the virtual access interface that is added into the connected group of the dialer profile, but the dialer profile itself. The dialer profile becomes a connected member of its own connected group. See the “Dynamic Multiple Encapsulations over ISDN Example” in the module “Configuring Peer-to-Peer DDR with Dialer Profiles” in this module, for more information about dynamic multiple encapsulations and its relation to Multilink PPP.

For an example of configuring MLP on multiple ISDN BRI interfaces, see the section “Example: MLP on Multiple ISDN BRI Interfaces” section.

Configuring MLP Using Multilink Group Interfaces

MLP can be configured by assigning a multilink group to a virtual template configuration. Virtual templates allow a virtual access interface to dynamically clone interface parameters from the specified virtual template. If a multilink group is assigned to a virtual template, and then the virtual template is assigned to a physical interface, all links that pass through the physical interface will belong to the same multilink bundle.

Note If a multilink group interface has one member link, the amount of bandwidth available will not change when a multilink interface is shut down. Therefore, you can shut down the multilink interface by removing its link.

A multilink group interface configuration will override a global multilink virtual template configured with the multilink virtual template command.

Multilink group interfaces can be used with ATM, PPP over Frame Relay, and serial interfaces.

To configure MLP using a multilink group interface, perform the following tasks:

- Configure the multilink group.

- Assign the multilink group to a virtual template.

- Configure the physical interface to use the virtual template.

Perform the following tasks in this section to configure the multilink group. For an example of how to configure MLP over an ATM PVC using a multilink group, see the section “Example: MLP Using Multilink Group Interfaces over ATM” section.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface multilink group-number

4. ip address address mask

5. encapsulation ppp

6. exit

7. interface virtual template number

8. ppp multilink group group-number

9. exit

10. interface atm interface-number.subinterface-number point-to-point

11. pvc vpi/vli

12. protocol ppp virtual-template name

13. end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface multilink group-number

Device(config)# interface multilink 2

Creates a multilink bundle and enters interface configuration mode to configure the bundle.

Step 4

ip address address mask

Device(config-if)# ip address 192.0.2.1 255.255.255.224

Sets a primary IP address for an interface.

Step 5

encapsulation ppp

Device(config-if)# encapsulation ppp

Enables PPP encapsulation.

Step 6

exit

Device(config-if)# exit

Exits interface configuration mode.

Step 7

interface virtual template number

Device(config)# interface virtual template 1

Creates a virtual template interface that can be configured and applied dynamically in creating virtual access interfaces, and enters interface configuration mode.

Step 8

ppp multilink group group-number

Device(config-if)# ppp multilink group 2

Restricts a physical link to joining only a designated multilink group interface.

Step 9

exit

Device(config-if)# exit

Exits interface configuration mode.

Step 10

interface atm interface-number.subinterface-number point-to-point

Device(config)# interface atm 1.2 point-to-point

Configures an ATM interface and enters interface configuration mode.

Step 11

pvc vpi/vci

Device(config-if)# pvc 1/100

Creates or assigns a name to an ATM permanent virtual circuit (PVC), specifies the encapsulation type on an ATM PVC, and enters ATM virtual circuit configuration mode.

Step 12

protocol ppp virtual-template name

Device(config-if-atm-vc)# protocol ppp virtual-template 2

Configures VC multiplexed encapsulation on a PVC.

Step 13

end

Device(config-if-atm-vc)# end

Exits ATM virtual circuit configuration mode.

Changing the Default Endpoint Discriminator

By default, when the system negotiates use of MLP with the peer, the value that is supplied for the endpoint discriminator is the same as the username used for authentication. That username is configured for the interface by the Cisco IOS ppp chap hostname or ppp pap sent-username command, or defaults to the globally configured hostname (or stack group name, if this interface is a Stack Group Bidding Protocol, or SGBP, group member).

Perform this task to override or change the default endpoint discriminator. For an example of how to change the default endpoint discriminator, see the “Example: Changing the Default Endpoint Discriminator” section.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface virutal template number

4. ppp multilink endpoint {hostname | ip ipaddress | mac LAN-interface | none | phone telephone-number | string char-string}

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface virtual template number

Device(config)# interface virtual template 1

Creates a virtual template interface that can be configured and applied dynamically in creating virtual access interfaces and enters interface configuration mode.

Step 4

ppp multilink endpoint {hostname | ip ipaddress | mac LAN-interface | none | phone telephone-number | string char-string}

Device(config-if)# ppp multilink endpoint ip 192.0.2.0

Overrides or changes the default endpoint discriminator the system uses when negotiating the use of MLP with the peer.

Configuring MLP Interleaving

Perform the following tasks to configure MLP and interleaving on a configured and operational interface or virtual interface template.

Configuring MLP Interleaving and Queueing

Interleaving on MLP allows large packets to be multilink encapsulated and fragmented into a small enough size to satisfy the delay requirements of real-time traffic; small real-time packets are not multilink encapsulated and are sent between fragments of the large packets. The interleaving feature also provides a special transmit queue for the smaller, delay-sensitive packets, enabling them to be sent earlier than other flows.

Weighted fair queueing on MLP works on the packet level, not at the level of multilink fragments. Thus, if a small real-time packet gets queued behind a larger best-effort packet and no special queue has been reserved for real-time packets, the small packet will be scheduled for transmission only after all the fragments of the larger packet are scheduled for transmission.

Weighted fair queueing is supported on all interfaces that support Multilink PPP, including MLP virtual access interfaces and virtual interface templates. Weighted fair queueing is enabled by default.

Fair queueing on MLP overcomes a prior restriction. Previously, fair queueing was not allowed on virtual access interfaces and virtual interface templates. Interleaving provides the delay bounds for delay-sensitive voice packets on a slow link that is used for other best-effort traffic.

Interleaving applies only to interfaces that can configure a multilink bundle interface. These restrictions include virtual templates, dialer interfaces, and ISDN BRI or PRI interfaces.

Multilink and fair queueing are not supported when a multilink bundle is off-loaded to a different system using Multichassis Multilink PPP (MMP). Thus, interleaving is not supported in MMP networking designs.

MLP support for interleaving can be configured on virtual templates, dialer interfaces, and ISDN BRI or PRI interfaces. To configure interleaving, complete the following tasks:

- Configure the dialer interface, BRI interface, PRI interface, or virtual template.

- Configure MLP and interleaving on the interface or template.

Note Fair queueing, which is enabled by default, must remain enabled on the interface.

Note Interleaving statistics can be displayed by using the show interfaces command, specifying the particular interface on which interleaving is enabled. Interleaving data is displayed only if there are interleaves. For example, the following line shows interleaves: Output queue: 315/64/164974/31191 (size/threshold/drops/interleaves)

SUMMARY STEPS

1. enable

2. configure terminal

3. interface virtual template number

4. ppp multilink

5. ppp multilink interleave

6. ppp multilink fragment delay milliseconds

7. ip rtp reserve lowest-udp-port range-of-ports [maximum-bandwidth]

8. exit

9. multilink virtual-template virtual-template-number

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface virtual template number

Device(config)# interface virtual template 1

Creates a virtual template interface that can be configured and applied dynamically in creating virtual access interfaces, and enters interface configuration mode.

Step 4

ppp multilink

Device(config-if)# ppp multilink

Enables Multilink PPP.

Step 5

ppp multilink interleave

Device(config-if)# configure terminal

Enables interleaving of packets among the fragments of larger packets on an MLP bundle.

Step 6

ppp multilink fragment delay milliseconds

Device(config-if)# ppp multilink fragment delay 50

Specifies a maximum size, in units of time, for packet fragments on an MLP bundle.

Step 7

ip rtp reserve lowest-udp-port range-of-ports [maximum-bandwidth]

Device(config-if)# ip rtp reserve 1 2

Reserves a special queue for real-time packet flows to specified destination UDP ports, allowing real-time traffic to have higher priority than other flows.

Step 8

exit

Device(config-if)# exit

Exits interface configuration mode.

Step 9

multilink virtual-template virtual-template-number

Device(config)# multilink virtual-template 1

For virtual templates only, applies the virtual template to the multilink bundle.

Note This step is not used for ISDN or dialer interfaces.

Configuring MLP Inverse Multiplexer and Distributed MLP

The distributed MLP (dMLP) feature combines T1/E1 lines in a WAN line card on a Cisco 7600 series router into a bundle that has the combined bandwidth of the multiple T1/E1 lines. You choose the number of bundles and the number of T1/E1 lines in each bundle, which allows you to increase the bandwidth of your network links beyond that of a single T1/E1 line without having to purchase a T3 line.

Nondistributed MLP is not supported on the Cisco 7600 series router. With distributed MLP, you can increase the router’s total capacity.

The MLP Inverse Multiplexer feature was designed for Internet service providers (ISPs) that want to have the bandwidth of multiple T1 lines with performance comparable to that of an inverse multiplexer without the need of buying standalone inverse-multiplexing equipment. A Cisco router supporting dMLP can bundle multiple T1 lines in a CT3 or CE3 interface or channelized STM1. Bundling is more economical than purchasing an inverse multiplexer, and eliminates the need to configure another piece of equipment.

This feature supports the CT3 CE3 data rates without taxing the Route Processor (RP) and CPU by moving the data path to the line card. This feature also allows remote sites to purchase multiple T1 lines instead of a T3 line, which is especially useful when the remote site does not need the bandwidth of an entire T3 line.

This feature allows multilink fragmentation to be disabled, so multilink packets are sent using Cisco Express Forwarding on all platforms, if fragmentation is disabled. Cisco Express Forwarding is supported with fragmentation enabled or disabled.

Note If a router cannot send out all the packets (some packets are dropped by Quality of Service (QoS)), late drops occur. These late drops are displayed when the show interface command is executed.

If there is no service policy on the dMLP interface, when a ppp multilink interleave is configured on the dMLPPP interface, a QoS policy is enabled internally.

Figure 2 shows a typical network using a dMLP link. The Cisco 7600 series router is connected to the network with a CT3 line that has been configured with dMLPP to carry two bundles of four T1 lines each. One of these bundles goes out to a Cisco 2500 series router and the other goes out to a Cisco 3800 series router.

Figure 2 Diagram of a Typical VIP MLP Topology

Before beginning the MLP Inverse Multiplexer configuration tasks, make note of the following prerequisites and restrictions.

Prerequisites

- Distributed Cisco Express Forwarding switching must be enabled for distributed MLP.

- One of the following port adapters is required:

– CT3IP

– PA-MC-T3

– PA-MC-2T3+

– PA-MC-E3

– PA-MC-8T1

– PA-MC-4T1

– PA-MC-8E1

- All 16 E1s can be bundled from a PA-MC-E3 in a VIP4-80.

Restrictions

The following restrictions apply to the dMLP feature:

Note Distributed MLP is supported only for member links configured at T1/E1 or subrate T1/E1 speeds. Channelized STM-1/T3/T1 interfaces also support dMLP at T1/E1 or subrate T1/E1 speeds. Distributed MLP is not supported for member links configured at clear-channel T3/E3 or higher interface speeds.

- T1 and E1 lines cannot be mixed in a bundle.

- T1 lines in a bundle should have the same bandwidth.

- All lines in a bundle must reside on the same port adapter.

- MLP bundles across FlexWAN or Enhanced FlexWAN port adapters are not supported.

- Hardware compression is not supported.

- Encryption is not supported.

- Software compression is not recommended because CPU usage would void performance gains.

- The maximum differential delay supported is 50 milliseconds (ms).

- Fragmentation is not supported on the transmit side.

- dMLP across shared port adapters (SPAs) is not supported.

- Hardware and software compression is not supported.

- Encryption is not supported.

- The maximum differential delay supported is 50 ms when supported in hardware, and 100 ms when supported in software.

Enabling fragmentation reduces the delay latency among bundle links, but adds some load to the CPU. Disabling fragmentation may result in better throughput.

If your data traffic is consistently of a similar size, we recommend disabling fragmentation. In this case, the benefits of fragmentation may be outweighed by the added load on the CPU.

To configure a multilink bundle, perform the tasks in the following sections:

- Creating a Multilink Bundle (required)

- Assigning an Interface to a Multilink Bundle (required)

- Disabling PPP Multilink Fragmentation (optional)

Creating a Multilink Bundle

Perform the following tasks to create a multilink bundle.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface multilink group-number

4. ip address address mask

5. encapsulation ppp

6. ppp multilink

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface multilink group-number

Device(config)# interface multilink 10

Assigns a multilink group number and enters interface configuration mode.

Step 4

ip address address mask

Device(config-if)# ip address 192.0.2.9 255.255.255.224

Assigns an IP address to the multilink interface.

Step 5

encapsulation ppp

Device(config-if)# encapsulation ppp

Enables PPP encapsulation.

Step 6

ppp multilink

Device(config-if)# ppp multilink

Enables Multilink PPP.

Assigning an Interface to a Multilink Bundle

Perform this task to assign an interface to a multilink bundle.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface multilink group number

4. no ip address

5. keepalive

6. encapsulation ppp

7. ppp multilink group group-number

8. ppp multilink

9. ppp authentication chap

10. pulse-time seconds

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface multilink group-number

Device(config)# interface multilink 10

Assigns a multilink group number and enters interface configuration mode.

