Table Of Contents

Control Point Discovery on the Cisco CMTS Routers

Contents

Prerequisites for Control Point Discovery

Restrictions for Control Point Discovery

Information About Control Point Discovery

Control Points

Network Layer Signaling (NLS)

NLS for CPD

Control Point Discovery

CPD Protocol Hierarchy

Control Relationship

How to Configure CPD

Enabling CPD Functionality

Prerequisites

Examples

Configuring Control Relationship Identifier

Examples

Enabling NLS Functionality

Examples

Configuring Authorization Group Identifier and Authentication Key

Examples

Configuring NLS Response Timeout

Examples

Additional References

Related Documents

Standards

Technical Assistance

Feature Information for Control Point Discovery

Control Point Discovery on the Cisco CMTS Routers

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Revised: February 14, 2008, Cisco IOS Release 12.2(33)SCA

First Published: Cisco IOS Release 12.3(21a)BC3

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Note Cisco IOS Release 12.2(33)SCA integrates support for this feature on the Cisco CMTS routers. This feature is also supported in Cisco IOS Release 12.3BC, and this document contains information that references many legacy documents related to Cisco IOS 12.3BC. In general, any references to Cisco IOS Release 12.3BC also apply to Cisco IOS Release 12.2SC. For the latest information on Cisco CMTS router support in Cisco IOS Release 12.2SC, refer to the Cross-Platform Release Notes for Cisco Universal Broadband Routers in Cisco IOS Release 12.2SC.

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This document describes the Control Point Discovery (CPD) feature. This feature, along with Network Layer Signaling (NLS), enables automatic discovery of any control point associated with an end point.

Finding Feature Information in This Module

Your Cisco IOS software release may not support all of the features documented in this module. To reach links to specific feature documentation in this module and to see a list of the releases in which each feature is supported, use the "Feature Information for Control Point Discovery" section on page 24.

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 Control Point Discovery

•Restrictions for Control Point Discovery

•Information About Control Point Discovery

•How to Configure CPD

•Additional References

•Feature Information for Control Point Discovery

Prerequisites for Control Point Discovery

The Control Point Discovery feature is supported on the Cisco CMTS routers in Cisco IOS Release 12.3BC and 12.2SC. Table 1 shows the hardware compatibility prerequisites for this feature.

Table 1 Control Point Discovery Hardware Compatibility Matrix

CMTS Platform	Processor Engine	Cable Interface Cards
Cisco uBR10012 Universal Broadband Router	Cisco IOS Release 12.2(33)SCA •PRE-2	Cisco IOS Release 12.2(33)SCA •Cisco uBR10-MC5X20S/U/H
Cisco uBR7246VXR Universal Broadband Router	Cisco IOS Release 12.2(33)SCA •NPE-G1 •NPE-G2	Cisco IOS Release 12.2(33)SCA •Cisco uBR-MC28U/X •Cisco uBR-MC16U/X
Cisco uBR7225VXR Universal Broadband Router	Cisco IOS Release 12.2(33)SCA •NPE-G1	Cisco IOS Release 12.2(33)SCA •Cisco uBR-E-28U •Cisco uBR-E-16U •Cisco uBR-MC28U/X •Cisco uBR-MC16U/X

Restrictions for Control Point Discovery

•The CPD feature does not sync any dynamic CPD/NLS related data between the route processors (RPs). After sending a NLS challenge to the controller, the new active PRE will ignore the NLS response as a result of any RP switchover.

•The CPEs become inaccessible for a small duration during line card switchovers. During this interval, any CPD request received on CMTS will be responded to as if the endpoint is not connected or as if the control relationship is not supported.

•The CPD functionality is restricted to default VPN table id (0).

•Only manual configuration of NLS authentication pass phrase would be supported for CPD/NLS security.

•For NLS authentication, HMAC SHA1 (no configuration option) is used with MAC length truncated to 96 bits.

Information About Control Point Discovery

To configure the Control Point Discovery feature, you should understand the following concepts:

•Control Points

•Network Layer Signaling (NLS)

•Control Point Discovery

Control Points

Control points are points in a network that can be used to apply certain functions and controls for a media stream. In a cable environment, the control points are Cable Modem Termination Systems (CMTS) and devices that utilizes these control points are referred to as CPD Requestors (or controllers).

Cable CPD Requestors include the following:

•Call Management Server (CMS)

•Policy Server (PS)

•Mediation Device for Lawful Intercept (MD)

Network Layer Signaling (NLS)

Network Layer Signaling (NSL) is an on-path request protocol used to carry topology discovery and other requests in support of various applications. In the CPD feature, NLS is used to transport CPD messages.

NLS for CPD

NLS is used to transport CPD messages. The CPD data is carried under an application payload of the NLS and contains a NLS header with flow id. The NLS flow id is used during NLS authentication to uniquely identify the CPD requests and responses for an end point of interest.

NLS Flags

All NLS headers contain bitwise flags. The CMTS expects the following NLS flag settings for CPD applications:

•HOP-BY-HOP = 0

•BUILD-ROUTE = 0

•TEARDOWN = 0

•BIDIRECTOINAL = 0

•AX_CHALLANGE = 0/1

•AX_RESPONSE = 0/1

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Note Any requests with flags other then AX flags, set to one will be rejected with an error indicating a poorly formed message.