Step 4

no ip address

Device(config-if)# no ip address

Removes any specified IP address.

Step 5

keepalive

Device(config-if)# keepalive

Sets the frequency of keepalive packets.

Step 6

encapsulation ppp

Device(config-if)# encapsulation ppp

Enables PPP encapsulation.

Step 7

ppp multilink group group-number

Device(config-if)# ppp multilink 12

Restricts a physical link to joining only the designated multilink-group interface.

Step 8

ppp multilink

Device(config-if)# ppp multilink

Enables Multilink PPP.

Step 9

ppp authentication chap

Device(config-if)# ppp authentication chap

(Optional) Enables CHAP authentication.

Step 10

pulse-time seconds

Device(config-if)# pulse-time 10

(Optional) Configures DTR signal pulsing.

Caution Do not install a router to the peer address while configuring an MLP lease line. This installation can be disabled when no ppp peer-neighbor-route command is used under the MLPPP bundle interface.

Disabling PPP Multilink Fragmentation

Perform the following task to disable PPP multilink fragmentation.

SUMMARY STEPS

1. enable

2. configuration terminal

3. interface multilink group number

4. ppp multilink fragment disable

5. exit

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Device# configure terminal

Enters global configuration mode.

Step 3

interface multilink group-number

Device(config)# interface multilink 10

Assigns a multilink group number and enters interface configuration mode.

Step 4

ppp multilink fragment disable

Device(config-if)# ppp multilink fragment disable

(Optional) Disables PPP multilink fragmentation.

Step 5

exit

Device(config-if)# exit

Exits privileged EXEC mode.

Monitoring and Maintaining PPP and MLP Interfaces

Perform this task to display MLP and MMP bundle information.

SUMMARY STEPS

1. enable

2. show ppp multilink

3. exit

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

show ppp multilink

Device# show ppp multilink

Displays MLP and MMP bundle information.

Step 3

exit

Device# exit

Exits privileged EXEC mode.

Configuration Examples for PPP and MLP

The following sections provide various PPP configuration examples:

- Examples: CHAP with an Encrypted Password:

- Example: DHCP Network Control

- Example: IP Address Pooling

- Example: MPPC Interface Configuration

- Examples: MLP

- Example: MLP Interleaving and Queueing for Real-Time Traffic

- Example: Multilink Interface Configuration for Distributed MLP

- Example: PAP commands for a one way authentication

- Example: T3 Controller Configuration for an MLP Multilink Inverse Multiplexer

- Example: User Maximum Links Configuration

Examples: CHAP with an Encrypted Password:

The following examples show how to enable CHAP on serial interface 0 of three devices:

Configuration of Device yyy

hostname yyy

interface serial 0

encapsulation ppp

ppp authentication chap

username xxx password secretxy

username zzz password secretzy

Configuration of Device xxx

hostname xxx

interface serial 0

encapsulation ppp

ppp authentication chap

username yyy password secretxy

username zzz password secretxz

Configuration of Device zzz

hostname zzz

interface serial 0

encapsulation ppp

ppp authentication chap

username xxx password secretxz

username yyy password secretzy

When you look at the configuration file, the passwords are encrypted and the display looks similar to the following:

hostname xxx

interface serial 0

encapsulation ppp

ppp authentication chap

username yyy password 7 121F0A18

username zzz password 7 1329A055

Example: Changing the Default Endpoint Discriminator

The following partial example changes the MLP endpoint discriminator from the default CHAP hostname C-host1 to the E.164-compliant telephone number 555-0100:

.

.

.

interface dialer 0

ip address 10.1.1.4 255.255.255.0

encapsulation ppp

dialer remote-name R-host1

dialer string 23456

dialer pool 1

dialer-group 1

ppp chap hostname C-host1

ppp multilink endpoint phone 555-0100

.

.

.

Example: DHCP Network Control

The following partial example shows how to add the ip dhcp-client network-discovery command to the “Example: IP Address Pooling” section to allow peer routers to more dynamically discover DNS and NetBIOS name servers. If the ip dhcp-client network-discovery command is disabled, the system falls back to the static configurations made using the async-bootp dns-server and async-bootp nb-server global configuration commands.

!

hostname secret

!

aaa new-model

aaa authentication login default local

aaa authentication ppp default if-needed local

aaa authentication ppp chap local

enable secret 5 encrypted-secret

enable password EPassWd1

!

username User1 password 0 PassWd2

username User2 password 0 PassWd3

username User3 password 0 PassWd4

no ip domain-lookup

ip dhcp-server 10.47.0.131

ip dhcp-client network-discovery informs 2 discovers 2 period 12

async-bootp gateway 10.47.0.1

async-bootp nbns-server 10.47.0.131

isdn switch-type primary-4ess

.

.

.

Example: IP Address Pooling

The following example shows how to configure a modem to dial in to a Cisco access server and obtain an IP address from the DHCP server. This configuration allows the user to log in and browse an NT network. Notice that the dialer 1 and group-async 1 interfaces are configured with the ip unnumbered loopback command, so that the broadcast can find the dialup clients and the client can see the NT network.

!

hostname secret

!

aaa new-model

aaa authentication login default local

aaa authentication ppp default if-needed local

aaa authentication ppp chap local

enable secret 5 encrypted-secret

enable password EPassWd1

!

username User1 password 0 PassWd2

username User2 password 0 PassWd3

username User3 password 0 PassWd4

no ip domain-lookup

ip dhcp-server 10.47.0.131

async-bootp gateway 10.47.0.1

async-bootp nbns-server 10.47.0.131

isdn switch-type primary-4ess

!

!

controller t1 0

framing esf

clock source line primary

linecode b8zs

pri-group timeslots 1-24

!

controller t1 1

framing esf

clock source line secondary

linecode b8zs

!

interface loopback 0

ip address 10.47.252.254 255.255.252.0

!

interface ethernet 0

ip address 10.47.0.5 255.255.252.0

ip helper-address 10.47.0.131

ip helper-address 10.47.0.255

no ip route-cache

no ip mroute-cache

!

interface serial 0

no ip address

no ip mroute-cache

shutdown

!

interface serial 1

no ip address

shutdown

!

interface serial 0:23

no ip address

encapsulation ppp

no ip mroute-cache

dialer rotary-group 1

dialer-group 1

isdn incoming-voice modem

no fair-queue

no cdp enable

!

interface group-async 1

ip unnumbered loopback 0

ip helper-address 10.47.0.131

ip tcp header-compression passive

encapsulation ppp

no ip route-cache

no ip mroute-cache

async mode interactive

peer default ip address dhcp

no fair-queue

no cdp enable

ppp authentication chap

group-range 1 24

!

interface dialer 1

ip unnumbered loopback 0

encapsulation ppp

dialer in-band

dialer-group 1

no peer default ip address

no fair-queue

no cdp enable

ppp authentication chap

ppp multilink

!

router ospf 172

redistribute connected subnets

redistribute static

network 10.47.0.0 0.0.3.255 area 0

network 10.47.156.0 0.0.3.255 area 0

network 10.47.168.0 0.0.3.255 area 0

network 10.47.252.0 0.0.3.255 area 0

!

ip local pool RemotePool 10.47.252.1 10.47.252.24

ip classless

ip route 10.0.140.0 255.255.255.0 10.59.254.254

ip route 10.2.140.0 255.255.255.0 10.59.254.254

ip route 10.40.0.0 255.255.0.0 10.59.254.254

ip route 10.59.254.0 255.255.255.0 10.59.254.254

ip route 172.23.0.0 255.255.0.0 10.59.254.254

ip route 192.168.0.0 255.255.0.0 10.59.254.254

ip ospf name-lookup

no logging buffered

access-list 101 deny ip any host 255.255.255.255

access-list 101 deny ospf any any

access-list 101 permit ip any any

dialer-list 1 protocol ip list 101

snmp-server community public RO

!

line con 0

line 1 24

autoselect during-login

autoselect ppp

modem InOut

transport input all

line aux 0

line vty 0 4

password Password

!

scheduler interval 100

end

Example: MPPC Interface Configuration

The following example shows how to configure asynchronous interface 1 to implement MPPC and ignore the protocol field compression flag negotiated by LCP:

interface async1

ip unnumbered ethernet0

encapsulation ppp

async default routing

async dynamic routing

async mode interactive

peer default ip address 172.21.71.74

compress mppc ignore-pfc

The following example creates a virtual access interface (virtual template interface 1) and serial interface 0, which is configured for X.25 encapsulation. MPPC values are configured on the virtual template interface and will ignore the negotiated protocol field compression flag.

interface ethernet0

ip address 172.20.30.102 255.255.255.0

!

interface virtual-template1

ip unnumbered ethernet0

peer default ip address pool vtemp1

compress mppc ignore-pfc

!

interface serial0

no ipaddress

no ip mroute-cache

encapsulation x25

x25 win 7

x25 winout 7

x25 ips 512

x25 ops 512

clock rate 50000

!

ip local pool vtemp1 172.20.30.103 172.20.30.104

ip route 0.0.0.0 0.0.0.0 172.20.30.1

!

translate x25 31320000000000 virtual-template 1

Examples: MLP

This section contains the following MLP examples:

- Example: MLP on Synchronous Serial Interfaces

- Example: MLP on One ISDN BRI Interface

- Example: MLP on Multiple ISDN BRI Interfaces

- Example: MLP Inverse Multiplexer Configuration

- Example: MLP Using Multilink Group Interfaces over ATM

- Example: Changing the Default Endpoint Discriminator

Example: MLP on Synchronous Serial Interfaces

The following example shows how the configuration commands are used to create the inverse multiplexing application:

Device A Configuration

hostname DeviceA

!

!

username DeviceB password your_password

ip subnet-zero

multilink virtual-template 1

!

interface Virtual-Template1

ip unnumbered Ethernet0

ppp authentication chap

ppp multilink

!

interface Serial0

no ip address

encapsulation ppp

no fair-queue

ppp multilink

pulse-time 3

!

interface Serial1

no ip address

encapsulation ppp

no fair-queue

ppp multilink

pulse-time 3

!

interface Serial2

no ip address

encapsulation ppp

no fair-queue

ppp multilink

pulse-time 3

!

interface Serial3

no ip address

encapsulation ppp

no fair-queue

ppp multilink

pulse-time 3

!

interface Ethernet0

ip address 10.17.1.254 255.255.255.0

!

router rip

network 10.0.0.0

!

end

Device B Configuration

hostname DeviceB

!

!

username DeviceB password your_password

ip subnet-zero

multilink virtual-template 1

!

interface Virtual-Template1

ip unnumbered Ethernet0

ppp authentication chap

ppp multilink

!

interface Serial0

no ip address

encapsulation ppp

no fair-queue

ppp multilink

pulse-time 3

!

interface Serial1

no ip address

encapsulation ppp

no fair-queue

ppp multilink

pulse-time 3

!

interface Serial2

no ip address

encapsulation ppp

no fair-queue

ppp multilink

pulse-time 3

!

interface Serial3

no ip address

encapsulation ppp

no fair-queue

ppp multilink

pulse-time 3

!

interface Ethernet0

ip address 10.17.2.254 255.255.255.0

!

router rip

network 10.0.0.0

!

end

Example: MLP on One ISDN BRI Interface

The following example shows how to enable MLP on BRI interface 0. When a BRI is configured, no dialer rotary group configuration is required, because an ISDN interface is a rotary group by default.

interface bri 0

description connected to ntt 81012345678902

ip address 172.31.1.7 255.255.255.0

encapsulation ppp

dialer idle-timeout 30

dialer load-threshold 40 either

dialer map ip 172.31.1.8 name user1 81012345678901

dialer-group 1

ppp authentication pap

ppp multilink

Example: MLP on Multiple ISDN BRI Interfaces

The following example shows how to configure multiple ISDN BRI interfaces to belong to the same dialer rotary group for Multilink PPP. The dialer rotary-group command is used to assign each of the ISDN BRI interfaces to that dialer rotary group.

interface BRI 0

no ip address

encapsulation ppp

dialer idle-timeout 500

dialer rotary-group 0

dialer load-threshold 30 either

!

interface BRI 1

no ip address

encapsulation ppp

dialer idle-timeout 500

dialer rotary-group 0

dialer load-threshold 30 either

!

interface BRI 2

no ip address

encapsulation ppp

dialer idle-timeout 500

dialer rotary-group 0

dialer load-threshold 30 either

!

interface Dialer 0

ip address 10.0.0.2 255.0.0.0

encapsulation ppp

dialer in-band

dialer idle-timeout 500

dialer map ip 10.0.0.1 name user1 broadcast 81012345678901

dialer load-threshold 30 either

dialer-group 1

ppp authentication chap

ppp multilink

Example: MLP Using Multilink Group Interfaces over ATM

The following example shows how to configure MLP over an ATM PVC using a multilink group:

interface multilink 1

ip address 10.200.83.106 255.255.255.252

ip tcp header-compression iphc-format delay 20000

service policy output xyz

encapsulation ppp

exit

ppp multilink

ppp multilink fragment delay 10

ppp multilink interleave

ppp timeout multilink link remove 10

ip rtp header-compression iphc-format

interface virtual-template 3

bandwidth 128

ppp multilink group 1

interface atm 4/0.1 point-to-point

pvc 0/32

abr 100 80

protocol ppp virtual-template 3

Example: MLP Inverse Multiplexer Configuration

This example shows how to verify the display information of the newly created multilink bundle:

Device# show ppp multilink

Multilink1, bundle name is group1

Bundle is Distributed

0 lost fragments, 0 reordered, 0 unassigned, sequence 0x0/0x0 rcvd/sent

0 discarded, 0 lost received, 1/255 load

Member links:4 active, 0 inactive (max not set, min not set)

Serial1/0/0:1

Serial1/0/0/:2

Serial1/0/0/:3

Serial1/0/0/:4

Example: MLP Interleaving and Queueing for Real-Time Traffic

The following example defines a virtual interface template that enables MLP interleaving and a maximum real-time traffic delay of 20 milliseconds, and then applies that virtual template to the MLP bundle:

interface virtual-template 1

ip unnumbered ethernet 0

ppp multilink

ppp multilink interleave

ppp multilink fragment delay 20

ip rtp interleave 32768 20 1000

multilink virtual-template 1

The following example enables MLP interleaving on a dialer interface that controls a rotary group of BRI interfaces. This configuration permits IP packets to trigger calls.

interface BRI 0

description connected into a rotary group

encapsulation ppp

dialer rotary-group 1

!

interface BRI 1

no ip address

encapsulation ppp

dialer rotary-group 1

!

interface BRI 2

encapsulation ppp

dialer rotary-group 1

!

interface BRI 3

no ip address

encapsulation ppp

dialer rotary-group 1

!

interface BRI 4

encapsulation ppp

dialer rotary-group 1

!

interface Dialer 0

description Dialer group controlling the BRIs

ip address 10.1.1.1 255.255.255.0

encapsulation ppp

dialer map ip 10.1.1.2 name name1 14802616900

dialer-group 1

ppp authentication chap

! Enables Multilink PPP interleaving on the dialer interface and reserves

! a special queue.

ppp multilink

ppp multilink interleave

ip rtp reserve 32768 20 1000

! Keeps fragments of large packets small enough to ensure delay of 20 ms or less.

ppp multilink fragment delay 20

dialer-list 1 protocol ip permit

Example: Multilink Interface Configuration for Distributed MLP

In the following example, four multilink interfaces are created with distributed Cisco Express Forwarding switching and MLP enabled. Each of the newly created interfaces is added to a multilink bundle.

interface multilink1

ip address 10.0.0.0 10.255.255.255

ppp chap hosstname group 1

ppp multilink

ppp multilink group 1

interface serial 1/0/0:1

no ip address

encapsulation ppp

ip route-cache distributed

no keepalive

ppp multilink

ppp multilink group 1

interface serial 1/0/0:2

no ip address

encapsulation ppp

ip route-cache distributed

no keepalive

ppp chap hostname group 1

ppp multilink

ppp multilink group 1

interface serial 1/0/0:3

no ip address

encapsulation ppp

ip route-cache distributed

no keepalive

ppp chap hostname group 1

ppp multilink

ppp multilink group 1

interface serial 1/0/0:4

no ip address

encapsulation ppp

ip route-cache distributed

no keepalive

ppp chap hostname group 1

ppp multilink

ppp multilink group 1

Example: PAP commands for a one way authentication

The following example shows how to authenticate PAP commands for a one way authentication scenario:

Note Only the relevant sections of the configuration are shown.

Calling Side (Client) Configuration

interface BRI0

! --- BRI interface for the dialout.

ip address negotiated

encapsulation ppp

! --- Use PPP encapsulation. This command is a required for PAP.

dialer string 3785555 class 56k

! --- Number to dial for the outgoing connection.

dialer-group 1

isdn switch-type basic-ni

isdn spid1 51299611110101 9961111

isdn spid2 51299622220101 9962222

ppp authentication pap callin

! --- Use PAP authentication for incoming calls.

! --- The callin keyword has made this a one-way authentication scenario.

! --- This router (client) will not request that the peer (server) authenticate

! --- itself back to the client.

ppp pap sent-username PAPUSER password 7 <deleted>

! --- Permit outbound authentication of this router (client) to the peer.

! --- Send a PAP AUTH-REQ packet to the peer with the username PAPUSER and password.

! --- The peer must have the username PAPUSER and password configured on it.

Receiving Side (Server) Configuration

username PAPUSER password 0 cisco

! --- Username PAPUSER is the same as the one sent by the client.

! --- Upon receiving the AUTH-REQ packet from the client, we will verify that the

! --- username and password match the one configured here.

interface Serial0:23

! --- This is the D-channel for the PRI on the access server receiving the call.

ip unnumbered Ethernet0

no ip directed-broadcast

encapsulation ppp

! --- Use PPP encapsulation. This command is a required for PAP.

dialer-group 1

isdn switch-type primary-ni

isdn incoming-voice modem

peer default ip address pool default

fair-queue 64 256 0

ppp authentication pap

! --- Use PAP authentication for incoming calls.

! --- This router (server) will request that the peer authenticate itself to us.

! --- Note: the callin option is not used as this router is not initiating the call.

Example: T3 Controller Configuration for an MLP Multilink Inverse Multiplexer

The following example shows how to configure the T3 controller and create four channelized interfaces:

controller T3 1/0/0

framing m23

cablelength 10

t1 1 timeslots 1-24

t1 2 timeslots 1-24

t1 3 timeslots 1-24

t1 4 timeslots 1-24

Example: User Maximum Links Configuration

The following example shows how to configure the username user1 and establish a maximum of five connections. user1 can connect through serial interface 1/0, which has a dialer map configured for it, or through PRI interface 0/0:23, which has dialer profile interface 0 dedicated to it.

The aaa authorization network default local command must be configured. PPP encapsulation and authentication must be enabled on all the interfaces that user1 can connect to.

aaa new-model

aaa authorization network default local

enable secret password1

enable password password2

!

username user1 user-maxlinks 5 password password3

!

interface Serial0/0:23

no ip address

encapsulation ppp

dialer pool-member 1

ppp authentication chap

ppp multilink

!

interface Serial1/0

ip address 209.165.201.1 255.255.255.0

encapsulation ppp

dialer in-band

dialer map ip 10.2.2.13 name user1 12345

dialer-group 1

ppp authentication chap

!

interface Dialer0

ip address 209.165.200.225 255.255.255.0

encapsulation ppp

dialer remote-name user1

dialer string 23456

dialer pool 1

dialer-group 1

ppp authentication chap

ppp multilink

!

dialer-list 1 protocol ip permit

Additional References

The following sections provide references related to the Configuring Media-Independent PPP and Multilink PPP feature.

Related Documents

Related Topic

Document Title

Asynchronous SLIP and PPP

“Configuring Asynchronous SLIP and PPP” module in the Cisco IOS Dial Technologies Configuration Guide

MCHAP

MS-CHAP Support

Dial commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples

Cisco IOS Dial Technologies Command Reference.

RFCs

RFC

Title

RFC 1994

PPP Challenge Handshake Authentication Protocol (CHAP)

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/techsupport

Feature Information for Configuring Media-Independent PPP and Multilink PPP

Table 1 lists the release history for this feature.

Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Note Table 1 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.

Table 1 Feature Information for Configuring Media-Independent PPP and Multilink PPP

Feature Name

Releases

Feature Information

Multilink PPP

11.2(1)

12.2(8)T

11.2(6)P

12.1(3)T

12.3(13)BC

12.2(27)SBB

12.2(31)SB2

15.0(1)M

12.2(33)SRE

15.2(2)S

Cisco IOS XE Release 3.14S

Multilink PPP provides a method for spreading traffic across multiple physical WAN links.

The following sections provide information about this feature:

- Information About Media-Independent PPP and Multilink PPP

- How to Configure Media-Independent PPP and Multilink PPP

The following commands were introduced or modified:

ppp multilink, ppp multilink group.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2001–2012 Cisco Systems, Inc. All rights reserved.

Customer Profile Idle Timer Enhancements for Interesting Traffic

Feature History

Release

Modification

12.2(4)T

This feature was introduced.

12.2(11)T

This feature was implemented on Cisco access server platforms.

This document describes the Asynchronous Line Monitoring feature feature. It includes the following sections:

- Feature Overview

- Supported Platforms

- Supported Standards, MIBs, and RFCs

- Configuration Tasks

- Configuration Examples

- Command Reference

- Glossary

Feature Overview

Before Cisco IOS Release 12.2(4)T, only the dialer idle timer could be reset for interesting traffic on a dialer interface. The Asynchronous Line Monitoring feature feature available in Cisco IOS Release 12.2(4)T supports a PPP idle timer based on interesting traffic for dialer interfaces. (Existing PPP idle timer behavior is not changed when traffic is not classified.) New commands and functionality provided with this feature also address idle timer issues for virtual access dialup network (VPDN) sessions, which use virtual access (projected) interfaces and rely on the PPP idle timer mechanism.

The Resource Pool Manager (RPM) per-customer profile dialer idle timer function works with Multilink PPP (MLP) and Multichassis Multilink PPP (MMP), providing that the master bundle interface is not a virtual access (projected) interface. For virtual access interfaces such as those used in a VPDN or with MMP where the dialer idle timer cannot be used, you can now classify the IP traffic that resets the PPP idle timer. A named access list is also supported.

Additionally, because RPM customer profiles are applied on a per-Dialed Number Identification Service (DNIS) basis and allow for configuring a per-customer profile dialer idle timer, the Asynchronous Line Monitoring feature feature associates idle timers based on call type and DNIS.

The idle timer implementation in the Asynchronous Line Monitoring feature feature specifies that for calls terminated on a network access server, a virtual access interface is cloned from the virtual template. This virtual access interface is linked to a physical interface on which is running a dialer timer. If the PPP idle timer is configured on the virtual template or provided by an authentication, authorization, and accounting (AAA) per-user interface configuration, the result is two idle timers, as follows:

- A PPP idle timer on the virtual access interface.

- A dialer idle timer on the physical interface.

Neither the dialer idle timer nor the PPP idle timer will run when the idle timer in the per-user configuration is set to 0. When the per-user idle timer is set to some value besides 0, that value overrides all local idle timer configurations.

Benefits

The Asynchronous Line Monitoring feature feature provides the following system idle timer benefits:

- Resets the PPP idle timer based on interesting inbound or outbound IP traffic for virtual access interfaces on Layer 2 Tunnel Protocol (L2TP) access concentrators (LACs) and L2TP network servers (LNSs).

- Associates the dialer timer with interesting traffic within RPM customer profiles.

- Applies the user idle-timer value RADIUS attribute 28 across all interfaces associated with the call.

Restrictions

The PPP idle timer can classify IP traffic only.

Supported Platforms

See the next section for information about Feature Navigator and how to use this tool to determine the platforms and software images in which this feature is available.

Platform Support Through Feature Navigator

Cisco IOS software is packaged in feature sets that support specific platforms. To get updated information regarding platform support for this feature, access Feature Navigator. Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.

Feature Navigator is a web-based tool that enables you to quickly determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image.

To access Feature Navigator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions at http://www.cisco.com/register.

Feature Navigator is updated when major Cisco IOS software releases and technology releases occur. As of May 2001, Feature Navigator supports M, T, E, S, and ST releases. You can access Feature Navigator at the following URL:

http://www.cisco.com/go/fn

Supported Standards, MIBs, and RFCs

Standards

None

MIBs

None

To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

RFCs

None

Configuration Tasks

See the following sections for configuration tasks for the Asynchronous Line Monitoring feature feature. Each task in the list is identified as either required or optional:

- Configuring an RPM Template to Accept Dialer Interface Timers (required)

- Configuring a PPP Idle Timer Based on Interesting IP Traffic (required)

- Configuring the Idle Timer in a RADIUS Profile (optional)

- Verifying the Asynchronous Line Monitoring feature (optional)

Configuring an RPM Template to Accept Dialer Interface Timers

To configure a template to accept dialer interface timers, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# template name

Accesses the template configuration mode for configuring a particular customer profile template.

Step 2

Router(config-template)# dialer idle-timeout seconds

Sets the dialer idle timeout period in a virtual template interface.

Step 3

Router(config-template)# dialer-group dialer-list-number

Controls access by configuring an interface to belong to a specific dialing group.

Configuring a PPP Idle Timer Based on Interesting IP Traffic

To configure a PPP idle timer based on interesting IP traffic, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# interface virtual-template number

Creates a virtual template interface that can be configured and applied dynamically in creating virtual access interfaces, and enters interface configuration mode.

Step 2

Router(config-if)# ppp timeout idle time

Sets PPP idle timeout parameters on the virtual template interface.

Step 3

Router(config-if)# ip idle-group {access-list-number | access-list-name} {in | out}

Configures interesting inbound traffic (using the in keyword) or outbound traffic (using the out keyword) on a virtual template interface for the PPP idle timer.

See the configurations included in the “Configuration Examples” section for additional commands that you might configure.

Configuring the Idle Timer in a RADIUS Profile

To set the idle timer from AAA, configure the following RADIUS profile:

aaaa-idle Password = "password"

Service-Type = Framed,

Framed-Protocol = PPP,

Idle-timeout = 60

Verifying the Asynchronous Line Monitoring feature

To verify that the Asynchronous Line Monitoring feature is configured correctly, perform the following verification steps:

Step 1 To display the idle time configured, and any remote caller that is connected and its IP address, enter the show caller timeout EXEC command:

Router# show caller timeout

Line User Host(s) Idle Location

* 0 con 0 idle 00:00:00

47 tty 47 st-5300-c3 Async interface 00:00:15 PPP: 11.1.1.2

Interface User Mode Idle Peer Address

Step 2 Enter the show caller timeout EXEC command again. Notice that the show caller timeout command displays the idle timeout configured as 20 seconds:

Router# show caller timeout

Session Idle Disconnect

Line User Timeout Timeout User in

con 0 - - - -

tty 47 st-5300-c3 - 00:30:00 00:29:43

As47 st-5300-c3 - 00:00:20 now

Step 3 Continue entering the show caller timeout command. The displays show the timers counting down and then disconnecting.

Router# show caller timeout

Session Idle Disconnect

Line User Timeout Timeout User in

con 0 - - - -

tty 47 st-5300-c3 - 00:30:00 00:29:43

As47 st-5300-c3 - 00:00:20 now

Router#

Router# show caller timeout

Session Idle Disconnect

Line User Timeout Timeout User in

con 0 - - - -

tty 47 - - 00:30:00 00:29:41

Router# show caller timeout

Session Idle Disconnect

Line User Timeout Timeout User in

con 0 - - - -

tty 47 - - 00:30:00 00:29:38

Router# show caller timeout

Session Idle Disconnect

Line User Timeout Timeout User in

con 0 - - - -

Troubleshooting Tips

To troubleshoot the Asynchronous Line Monitoring feature feature, use the following debugging commands:

- debug cca

- debug aaa authen

- debug aaa author

- debug aaa per-user

- debug ppp authen

- debug ppp neg

- debug radius

- debug isdn q931

- debug dialer detail

- debug vaccess

- debug vprofile

Monitoring and Maintaining the Asynchronous Line Monitoring feature

To monitor and maintain the Asynchronous Line Monitoring feature feature, use the following EXEC commands:

Command

Purpose

Router# show caller

Displays caller information.

Router# show ip access-list

Displays the contents of all current IP access lists.

Router# show users

Displays information about the active lines on the router.

Configuration Examples

This section provides the following configuration examples:

- Two Templates with Different Dialer Idle Timer Settings Example

- Resetting the Dialer Idle Timer with Interesting Traffic Example

- Network Access Server Extended Configuration Example

Two Templates with Different Dialer Idle Timer Settings Example

The following partial example shows how to configure two customer profiles, each with different templates. Notice that each template sets the dialer idle timer differently:

resource-pool enable

!

resource-pool profile customer prf_cust_1

limit base-size all

limit overflow-size 0

dnis group dnis_g1

source template template1

!

resource-pool profile customer prf_cust_2

limit base-size all

limit overflow-size 0

dnis group dnis_g2

source template template2

!

template template1

dialer idle-timeout 45

dialer-group 1

!

template template2

dialer idle-timeout 90

dialer-group 2

!

dialer dnis group dnis_g1

number 11111111

!

dialer dnis group dnis_g2

number 22222222

Resetting the Dialer Idle Timer with Interesting Traffic Example

The following partial example shows how to configure an RPM customer profile that sets the dialer idle timer in a virtual template interface based on either inbound or outbound traffic:

resource-pool enable

!

resource-pool profile customer prf_cust_1

limit base-size all

limit overflow-size 0

dnis group dnis_g1

source template template1

!

template template1

dialer idle-timeout 45 either

dialer-group 1

!

dialer dnis group dnis_g1

number 1231231234

Network Access Server Extended Configuration Example

The following example shows the configuration for a Cisco AS5300 series access server, which is part of a large-scale dial-out configuration. Notice that on virtual template interface 1 the PPP idle timer is configured to reset only on interesting inbound traffic, and that both dialer interface idle timers are set to 60 seconds:

hostname 5300

!

aaa new-model

aaa authentication ppp default local group radius none

aaa authorization network default local group radius none

!

username 4500 password 0 cisco

username 5300 password 0 cisco

username 2500-1 password 0 cisco

username 2500-2 password 0 cisco

username LAC password 0 cisco

username LNS password 0 cisco

username SGBP password 0 cisco

spe 1/0 2/9

firmware location system:/ucode/mica_port_firmware

!

resource-pool enable

!

resource-pool group resource modem

range port 1/0 1/48

!

resource-pool group resource data

range limit 20

!

resource-pool profile customer cust

limit base-size all

limit overflow-size 0

resource modem speech

resource data digital

dnis group dnis_g7

source template1

!

dialer dnis group dnis_g7

number 11111112

ip subnet-zero

!

sgbp group MMP

sgbp member 2500-2 10.0.38.3

sgbp ppp-forward

!

vpdn enable

no vpdn logging

!

isdn switch-type primary-5ess

!

template template1

dialer idle-timeout 27

dialer-group 1

!

controller T1 0

framing esf

clock source line primary

linecode b8zs

pri-group timeslots 1-24

!

interface Loopback1

ip address 192.168.14.1 255.255.255.255

no ip route-cache

no ip mroute-cache

!

interface Ethernet0

ip address 10.0.38.14 255.255.255.0

no ip route-cache

no ip mroute-cache

!

interface Virtual-Template1

ip unnumbered Loopback1

peer default ip address pool local_pool

ppp authentication chap callin

ppp chap hostname name

ppp timeout idle 60

ip idle-group 101 in

ip idle-group 102 in

ppp multilink

!

interface Serial0:23

ip unnumbered Loopback1

encapsulation ppp

ip mroute-cache

load-interval 30

dialer load-threshold 1 outbound

dialer-group 2

isdn switch-type primary-5ess

isdn incoming-voice modem

ppp authentication chap callin

ppp multilink

!

interface Async1

ip unnumbered Loopback1

encapsulation ppp

dialer in-band

dialer rotary-group 1

dialer-group 1

async mode dedicated

!

interface Dialer1

ip unnumbered Loopback1

encapsulation ppp

dialer in-band

dialer idle-timeout 60

dialer-group 1

peer default ip address pool local_pool

ppp authentication chap callin

ppp chap hostname name

!

ip local pool local_pool 10.1.14.1 10.1.14.254

ip classless

ip route 172.0.0.0 255.0.0.0 Ethernet0

ip route 192.168.0.0 255.255.255.0 10.0.38.1

no ip http server

!

access-list 101 deny icmp any any

access-list 101 permit ip any any

!

access-list 102 deny tcp any any

access-list 102 permit ip any any

!

dialer-list 1 protocol ip list 101

dialer-list 2 protocol ip list 102

dialer-list 3 protocol ip permit

!

access-list 101 permit icmp any any

access-list 102 deny ip any any

radius-server host 172.69.70.72 auth-port 1645 acct-port 1646

radius-server retransmit 3

radius-server key cisco

!

line con 0

exec-timeout 0 0

transport input none

line 1 2

no exec

exec-timeout 0 0

autoselect ppp

script dialer dial

script reset reset

modem InOut

modem autoconfigure discovery

transport input all

line 2 240

no exec

exec-timeout 0 0

transport input all

line aux 0

line vty 0 4

!

end

Command Reference

The following commands are introduced or modified in the feature or features documented in this module. For information about these commands, see the Cisco IOS Dial Technologies Command Reference at http://www.cisco.com/en/US/docs/ios/dial/command/reference/dia_book.html. For information about all Cisco IOS commands, go to the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or to the Cisco IOS Master Commands List.

New Commands

- ip idle-group

- dialer-group (template)

- dialer idle-timeout (template)

- ppp timeout idle (template)

Modified Command

- dialer-list protocol

Glossary

interesting packets —Dialer access lists are central to the operation of DDR. In general, access lists are used as the screening criteria for determining when to initiate DDR calls.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

.Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2008–2009 Cisco Systems, Inc. All rights reserved.

Troubleshooting Enhancements for Multilink PPP over ATM Link Fragmentation and Interleaving

The Troubleshooting Enhancements for Multilink PPP over ATM Link Fragmentation and Interleaving enhance the output of the show atm pvc, show multilink ppp, and show interfaces virtual-access commands to display multilink PPP (MLP) over ATM link fragmentation and interleaving (LFI) information. This feature also introduces the debug atm lfi command, which can be used to display MLP over ATM LFI debugging information.

Feature History for Troubleshooting Enhancements for Multilink PPP over ATM LFI

Release

Modification

12.3(7)T

This feature was introduced.

Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

Contents

- How to Troubleshoot Multilink PPP over ATM LFI

- Additional References

- Command Reference

How to Troubleshoot Multilink PPP over ATM LFI

This section contains the following procedure:

- Troubleshooting Multilink PPP over ATM LFI

Troubleshooting Multilink PPP over ATM LFI

Perform this task to display information about multilink PPP over ATM LFI connections.

Prerequisites

This task assumes that you have configured multilink PPP over ATM LFI in your network. For information about how to configure multilink PPP over ATM LFI, see the “Additional References” section.

SUMMARY STEPS

1. enable

2. show atm pvc vpi/vci

3. show ppp multilink [active | inactive | interface bundle-interface | [username name] [endpoint endpoint]]

4. show interfaces virtual-access [type number]

5. debug atm lfi

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

show atm pvc vpi/vci

Router# show atm pvc 15/200

Displays traffic, management, and MLP over ATM LFI information for the specified PVC.

Step 3

show ppp multilink [active | inactive | interface bundle-interface | [username name] [endpoint endpoint]]

Router# show ppp multilink username blue

Displays bundle information for MLP bundles.

Step 4

show interfaces virtual-access number

Router# show interfaces virtual-access 3

Displays status, traffic data, and configuration information about a specified virtual access interface.

- Display will indicate if the interface is a member of a multilink PPP bundle.

Step 5

debug atm lfi

Router# debug atm lfi

Displays MLP over ATM LFI debug information.

Examples

See the show atm pvc, show ppp multilink, show interfaces virtual-access, and debug atm lfi command pages for examples of output and descriptions of the fields in the output. For information about where to find the command pages for these commands, see Command Reference.

Additional References

The following sections provide references related to multilink PPP over ATM LFI.

Related Documents

Related Topic

Document Title

LFI for multilink PPP configuration tasks

“Configuring Link Fragmentation and Interleaving for Multilink PPP” chapter in the Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.2

LFI for ATM virtual circuits configuration tasks

“Configuring Link Fragmentation and Interleaving for Frame Relay and ATM Virtual Circuits” chapter in the Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.2

Multilink PPP over ATM LFI commands

Cisco IOS Quality of Service Solutions Command Reference, Release 12.3 T

Multilink PPP configuration tasks

“PPP Configuration” section in the Cisco IOS Dial Technologies Configuration Guide, Release 12.3

Multilink PPP commands

Cisco IOS Dial Technologies Command Reference, Release 12.3 T

ATM configuration tasks

“WAN Protocols” section in the Cisco IOS Wide-Area Networking Configuration Guide, Release 12.3

ATM commands

Cisco IOS Wide-Area Networking Command Reference, Release 12.3 T

MIBs

MIBs

MIBs Link

No new or modified MIBs are supported by this feature.

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

Technical Assistance

Description

Link

Technical Assistance Center (TAC) home page, containing 30,000 pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

http://www.cisco.com/public/support/tac/home.shtml

Command Reference

- debug atm lfi

- show atm pvc

- show interfaces virtual-access

- show ppp multilink

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2001–2009 Cisco Systems, Inc. All rights reserved.

Configuring PPP Callback

This chapter describes how to configure PPP callback for dial-on-demand routing (DDR). It includes the following main sections:

- PPP Callback for DDR Overview

- How to Configure PPP Callback for DDR

- MS Callback Overview

- How to Configure MS Callback

- Configuration Examples for PPP Callback

This feature implements the following callback specifications of RFC 1570:

- For the client—Option 0, location is determined by user authentication.

- For the server—Option 0, location is determined by user authentication; Option 1, dialing string; and Option 3, E.164 number.

Return calls are made through the same dialer rotary group but not necessarily the same line as the initial call.

To identify the hardware platform or software image information associated with a feature, use the Feature Navigator on Cisco.com to search for information about the feature or refer to the software release notes for a specific release. For more information, see the “Identifying Supported Platforms” section in the “Using Cisco IOS Software” chapter.

For a complete description of the PPP callback commands mentioned in this chapter, refer to the Cisco IOS Dial Technologies Command Reference. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

PPP Callback for DDR Overview

PPP callback provides a client/server relationship between the endpoints of a point-to-point connection. PPP callback allows a router to request that a dialup peer router call back. The callback feature can be used to control access and toll costs between the routers.

When PPP callback is configured on the participating routers, the calling router (the callback client) passes authentication information to the remote router (the callback server), which uses the host name and dial string authentication information to determine whether to place a return call. If the authentication is successful, the callback server disconnects and then places a return call. The remote username of the return call is used to associate it with the initial call so that packets can be sent.

Both routers on a point-to-point link must be configured for PPP callback; one must function as a callback client and one must be configured as a callback server. The callback client must be configured to initiate PPP callback requests, and the callback server must be configured to accept PPP callback requests and place return calls.

See the section “MS Callback Overview” later in this chapter if you are using PPP callback between a Cisco router or access server and client devices configured for Windows 95 and Windows NT.

Note If the return call fails (because the line is not answered or the line is busy), no retry occurs. If the callback server has no interface available when attempting the return call, it does not retry.

How to Configure PPP Callback for DDR

To configure PPP callback for DDR, perform the following tasks:

- Configuring a Router As a Callback Client (Required)

- Configuring a Router As a Callback Server (Required)

For an example of configuring PPP callback, see the section “Configuration Examples for PPP Callback” at the end of this chapter.

Configuring a Router As a Callback Client

Command

Purpose

Step 1

Router(config)# interface type number

Specifies the interface and enters interface configuration mode.

Step 2

Router(config-if)# dialer in-band [no-parity | odd-parity]

Enables DDR. Specifies parity, if needed, on synchronous or asynchronous serial interfaces.

Step 3

Router(config-if)# encapsulation ppp

Enables PPP encapsulation.

Step 4

Router(config-if)# ppp authentication {chap | pap}

Enables CHAP or PAP authentication.

Step 5

Router(config-if)# dialer map protocol next-hop-address name hostname dial-string

Maps the next hop address to the host name and phone number.

Step 6

Router(config-if)# ppp callback request

Enables the interface to request PPP callback for this callback map class.

Step 7

Router(config-if)# dialer hold-queue packets timeout seconds

(Optional) Configures a dialer hold queue to store packets for this callback map class.

Configuring a Router As a Callback Server

To configure a router as a callback server, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# interface type number

Specifies the interface and enters interface configuration mode.

Step 2

Router(config-if)# dialer in-band [no-parity | odd-parity]

Enables DDR. Specifies parity, if needed, on synchronous or asynchronous serial interfaces.

Step 3

Router(config-if)# encapsulation ppp

Enables PPP encapsulation.

Step 4

Router(config-if)# ppp authentication {chap | pap}

Enables CHAP or PAP authentication.

Step 5

Router(config-if)# dialer map protocol next-hop-address name hostname class classname dial-string

Maps the next hop address to the host name and phone number, using the name of the map class established for PPP callback on this interface.

Step 6

Router(config-if)# dialer hold-queue number timeout seconds

(Optional) Configures a dialer hold queue to store packets to be transferred when the callback connection is established.

Step 7

Router(config-if)# dialer enable-timeout seconds

(Optional) Configures a timeout period between calls.

Step 8

Router(config-if)# ppp callback accept

Configures the interface to accept PPP callback.

Step 9

Router(config-if)# isdn fast-rollover-delay seconds

(ISDN only) Configures the time to wait before another call is placed on a B channel to allow the prior call to be torn down completely.

Step 10

Router(config-if)# dialer callback-secure

(Optional) Enables callback security, if desired.

Step 11

Router(config-if)# exit

Returns to global configuration mode.

Step 12

Router(config-map-class)# map-class dialer classname

Configures a dialer map class for PPP callback.

Step 13

Router(config-map-class)# dialer callback-server [username]

Configures a dialer map class as a callback server.

Note On the PPP callback server, the dialer enable-timeout command functions as the timer for returning calls to the callback client.

MS Callback Overview

MS Callback provides client/server callback services for Microsoft Windows 95 and Microsoft Windows NT clients. MS Callback supports the Microsoft Callback Control Protocol (MSCB). MSCB is a Microsoft proprietary protocol that is used by Windows 95 and Windows NT clients. MS Callback supports negotiated PPP Link Control Protocol (LCP) extensions initiated and agreed upon by the Microsoft client. The MS Callback feature is added to existing PPP Callback functionality. Therefore, if you configure your Cisco access server to perform PPP Callback using Cisco IOS Release 11.3(2)T or later, MS Callback is automatically available.

MS Callback supports authentication, authorization, and accounting (AAA) security models using a local database or AAA server.

MSCB uses LCP callback options with suboption type 6. The Cisco MS Callback feature supports clients with a user-specified callback number and server specified (preconfigured) callback number.

MS Callback does not affect non-Microsoft machines that implement standard PPP LCP extensions as described in RFC 1570. In this scenario, MS Callback is transparent.

The following are restrictions of the MS Callback feature:

- The Cisco access server and client must be configured for PPP and PPP callback.

- The router or access server must be configured to use CHAP or PAP authorization.

- MS Callback is only supported on the Public Switched Telephone Network (PSTN) and ISDN links.

- MS Callback is only supported for IP.

How to Configure MS Callback

If you configure the Cisco access server for PPP callback, MS Callback is enabled by default. You need not configure additional parameters on the Cisco access server. To debug PPP connections using MS Callback, see the debug ppp cbcp command in the Cisco IOS Debug Command Reference publication.

Configuration Examples for PPP Callback

The following example configures a PPP callback server and client to call each other. The PPP callback server is configured on an ISDN BRI interface in a router in Atlanta. The callback server requires an enable timeout and a map class to be defined. The PPP callback client is configured on an ISDN BRI interface in a router in Dallas. The callback client does not require an enable timeout and a map class to be defined.

PPP Callback Server

interface bri 0

ip address 10.1.1.7 255.255.255.0

encapsulation ppp

dialer callback-secure

dialer enable-timeout 2

dialer map ip 10.1.1.8 name atlanta class dial1 81012345678901

dialer-group 1

ppp callback accept

ppp authentication chap

!

map-class dialer dial1

dialer callback-server username

PPP Callback Client

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2007-2008 Cisco Systems, Inc. All rights reserved.

Configuring ISDN Caller ID Callback

This chapter describes how to configure the ISDN Caller ID Callback feature. It includes the following main sections:

- ISDN Caller ID Callback Overview

- How to Configure ISDN Caller ID Callback

- Monitoring and Troubleshooting ISDN Caller ID Callback

- Configuration Examples for ISDN Caller ID Callback

The ISDN Caller ID Callback feature conflicts with dialer callback security inherent in the dialer profiles feature for dial-on-demand routing (DDR). If dialer callback security is configured, it takes precedence; ISDN caller ID callback is ignored.

Caller ID screening requires a local switch that is capable of delivering the caller ID to the router or access server. If you enable caller ID screening but do not have such a switch, no calls will be allowed in.

ISDN caller ID callback requires DDR to be configured and bidirectional dialing to be working between the calling and callback routers. Detailed DDR prerequisites depend on whether you have configured legacy DDR or dialer profiles.

For a legacy DDR configuration, ISDN caller ID callback has the following prerequisite:

- A dialer map command is configured for the dial string that is used in the incoming call setup message. The dial string is used in the callback.

For a dialer profiles configuration, ISDN caller ID callback has the following prerequisites:

- A dialer caller command is configured to screen for the dial-in number.

- A dialer string command is configured with the number to use in the callback.

To identify the hardware platform or software image information associated with a feature, use the Feature Navigator on Cisco.com to search for information about the feature or refer to the software release notes for a specific release. For more information, see the “Identifying Supported Platforms” section in the “Using Cisco IOS Software” chapter.

For a complete description of the ISDN caller ID callback commands mentioned in this chapter, refer to the Cisco IOS Dial Technologies Command Reference, Release 12.2. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

ISDN Caller ID Callback Overview

ISDN caller ID callback allows the initial incoming call from the client to the server to be rejected on the basis of the caller ID message contained in the ISDN setup message, and it allows a callback to be initiated to the calling destination.

Before Cisco IOS Release 11.2 F, ISDN callback functionality required PPP or Combinet Packet Protocol (CPP) client authentication and client/server callback negotiation to proceed. If authentication and callback negotiation were successful, the callback server had to disconnect the call and then place a return call. Both the initial call and the return call were subject to tolls, and when service providers charge by the minute, even brief calls could be expensive.

This feature is independent of the encapsulation in effect and can be used with various encapsulations, such as PPP, High-Level Data Link Control (HDLC), Frame Relay, and X.25.

The ISDN Caller ID Callback feature allows users to control costs because charges do not apply to the initial, rejected call.

ISDN caller ID callback allows great flexibility for you to define which calls to accept, which to deny, and which calls to reject initially but for which the router should initiate callback. The feature works by using existing ISDN caller ID screening, which matches the number in the incoming call against numbers configured on the router, determining the best match for the number in the incoming call, and then, if configured, initiating callback to the number configured on the router.

When a call is received, the entire list of configured numbers is checked and the configuration of the best match number determines the action:

- If the incoming number is best matched by a number that is configured for callback, the incoming call is rejected and callback is initiated.

- If the incoming number is best matched by another entry in the list of configured numbers, the call is accepted.

- If the incoming number does not match any entry in the configured list, the call is rejected and no callback is started.

“Don’t care” characters are allowed in the caller ID screening configuration on the router and are used to determine the best match.

For more information and examples, see the “Best Match System Examples” section later in this document.

Callback After the Best Match Is Determined

The details of router activities after the router finds a best match with callback depend on the DDR feature that is configured. The ISDN Caller ID Callback feature works with the following DDR features:

- Legacy DDR

- Dialer Profiles

Legacy DDR

If legacy DDR is configured for the host or user that is identified in the incoming call message, the router performs the following actions:

1. Checks the table of configured numbers for caller ID callback.

2. Searches the dialer map entries for a number that “best matches” the incoming call string.

3. Waits for a configured length of time to expire.

4. Initiates callback to the number provided in the dialer map command.

Dialer Profiles

If the dialer profiles are configured for the host or user identified in the incoming call message, the router performs the following actions:

1. Searches through all the dialer pool members to match the incoming call number to a dialer caller number.

2. Initiates a callback to the dialer profile.

3. Waits for a configured length of time to expire.

4. Calls the number identified in the dialer string command associated with the dialer profile.

Timing and Coordinating Callback on Both Sides

When an incoming call arrives and the router finds a best match configured for callback, the router uses the value configured by the dialer enable-timeout command to determine the length of time to wait before making the callback.

The minimum value of the timer is 1 second; the default value of the timer is 15 seconds. The interval set for this feature on the router must be much less than that set for DDR fast call rerouting for ISDN (that interval is set by the dialer wait-for-carrier-time command) on the calling (remote) side. We recommend setting the dialer wait-for-carrier timer on the calling side to twice the length of the dialer enable-timeout timer on the callback side.

Note The remote site cannot be configured for multiple dial-in numbers because a busy callback number or a rejected call causes the second number to be tried. That number might be located at a different site, defeating the purpose of the callback.

How to Configure ISDN Caller ID Callback

To configure ISDN caller ID callback, perform the tasks in the following sections. The required configuration tasks depend whether you have configured legacy DDR or dialer profiles.

- Configuring ISDN Caller ID Callback for Legacy DDR (As required)

- Configuring ISDN Caller ID Callback for Dialer Profiles (As required)

For configuration examples, see the section “Configuration Examples for ISDN Caller ID Callback” at the end of this chapter.

Configuring ISDN Caller ID Callback for Legacy DDR

This section provides configuration tasks for the local (server, callback) side and the remote (client, calling) side.

On the callback (local) side, to configure ISDN caller ID callback when legacy DDR is configured, use the following commands in interface configuration mode:

Command

Purpose

Step 1

Router(config-if)# isdn caller remote-number callback

or

Router(config-if)# dialer caller number callback

Configures caller ID screening and callback when a dialer rotary (dialer interface) is configured.

Step 2

Router(config-if)# dialer enable-timeout seconds

Configures the time to wait before initiating callback.

On the calling (remote) side, to set the timer for fast call rerouting, use the following command in interface configuration mode:

Command

Purpose

Router(config-if)# dialer wait-for-carrier-time seconds

Changes the ISDN fast call rerouting timer to double the length of the enable timeout timer.

Configuring ISDN Caller ID Callback for Dialer Profiles

This section provides configuration tasks for the local side and the remote side.

Command

Purpose

Step 1

Router(config-if)# dialer caller number callback

Configures caller ID screening and callback.

Step 2

Router(config-if)# dialer enable-timeout seconds

Configures the time to wait before initiating callback.

On the calling (remote) side, to set the timer for fast call rerouting, use the following command in interface configuration mode:

Command

Purpose

Router(config-if)# dialer wait-for-carrier-time seconds

Changes the ISDN fast call rerouting timer to double the length of the enable timeout timer.

Monitoring and Troubleshooting ISDN Caller ID Callback

To monitor and troubleshoot ISDN caller ID callback, use the following commands in EXEC mode as needed:

Command

Purpose

Router# show dialer

Displays information about the status and configuration of the ISDN interface on the router.

Router# debug isdn event

Displays ISDN events occurring on the user side (on the router) of the ISDN interface. The ISDN events that can be displayed are Q.931 events (call setup and tear down of ISDN network connections).

Router# debug isdn q931

Displays Layer 3 signaling messages, protocol transitions and processes, the line protocol state, and the channel IDs for each ISDN interface.

Configuration Examples for ISDN Caller ID Callback

The following sections provide ISDN caller ID callback configuration examples:

- Best Match System Examples

- Simple Callback Configuration Examples

- ISDN Caller ID Callback with Dialer Profiles Examples

- ISDN Caller ID Callback with Legacy DDR Example

Best Match System Examples

The best match is determined by matching the incoming number against the numbers in the configured callback commands, starting with the right-most character in the numbers and using the letter X for any “don’t care” characters in the configured commands. If multiple configured numbers match an incoming number, the best match is the one with the fewest “don’t care” characters.

The reason for using a system based on right-most matching is that a given number can be represented in many different ways. For example, all the following items might be used to represent the same number, depending on the circumstances (international call, long-distance domestic call, call through a PBX, and so forth):

011 1 408 555 7654

1 408 555 7654

408 555 7654

555 7654

5 7654

Best Match Based on the Number of “Don’t Care” Characters Example

Note The last number in the list shown allows calls from any other number to be accepted without callback. When you use such a line, you must make sure that the number of Xs in the line exceeds the number of Xs in any other line. In the last line, five Xs are used; the other lines use at most four Xs.

The order of configured numbers is not important; the router searches the entire list and then determines the best match.

Best Match with No Callback Configured Example

No Match Configured Example

Simple Callback Configuration Examples

isdn caller 4155551234

The following example configures the router to accept a call with a delivered caller ID equal to 41555512 with any digits in the last two positions:

isdn caller 41555512xx

The following example configures the router to make a callback to a delivered caller ID equal to 41555512 with any digits in the last two positions. (The router rejects the call initially, and then makes the callback.) The router accepts calls from any other numbers.

isdn caller 41555512xx callback

isdn caller xxx

ISDN Caller ID Callback with Dialer Profiles Examples

The following example shows the configuration of a central site that can place or receive calls from three remote sites over four ISDN BRI lines. Each remote site is on a different IP subnet and has different bandwidth requirements. Therefore, three dialer interfaces and three dialer pools are defined.

! This is a dialer profile for reaching remote subnetwork 10.1.1.1.

interface dialer 1

ip address 10.1.1.1 255.255.255.0

encapsulation ppp

dialer remote-name Smalluser

dialer string 4540

dialer pool 3

dialer-group 1

dialer caller 14802616900 callback

dialer caller 1480262xxxx callback

!

! This is a dialer profile for reaching remote subnetwork 10.2.2.2.

interface dialer 2

ip address 10.2.2.2 255.255.255.0

encapsulation ppp

dialer remote-name Mediumuser

dialer string 5264540 class Eng

dialer load-threshold 50 either

dialer pool 1

dialer-group 2

dialer caller 14805364540 callback

dialer caller 1480267xxxx callback

dialer enable-timeout 2

!

! This is a dialer profile for reaching remote subnetwork 10.3.3.3.

interface dialer 3

ip address 10.3.3.3 255.255.255.0

encapsulation ppp

dialer remote-name Poweruser

dialer string 4156884540 class Eng

dialer hold-queue 10

dialer load-threshold 80

dialer pool 2

dialer-group 2

!

! This map class ensures that these calls use an ISDN speed of 56 kbps.

map-class dialer Eng

isdn speed 56

!

interface bri 0

encapsulation PPP

! BRI 0 has a higher priority than BRI 1 in dialer pool 1.

dialer pool-member 1 priority 100

ppp authentication chap

!

interface bri 1

encapsulation ppp

dialer pool-member 1 priority 50

dialer pool-member 2 priority 50

! BRI 1 has a reserved channel in dialer pool 3; the channel remains inactive

! until BRI 1 uses it to place calls.

dialer pool-member 3 min-link 1

ppp authentication chap

!

interface bri 2

encapsulation ppp

! BRI 2 has a higher priority than BRI 1 in dialer pool 2.

dialer pool-member 2 priority 100

ppp authentication chap

!

interface bri 3

encapsulation ppp

! BRI 3 has the highest priority in dialer pool 2.

dialer pool-member 2 priority 150

ppp authentication chap

ISDN Caller ID Callback with Legacy DDR Example

This section provides two examples of caller ID callback with legacy DDR:

- Individual Interface Example

- Dialer Rotary Group Example

Individual Interface Example

The following example configures a BRI interface for legacy DDR and ISDN caller ID callback:

interface bri 0

description Connected to NTT 81012345678901

ip address 10.1.1.7 255.255.255.0

no ip mroute-cache

encapsulation ppp

isdn caller 81012345678902 callback

dialer enable-timeout 2

dialer map ip 10.1.1.8 name spanky 81012345678902

dialer-group 1

ppp authentication chap

Dialer Rotary Group Example

The following example configures BRI interfaces to connect into a rotary group (dialer group) and then configures a dialer interface for that dialer group. This configuration permits IP packets to trigger calls. The dialer interface is configured to initiate callback to any number in the 1-480-261 exchange and to accept calls from two other specific numbers.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2007–2009 Cisco Systems, Inc. All rights reserved.

Configuring BACP

This chapter describes how to configure the Bandwidth Allocation Control Protocol (BACP), described in RFC 2125. It includes the following main sections:

- BACP Overview

- How to Configure BACP

- Monitoring and Maintaining Interfaces Configured for BACP

- Troubleshooting BACP

- Configuration Examples for BACP

BACP requires a system only to have the knowledge of its own phone numbers and link types. A system must be able to provide the phone numbers and link type to its peer to satisfy the call control mechanism. (Certain situations might not be able to satisfy this requirement; numbers might not be present because of security considerations.)

BACP is designed to operate in both the virtual interface environment and the dialer interface environment. It can operate over any physical interface that is Multilink PPP-capable and has a dial capability; at initial release, BACP supports ISDN and asynchronous serial interfaces.

The addition of any link to an existing multilink bundle is controlled by a Bandwidth Allocation Protocol (BAP) call or callback request message, and the removal of a link can be controlled by a link drop message.

To identify the hardware platform or software image information associated with a feature, use the Feature Navigator on Cisco.com to search for information about the feature or refer to the software release notes for a specific release. For more information, see the “Identifying Supported Platforms” section in the “Using Cisco IOS Software” chapter.

For a complete description of the PPP BACP commands in this chapter, refer to the Cisco IOS Dial Technologies Command Reference, Release 12.2. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

BACP Overview

The BACP provides Multilink PPP (MLP) peers with the ability to govern link utilization. Once peers have successfully negotiated BACP, they can use the BAP, which is a subset of BACP, to negotiate bandwidth allocation. BAP provides a set of rules governing dynamic bandwidth allocation through call control; a defined method for adding and removing links from a multilink bundle for Multilink PPP is used.

BACP provides the following benefits:

- Allows multilink implementations to interoperate by providing call control through the use of link types, speeds, and telephone numbers.

- Controls thrashing caused by links being brought up and removed in a short period of time.

- Ensures that both ends of the link are informed when links are added or removed from a multilink bundle.

For simplicity, the remaining text of this chapter makes no distinction between BACP and BAP; only BACP is mentioned.

BACP Configuration Options

PPP BACP can be configured to operate in the following ways:

- Passive mode (default)—The system accepts incoming calls; the calls might request callback, addition of a link, or removal of a link from a multilink bundle. The system also monitors the multilink load by default.

Passive mode is for virtual template interfaces or for dialer interfaces.

- Active mode—The system initiates outbound calls, sets the parameters for outbound calls, and determines whether links should be added to or removed from a multilink bundle. The system also monitors the multilink load by default.

Active mode is for dialer interfaces, but not for virtual template interfaces. (If you attempt to configure active mode on a virtual template interface, no calls will be made.)

A virtual or dialer interface must be configured either to make call requests or to make callback requests, but it cannot be configured to do both.

Support of BACP on virtual interfaces in an Multichassis Multilink PPP (MMP) environment is restricted to incoming calls on the multilink group. Support of BACP for outgoing calls is provided by dialer interface configuration only.

BACP supports only ISDN and asynchronous serial interfaces.

Dialer support is provided only for legacy dial-on-demand routing (DDR) dialer configurations; BACP cannot be used in conjunction with the DDR dialer profiles feature.

BACP is configured on virtual template interfaces and physical interfaces that are multilink capable. For both the virtual template interfaces and the dialer interfaces, BACP requires MMP and bidirectional dialing to be working between the routers that will negotiate control and allocation of bandwidth for the multilink bundle.

How to Configure BACP

Before you configure BACP on an interface, determine the following important information. The router might be unable to connect to a peer if this information is incorrect.

- Type of link (ISDN or analog) to be used. Link types must match on the local and remote ends of the link.

- Line speed needed to reach the remote peer. The speed configured for the local physical interface must be at least that of the link. The bandwidth command or the dialer map command with the speed keyword can be used.

- Local telephone number to be used for incoming PPP BACP calls, if it is different from a rotary group base number or if incoming PPP BACP calls should be directed to a specific number.

During negotiations with a peer, PPP BACP might respond with a telephone number delta, indicating that the peer should modify certain digits of the dialed phone number and dial again to reach the PPP BACP interface or to set up another link.

BACP can be configured on a virtual template interface or on a dialer interface (including dialer rotary groups and ISDN interfaces).

To configure BACP on a selected interface or interface template, perform the following tasks in the order listed:

- Enabling BACP (Required)

Passive mode is in effect and the values of several parameters are set by default when PPP BACP is enabled. If you can accept all the passive mode parameters, do not continue with the tasks.

- Modifying BACP Passive Mode Default Settings (As required)

or

- Configuring Active Mode BACP (As required)

Note You can configure one interface in passive mode and another in active mode so that one interface accepts incoming call requests and makes callback requests (passive mode), and the other interface makes call requests and accepts callback requests (active mode).

A dialer or virtual template interface should be configured to reflect the required dial capability of the interface. A dial-in pool (in passive mode) might have no requirement to dial out but might want remote users to add multiple links, with the remote user incurring the cost of the call. Similarly, a dial-out configuration (active mode) suggests that the router is a client, rather than a server, on that link. The active-mode user incurs the cost of additional links.

You might need to configure a base telephone number, if it is applicable to your dial-in environment. This number is one that remote users can dial to establish a connection. Otherwise, individual PPP BACP links might need numbers. Information is provided in the task lists for configuring passive mode or active mode PPP BACP. See the ppp bap number command options in the task lists.

You can also troubleshoot BACP configuration and operations and monitor interfaces configured for PPP BACP. For details, see the “Troubleshooting BACP” and “Monitoring and Maintaining Interfaces Configured for BACP” sections later in this chapter.

See the section “Configuration Examples for BACP” at the end of this chapter for examples of PPP BACP configuration.

Enabling BACP

To enable PPP bandwidth allocation control and dynamic allocation of bandwidth, use one of the following commands in interface configuration mode:

Command

Purpose

Router(config-if)# ppp multilink bap

or

Router(config-if)# ppp multilink bap required

Enables PPP BACP bandwidth allocation negotiation and enforces mandatory negotiation of BACP for the multilink bundle.

When PPP BACP is enabled, it is in passive mode by default and the following settings are in effect:

- Allows a peer to initiate link addition.

- Allows a peer to initiate link removal.

- Requests that a peer initiate link addition.

- Waits 20 seconds before timing out on pending actions.

- Waits 3 seconds before timing out on not receiving a response from a peer.

- Makes only one attempt to call a number.

- Makes up to three retries for sending a request.

- Searches for and logs up to five free dialers.

- Makes three attempts to send a call status indication.

- Adds only ISDN links to a multilink bundle.

- Monitors load.

The default settings will be in effect in the environment for which the ppp multilink bap command is entered:

- Virtual template interface, if that is where the command is entered.

When the command is entered in a virtual template interface, configuration applies to any virtual access interface that is created dynamically under Multilink PPP, the application that defines the template.

- Dialer interface, if that is where the command is entered.

See the section “Basic BACP Configurations” at the end of this chapter for an example of how to configure BACP.

Modifying BACP Passive Mode Default Settings

To modify the default parameter values or to configure additional parameters in passive mode, use the following commands, as needed, in interface configuration mode for the interface or virtual template interface that is configured for PPP BACP:

Command

Purpose

Router(config-if)# ppp bap timeout pending seconds

Modifies the timeout on pending actions.

Router(config-if)# ppp bap timeout response seconds

Modifies the timeout on not receiving a response from a peer.

Router(config-if)# ppp bap max dial-attempts number

Modifies the number of attempts to call a number.

Router(config-if)# ppp bap max ind-retries number

Modifies the number of times to send a call status indication.

Router(config-if)# ppp bap max req-retries number

Modifies the number of retries of a particular request.

Router(config-if)# ppp bap max dialers number

Modifies the maximum number of free dialers logged.

Router(config-if)# ppp bap link types analog

Router(config-if)# ppp bap link types isdn analog

Allows both ISDN and analog links to be added.

Router(config-if)# ppp bap number default phone-number

For all DDR-capable interfaces in the group, specifies a primary telephone number for the peer to call for PPP BACP negotiation, if different from any base number defined on the dialer interface or virtual template interface.

Router(config-if)# ppp bap number secondary phone-number

For BRI interfaces on which a different number is provided for each B channel, specifies the secondary telephone number.

Router(config-if)# ppp bap drop timer seconds

Specifies a time to wait between outgoing link drop requests.

Router(config-if)# no ppp bap monitor load

Disables the default monitoring of load and the validation of peer requests against load thresholds.

See the section “Passive Mode Dialer Rotary Group Members with One Dial-In Number” later in this chapter for an example of how to configure passive mode parameters.

Configuring Active Mode BACP

Command

Purpose

Router(config-if)# ppp bap call request

Enables the interface to initiate the addition of links to the multilink bundle.

Router(config-if)# ppp bap callback accept

Enables the interface to initiate the addition of links upon peer request.

Router(config-if)# ppp bap drop after-retries

Enables the interface to drop a link without negotiation after receiving no response to retries to send a drop request.

Router(config-if)# ppp bap call timer seconds

Sets the time to wait between outgoing call requests.

Router(config-if)# ppp bap timeout pending seconds

Modifies the timeout on pending actions.

Router(config-if)# ppp bap timeout response seconds

Modifies the timeout on not receiving a response from a peer.

Router(config-if)# ppp bap max dial-attempts number

Modifies the number of attempts to call a number.

Router(config-if)# ppp bap max ind-retries number

Modifies the number of times to send a call status indication.

Router(config-if)# ppp bap max req-retries number

Modifies the number of retries of a particular request.

Router(config-if)# ppp bap max dialers number

Modifies the maximum number of free dialers logged.

Router(config-if)# ppp bap link types analog

or

Router(config-if)# ppp bap link types isdn analog

Router(config-if)# ppp bap number default phone-number

For all DDR-capable interfaces in the group, specifies a primary telephone number for the peer to call for PPP BACP negotiation, if different from any base number defined on the dialer interface or virtual template interface.

Router(config-if)# ppp bap number secondary phone-number

For BRI interfaces on which a different number is provided for each B channel, specifies the secondary telephone number.

When BACP is enabled, multiple dialer maps to one destination are not needed when they differ only by number. That is, once the initial call has been made to create the bundle, further dialing attempts are realized through the BACP phone number negotiation.

Outgoing calls are supported through the use of dialer maps. However, when an initial incoming call creates a dynamic dialer map, the router can dial out if the peer supplies a phone number. This capability is achieved by the dynamic creation of static dialer maps for BACP. These temporary dialer maps can be displayed by using the show dialer map command. These temporary dialer maps last only as long as the BACP group lasts and are removed when the BACP group or the associated map is removed.

Monitoring and Maintaining Interfaces Configured for BACP

To monitor interfaces configured for PPP BACP, use any of the following commands in EXEC mode:

Command

Purpose

Router> show ppp bap group [name]

Displays information about all PPP BACP multilink bundle groups or a specific, named multilink bundle group.

Router> show ppp bap queues

Displays information about the BACP queues.

Router> show ppp multilink

Displays information about the dialer interface, the multilink bundle, and the group members.

Router> show dialer

Displays BACP numbers dialed and the reasons for the calls.

Router> show dialer map

Displays configured dynamic and static dialer maps and dynamically created BACP temporary static dialer maps.

Troubleshooting BACP

To troubleshoot the BACP configuration and operation, use the following debug commands:

Command

Purpose

Router> debug ppp bap [error | event | negotiation]

Displays BACP errors, protocol actions, and negotiation events and transitions.

Router> debug ppp multilink events

Displays information about events affecting multilink bundles established for BACP.

Configuration Examples for BACP

The following sections provide BACP configuration examples:

- Basic BACP Configurations

- Dialer Rotary Group with Different Dial-In Numbers

- Passive Mode Dialer Rotary Group Members with One Dial-In Number

- PRI Interface with No Defined PPP BACP Number

- BRI Interface with No Defined BACP Number

Basic BACP Configurations

interface async 1

no ip address

encapsulation ppp

dialer rotary-group 1

ppp bap number default 5663456

!

! Set the bandwidth to suit the modem/line speed on the remote side.

interface bri 0

no ip address

bandwidth 38400

encapsulation ppp

dialer rotary-group 1

ppp bap number default 5663457

!

interface bri 1

no ip address

encapsulation ppp

dialer rotary-group 1

ppp bap number default 5663458

!

interface dialer1

ip unnumbered ethernet 0

encapsulation ppp

ppp multilink bap

ppp bap call accept

ppp bap link types isdn analog

dialer load threshold 30

ppp bap timeout pending 60

The following example configures a virtual template interface to use BACP in passive mode:

multilink virtual-template 1

!

interface virtual-template 1

ip unnumbered ethernet 0

encapsulation ppp

ppp multilink bap

ppp authentication chap callin

The bundle is created from any MMP-capable interface.

The following example creates a bundle on a BRI interface:

interface bri 0

no ip address

encapsulation ppp

ppp multilink

ppp bap number default 4000

ppp bap number secondary 4001

Dialer Rotary Group with Different Dial-In Numbers

The following example configures a dialer rotary group that has four members, each with a different number, and that accepts incoming dial attempts. The dialer interface does not have a base phone number; the interface used to establish the first link in the multilink bundle will provide the appropriate number from its configuration.

interface bri 0

no ip address

encapsulation ppp

dialer rotary-group 1

no fair-queue

no cdp enable

ppp bap number default 6666666

!

interface bri 1

no ip address

encapsulation ppp

dialer rotary-group 1

no fair-queue

no cdp enable

ppp bap number default 6666667

!

interface bri 2

no ip address

encapsulation ppp

dialer rotary-group 1

no fair-queue

no cdp enable

ppp bap number default 6666668

!

interface bri 3

no ip address

encapsulation ppp

dialer rotary-group 1

no fair-queue

no cdp enable

ppp bap number default 6666669

!

interface dialer 1

ip unnumbered Ethernet0

encapsulation ppp

dialer in-band

dialer idle-timeout 300

dialer-group 1

no fair-queue

no cdp enable

ppp authentication chap

ppp multilink bap

ppp bap call accept

ppp bap callback request

ppp bap timeout pending 20

ppp bap timeout response 2

ppp bap max dial-attempts 2

ppp bap monitor load

Passive Mode Dialer Rotary Group Members with One Dial-In Number

The following example, a dialer rotary group with two members each with the same number, accepts incoming dial attempts. The dialer interface has a base phone number because each of its member interfaces is in a hunt group and the same number can be used to access each individual interface.

interface bri 0

no ip address

encapsulation ppp

dialer rotary-group 1

no fair-queue

no cdp enable

!

interface bri 1

no ip address

encapsulation ppp

dialer rotary-group 1

no fair-queue

no cdp enable

!

interface dialer 1

ip unnumbered Ethernet0

encapsulation ppp

dialer in-band

dialer idle-timeout 300

dialer-group 1

no fair-queue

no cdp enable

ppp authentication chap

ppp multilink bap

ppp bap call accept

ppp bap callback request

ppp bap timeout pending 20

ppp bap timeout response 2

ppp bap max dial-attempts 2

ppp bap monitor load

ppp bap number default 6666666

PRI Interface with No Defined PPP BACP Number

In the following example, a PRI interface has no BACP number defined and accepts incoming dial attempts (passive mode). The PRI interface has no base phone number defined, so each attempt to add a link would result in a delta of zero being provided to the calling peer. To establish the bundle, the peer should then dial the same number as it originally used.

interface serial 0:23

ip unnumbered Ethernet0

encapsulation ppp

dialer in-band

dialer idle-timeout 300

dialer-group 1

no fair-queue

no cdp enable

ppp authentication chap

ppp multilink bap

ppp bap call accept

ppp bap callback request

ppp bap timeout pending 20

ppp bap timeout response 2

ppp bap max dial-attempts 2

ppp bap monitor load

BRI Interface with No Defined BACP Number

In the following example, the BRI interface has no base phone number defined. The number that it uses to establish the bundle is that from the dialer map, and all phone delta operations are applied to that number.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2001–2009 Cisco Systems, Inc. All rights reserved.

Large-Scale Dial-Out (LSDO) VRF Aware

Feature History

Release

Modification

12.2(8)T

This feature was introduced.

This document describes the LSDO VRF Aware feature in Cisco IOS Release 12.2(8)T and includes the following sections:

- Feature Overview

- Supported Platforms

- Supported Standards, MIBs, and RFCs

- Prerequisites

- Configuration Tasks

- Configuration Examples

- Command Reference

- Glossary

Feature Overview

Currently, the Cisco large-scale dial-out (LSDO) feature is not supported in a Multiprotocol Label Switching (MPLS) virtual private network (VPN), which means it does not support tunneling protocols and cannot take advantage of cost benefits inherent in an MPLS VPN. (See the sections “Benefits” and the “Related Documents” for more details on the benefits of MPLS VPN.) Beginning with Cisco IOS Release 12.2(8)T, large-scale dial-out will support the Layer 2 Tunnel Protocol (L2TP) in an MPLS VPN.

The basic operation of large-scale dial-out relies on per-user static routes stored in an authentication, authorization, and accounting (AAA) server, and redistributed static and redistributed connected routes to put better routes pointing to the same remote network or host on the alternate network access server (NAS).

A static route is manually configured on a NAS. If the static route that pointed to the next hop of the NAS has a name, that name with the -out suffix attached becomes the profile name.

When a packet arrives on a dialer interface where a static map is not configured, the dial string is retrieved from the AAA server. The query made to the AAA server is based on the destination IP address of the packet received.

When using L2TP VPN large-scale dial-out, overlapping IP addresses are often present in virtual routing and forwarding instances (VRFs), so that a unique key is needed to retrieve the correct route from the AAA server. With VPDN as a dial-out resource, a virtual access interface is created for maintaining each PPP session. Software prior to Cisco IOS Release 12.2(8)T did not update the VRF information on the virtual access interface; rather, this information was cloned from the dialer interface.

In the Cisco IOS Release 12.2(8)T software, the VRF table identifier is retrieved from the incoming packet and is mapped to the VRF name. This VRF name and the destination IP address are combined to make the unique key needed to retrieve the dial string and other user profile information from the AAA server. When response from the AAA server is received and the virtual access interface is created, the virtual access interface is updated with VRF information that was retrieved from the incoming packet. As with profile names on dialer interfaces, the IP address and VRF name combination with the -out suffix attached becomes the profile name for large-scale dial-out in MPLS VPN using L2TP.

Note Another way to build a unique key is to use the name of the IP route. In this situation, the key is made from the IP route name and VRF name combination with the -out suffix attached. Refer to the technical note listed in the “Related Documents” section for more information.

Benefits

Layer 2 Tunneling Technologies Trim Costs by Forwarding Calls over the Internet

Access VPNs use Layer 2 tunneling technologies to create a virtual point-to-point connection between users and the customer network. These tunneling technologies provide the same direct connectivity as the expensive Public Switched Telephone Network (PSTN) by using the Internet. Instead of connecting directly to the network by using the PSTN, access VPN users need only use the PSTN to connect to the Internet service provider (ISP) local point of presence (POP). The ISP then uses the Internet to forward users from the POP to the customer network. Forwarding a user call over the Internet provides cost savings for the customer.

The MPLS VPN Model Simplifies Network Routing Configuration

The MPLS VPN model simplifies network routing by allowing VPN services to be supported in service provider networks. An MPLS VPN user can generally employ the backbone of the service provider as the default route in communicating with all of the other VPN sites.

The customer outsources the responsibility for the information technology (IT) infrastructure to an ISP that maintains the pool of modems the remote users dial in to, the access servers, and the internetworking expertise. The customer is responsible only for authenticating its users and maintaining its network.

L2TP Large-Scale Dial-Out Benefits from MPLS VPN Environment

The unique key created from the VRF name and the destination IP address allows retrieval of the dial string and other user profile information from a AAA server using L2TP in an MPLS VPN environment.

Restrictions

Cisco IOS Release 12.2(8)T supports only L2TP large-scale dial-out, and this feature makes it possible to retrieve only the dialer string that large-scale dial-out needs to construct the dynamic dialer map. This feature cannot create virtual access interfaces in the large-scale dial-out environment.

Related Documents

Additional information about configuring networks that can take advantage of this feature can be found in the following Cisco IOS documentation:

- Cisco IOS Dial Technologies Command Reference , Release 12.2.

- Cisco IOS Dial Technologies Configuration Guide , Release 12.2. Refer to the chapter “Configuring Large-Scale Dial-Out” in the part “Dial Access Specialized Features,” and the chapter “Configuring Virtual Private Networks” in the part “Virtual Templates, Profiles, and Networks.”

- Cisco IOS Switching Services Command Reference , Release 12.2.

- Cisco IOS Switching Services Configuration Guide , Release 12.2. Refer to the chapter “Multiprotocol Label Switching Overview” in the part “Multiprotocol Label Switching.”

Supported Platforms

Use Cisco’s Feature Navigator tool to determine which platforms support the Asynchronous Line Monitoring feature feature.

Determining Platform Support Through Feature Navigator

Cisco IOS software is packaged in feature sets that support specific platforms. To get updated information regarding platform support for this feature, access Feature Navigator. Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.

Feature Navigator is a web-based tool that enables you to quickly determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image.

To access Feature Navigator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions at http://www.cisco.com/register.

Feature Navigator is updated regularly when major Cisco IOS software releases and technology releases occur. For the most current information, go to the Feature Navigator home page at the following URL:

http://www.cisco.com/go/fn

Supported Standards, MIBs, and RFCs

Standards

None

MIBs

None

To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

RFCs

None

Prerequisites

No new Cisco IOS commands are introduced with the Asynchronous Line Monitoring feature feature. Before configuring this feature, read through the chapters listed in the “Related Documents” section, to be sure you know how to configure VPDNs, dialer interfaces, and MPLS, then use the examples in the section “Configuration Examples” to help you determine the configuration you need for your network.

Configuration Tasks

No new configuration tasks are required for configuring the Asynchronous Line Monitoring feature feature. See the sections “Prerequisites” and “Related Documents” for more information.

Monitoring and Maintaining Asynchronous Line Monitoring feature

Note Effective with Cisco Release 12.4(11)T, the L2F protocol was removed in Cisco IOS software.

Command

Purpose

Router# show dialer

Displays general diagnostic information for interfaces configured for DDR.

Router# show ip protocols vrf

Displays the routing protocol information associated with a VRF.

Router# show ip route vrf

Displays the IP routing table associated with a VPN routing and VRF forwarding instance.

Router# show ip vrf

Displays the set of defined VRF instances and associated interfaces.

Router# show vpdn

Displays information about active L2F protocol tunnel and L2F message identifiers in a VPDN.

Router# show vpdn domain

Displays all VPDN domains and DNIS groups configured on the NAS.

Router# show vpdn group

Displays a summary of the relationships among VPDN groups and customer or VPDN profiles, and summarizes the configuration of a VPDN group including domain or DNIS, loadsharing information, and current session information.

Router# show vpdn history failure

Displays the content of the failure history table.

Router# show vpdn multilink

Displays the multilink sessions authorized for all VPDN groups.

Router# show vpdn session

Displays information about active L2TP or L2F sessions in a VPDN.

Router# show vpdn tunnel

Displays information about active L2TP or L2F tunnels in a VPDN.

Configuration Examples

This section contains partial sample configurations of the Asynchronous Line Monitoring feature feature. (Additional examples can be found in the technical note listed in the “Related Documents” section.)

In the following examples, VRF VPN_A has two hosts with the IP address 1.1.1.1 and 2.2.2.2 and, similarly, VRF VPN_B has two hosts with IP address 1.1.1.1 and 2.2.2.2. The AAA server is configured with a list containing “10.10.10.10-VPN_A-out” and “10.10.10.10-VPN_B-out” as keys to search on.

Note The network addresses used in the following configuration are examples only and will not work if tried in an actual network configuration.

LNS Configuration

This partial example configures L2TP dial-out tunnels to an L2TP access concentrator (LAC) from an L2TP network server (LNS):

request-dialout

protocol l2tp

rotary-group 1

! LAC IP address:

initiate-to ip 172.16.0.2

local name PE2_LNS

l2tp tunnel password 7 13!9@61&

Dialer Configuration

This partial example configures the dialer interface:

interface Dialer 1

! Global IP address:

ip address 10.10.10.10

encapsulation ppp

dialer in-band

dialer aaa

dialer vpdn

dialer-group 1

ppp authentication chap

Routing Configuration

This partial example configures the VRF static routes:

ip route vrf VPN_A 1.1.1.1 255.255.255.255 Dialer1

ip route vrf VPN_A 2.2.2.2 255.255.255.255 Dialer1

ip route vrf VPN_B 1.1.1.1 255.255.255.255 Dialer1

ip route vrf VPN_B 2.2.2.2 255.255.255.255 Dialer1

Command Reference

This feature uses no new or modified commands. For information about all Cisco IOS commands, go to the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or to the Cisco IOS Master Commands List.

Glossary

L2TP—Layer 2 Tunnel Protocol. A tunneling protocol that permits separating the remote access network function—terminating the PSTN circuit, for example—from the local network access operations such as authenticating and authorizing the remote user.

L2TP access concentrator—See LAC.

L2TP network server—See LNS.

LAC—L2TP access concentrator. A node that acts as one side of an L2TP tunnel endpoint and is a peer to the LNS. The LAC sits between an LNS and a remote system and forwards packets to and from each. Packets sent from the LAC to the LNS require tunneling with the L2TP protocol. The connection from the LAC to the remote system is either local or a PPP link.

Layer 2 Tunnel Protocol—See L2TP.

LNS—L2TP network server. A device that terminates an L2TP tunnel. It receives the remote user PPP connection over an L2TP tunnel. The LNS authenticates and authorizes the remote user and then forwards packets between the remote user and the data network.

MPLS—Multiprotocol Label Switching. Switching method that forwards IP traffic using a label. This label instructs the routers and the switches in the network where to forward the packets based on pre-established IP routing information.

Multiprotocol Label Switching—See MPLS.

NAS—network access server. A device that provides local network access to users across a remote access network such as the PSTN. For example, a NAS may provide access to a user dialing in from the PSTN to the data network, that is, it terminates the PSTN circuit, terminates the remote user PPP session, authenticates and authorizes the remote user, and finally forwards packets between the remote user and the data network.

network access server—See NAS.

virtual private dialup network—See VPDN.

virtual routing and forwarding instance—See VRF.

VPDN—virtual private dialup network. A type of access VPN that uses PPP to interface with the subscriber. VPDN enables the service provider to configure VPNs across an IP access network that connects to the VRFs on a PE. VPDN uses the Layer 2 Tunnel Protocol (L2TP) to extend or "tunnel" a PPP session across the IP access network.

VRF—virtual routing and forwarding instance. Identifies a separate VPN within a particular MPLS VPN network domain.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2007-2008 Cisco Systems, Inc. All rights reserved.

Configuring Asynchronous Serial Traffic

over UDP

This chapter describes how to communicate with a modem using the Asynchronous Serial Traffic over UDP feature in the following main sections:

- UDPTN Overview

- Asynchronous Serial Traffic over UDP Configuration Task List

See the “UDPTN Configuration Examples” section for configuration examples.

To identify the hardware platform or software image information associated with a feature, use the Feature Navigator on Cisco.com to search for information about the feature or refer to the software release notes for a specific release. For more information, see the “Identifying Supported Platforms” section in the “Using Cisco IOS Software” chapter.

For a complete description of the UDP commands mentioned in this chapter, refer to the Cisco IOS Dial Technologies Command Reference, Release 12.2. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

UDPTN Overview

The Asynchronous Serial Traffic over UDP feature provides the ability to encapsulate asynchronous data into User Datagram Protocol (UDP) packets and then unreliably send this data without needing to establish a connection with a receiving device. This process is referred to as UDP Telnet (UDPTN), although it does not—and cannot—use the Telnet protocol. UDPTN is similar to Telnet in that both are used to send data, but UDPTN is unique in that it does not require that a connection be established with a receiving device. You load the data that you want to send through an asynchronous port, and then send it, optionally, as a multicast or a broadcast. The receiving device(s) can then receive the data whenever it wants. If the receiver ends reception, the transmission is unaffected.

The Asynchronous Serial Traffic over UDP feature provides a low-bandwidth, low-maintenance method to unreliably deliver data. This delivery is similar to a radio broadcast: It does not require that you establish a connection to a destination; rather, it sends the data to whatever device wants to receive it. The receivers are free to begin or end their reception without interrupting the transmission.

It is a low-bandwidth solution for delivering streaming information for which lost packets are not critical. Such applications include stock quotes, news wires, console monitoring, and multiuser chat features.

This feature is particularly useful for broadcast, multicast, and unstable point-to-point connections. This feature may not work as expected when there are multiple users on the same port number in a nonmulticast environment. The same port must be used for both receiving and sending.

Asynchronous Serial Traffic over UDP Configuration Task List

To configure the Asynchronous Serial Traffic over UDP feature, perform the tasks described in the following sections:

- Preparing to Configure Asynchronous Serial Traffic over UDP (Required)

- Configuring a Line for UDPTN (Required)

- Enabling UDPTN (Required)

- Verifying UDPTN Traffic (Optional but Recommended)

See the “UDPTN Configuration Examples” section at the end of this chapter for multicast, broadcast, and point-to-point UDPTN configuration examples.

Preparing to Configure Asynchronous Serial Traffic over UDP

When configuring the Asynchronous Serial Traffic over UDP feature for multicast transmission, you must configure IP multicast routing for the entire network that will receive or propagate the multicasts. When configuring the feature for broadcast transmission, you must configure broadcast flooding on the routers between network segments. Refer to the “Configuring IP Multicast Routing” chapter of this guide for information on how to configure IP multicast routing. See the section “Configuring Broadcast Packet Handling” in the Cisco IOS IP Configuration Guide for information on how to configure broadcast flooding.

Configuring a Line for UDPTN

To configure the line that will be used to send or receive UDP packets, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# line line-number

Enters line configuration mode for the line number specified.

Step 2

Router(config-line)# transport output udptn

Enables the line to transport UDP packets.

Step 3

Router(config-line)# dispatch-timeout 1000

Sends packets every 1000 milliseconds.

Step 4

Router(config-line)# dispatch-character 13

Sends packets after every new line.

Step 5

Router(config-line)# no session-timeout

Disables timeout connection closing.

Enabling UDPTN

There are two methods of enabling UDPTN. You can manually enable UDPTN when you want to begin transmission or reception, or you can configure the router to automatically enable UDPTN when a connection is made to the line.

Command

Purpose

Router# udptn ip-address [port] [/transmit] [/receive]

Enables UDPTN to the specified IP address (optionally, using the specified port). Use the /transmit or /receive keyword if the router will only be sending or receiving UDPTN.

To automatically enable UDPTN when a connection is made to the line, use the following commands beginning in global configuration mode:

Command

Purpose

Step 1

Router(config)# line line-number

Enters line configuration mode for the line number specified.

Step 2

Router(config-line)# autocommand udptn ip-address [port] [/transmit] [/receive]

Enables UDPTN automatically when a connection is made to the line (optionally, using the specified port). Use the /transmit or /receive keyword if the router will only be sending or receiving UDPTN.

Verifying UDPTN Traffic

To verify that UDPTN is enabled correctly, perform the following steps:

Step 1 Enable UDPTN debugging by using the debug udptn EXEC command.

Step 2 Enable UDPTN by using the udptn ip-address EXEC command, and then observe the debug output.

Router# show ip socket

Proto Remote Port Local Port In Out Stat TTY OutputIF

17 --listen-- 172.21.14.90 67 0 0 89 0

17 0.0.0.0 520 172.21.14.90 520 0 0 1 0

17 1.1.1.2 57 1.1.1.1 57 0 0 48 0

17 224.1.1.1 57 1.2.2.2 57 0 0 48 0 Loopback0

UDPTN Configuration Examples

This section provides the following UDPTN configuration examples:

- Multicast UDPTN Example

- Broadcast UDPTN Example

- Point-to-Point UDPTN Example

Multicast UDPTN Example

These configurations are for multicast UDPTN. The router that is multicasting does not require a multicast configuration—it simply sends to the multicast IP address.

Router That Is Multicasting

ip multicast-routing

interface ethernet 0

ip address 10.1.1.1 255.255.255.0

ip pim dense-mode

!

line 5

no session-timeout

transport output udptn

dispatch-timeout 10000

dispatch-character 13

modem in

autocommand udptn 172.1.1.1 /transmit

Receiving Routers

ip multicast-routing

interface ethernet 0

ip address 10.99.98.97 255.255.255.192

ip pim dense-mode

!

line 0 16

transport output udptn telnet lat rlogin

autocommand udptn 172.1.1.1 /receive

Broadcast UDPTN Example

These configurations are for broadcast UDPTN. This is the simplest method to send to multiple receivers. The broadcasting router sends to the broadcast IP address, and any router that wants to receive the transmission simply connects to the broadcast IP address by using the udptn command.

Router That Is Broadcasting

interface ethernet 0

ip address 10.1.1.1 255.255.255.0

!

line 5

no session-timeout

transport output udptn

dispatch-timeout 10000

dispatch-character 13

modem in

autocommand udptn 255.255.255.255 /transmit

Receiving Routers

interface ethernet 0

ip address 10.99.98.97 255.255.255.192

!

line 0 16

transport output udptn telnet lat rlogin

autocommand udptn 255.255.255.255 /receive

Point-to-Point UDPTN Example

These configurations are for two routers in mobile, unstable environments that wish to establish a bidirectional asynchronous tunnel. Because there is no way to ensure that both routers will be up and running when one of the routers wants to establish a tunnel, they cannot use connection-dependent protocols like Telnet or local area transport (LAT). They instead use the following UDPTN configurations. Each router is configured to send to and receive from the IP address of the other. Because both routers will be sending and receiving, they do not use the /transmit or /receive keywords with the udptn command.

Router A

interface ethernet 0

ip address 10.54.46.1 255.255.255.192

!

line 5

no session-timeout

transport output udptn

dispatch-timeout 10000

dispatch-character 13

modem in

autocommand udptn 10.54.46.2

Router B

interface ethernet 0

ip address 10.54.46.2 255.255.255.192

!

line 10

no session-timeout

transport output udptn

dispatch-timeout 10000

dispatch-character 13

modem in

autocommand udptn 10.54.46.1

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.

© 2001-2008 Cisco Systems, Inc. All rights reserved.