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NLS TLVs

The following NLS TLVs are supported for all CPD applications:

•APPLICATION_PAYLOAD

•IPV4_ERROR_CODE

•IPV6_ERROR_CODE

•AGID

•A_CHALLENGE

•A_RESPONSE

•B_CHALLENGE

•B_RESPONSE

•AUTHENTICATION

•ECHO

The following NLS TLVs are not supported for CPD applications:

•NAT_ADDRESS

•TIMEOUT

•IPV4_HOP

•IPV6_HOP

Control Point Discovery

The control point discovery feature allows CPD Requestors to determine the control point IP address between the CPD Requestor and the media endpoint.

Using Networking Layer Signaling (NLS), the control point discovery feature sends a CPD message towards the end point (MTA). The edge/aggregation device (CMTS), located between the requestor and the endpoint, will respond to the message with its IP address.

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Note For Lawful Intercept, it is important that the endpoint does not receive the CPD message. In this instance, the CMTS responds to the message without forwarding it to its destination.

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CPD Protocol Hierarchy

CPD messages are sent over the NLS.

The CPD Protocol Hierarchy is as follows:

1. CPD

2. NLS

3. UDP

4. IP

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Note Since NLS is implemented on the UDP protocol, there is a potential of message loss. If messages are lost, the controller will re-send the CPD request in any such event.

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Control Relationship

A control relationship between a control point and a controller is identified as a function on a media flow that passes through a control point. A control relationship is uniquely defined by a control relationship type (CR TYPE) and control relationship ID (CR ID). The CR ID is provisioned on CMTS as well as the controller.

Table 3 lists the supported CR TYPEs and corresponding pre-defined CR IDs

Table 2 Supported Control Relationship Types and Corresponding Control Relationship IDs

Control Relationship Type	Pre-Defined Corresponding Control Relationship ID
CR TYPE = 1 (Lawful Intercept)	CR ID = 1: CMTS
	CR ID = 2: Aggregation router or switch in front of CMTS
	CR ID = 3: Aggregation router or switch in front of Media Services
	CR ID = 4: Media Gateway
	CR ID = 5: Conference Server
	CR ID = 6: Other
CR TYPE = 2 (DQoS)	CR ID = 1: CMTS
CR TYPE = 3 (PCMM)	CR ID = 1: CMTS

How to Configure CPD

This section contains the following tasks:

•Enabling CPD Functionality

•Configuring Control Relationship Identifier

•Enabling NLS Functionality

•Configuring Authorization Group Identifier and Authentication Key

•Configuring NLS Response Timeout

Enabling CPD Functionality

To enable the CPD functionality, use the cpd command in global configuration mode. The CPD message authentication is determined by NLS configuration.

Prerequisites

The CPD message authentication is determined by NLS configuration.

SUMMARY STEPS

1. enable

2. configure terminal

3. cpd

4. end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	cpd Example: Router (config)# cpd	Enables CPD functionality •Us the "no" form of this command to disable CPD functionality.
Step 4	end Example: Router# end	Exits global configuration mode and enters privileged EXEC mode.

Examples

The following example shows the cpd enabled on a router:

Router (config)# cpd

Configuring Control Relationship Identifier

To configure a Control relationship identifier (CR ID) for CMTS, use the cpd cr-id command. When CPD request comes with a wild-card CR ID, the CMTS will respond with this configured value.

SUMMARY STEPS

1. enable

2. configure terminal

3. cpd cr-id

4. end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	cpd cr-id Example: Router (config)# cpd cr-id 100	Configures a control relationship identifier (CR ID) for CMTS. •The cr-id can be from 1 to 65535. •The default cr-id is configured as 1 (CMTS).
Step 4	end Example: Router# end	Exits global configuration mode and enters privileged EXEC mode.

Examples

The following example shows the cpd cr-id command configured with a cr-id number of 100 on a router.

Router (config)# cpd cr-id 100

Enabling NLS Functionality

To enable the NLS functionality, use the nls command in global configuration mode. It is recommended that NLS message authentication be enabled at all times.

SUMMARY STEPS

1. enable

2. configure terminal

3. nls

4. debug nls

5. end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	nls Example: Router (config)# nls	Enables NLS functionality. •NLS authentication is optional. •It is recommended that NLS message authentication be enabled at all times.
Step 4	debug nls Example: Router# debug nls	Enables NLS debug functionality.
Step 5	end Example: Router# end	Exits global configuration mode and enters privileged EXEC mode.

Examples

The following example shows the nls command enbaled on a router.

Router (config)# nls

Configuring Authorization Group Identifier and Authentication Key

The Authorization Group Identifier (AG ID) and corresponding authorization key are provisioned on CMTS, as well as on controller/CPD requester.

To configure the Authorization Group Identifier and Authentication Key, use the nls ag-id command in global configuration mode. It is recommended that NLS message authentication be enabled at all times.

SUMMARY STEPS

1. enable

2. configure terminal

3. nls ag-id

4. debug nls

5. end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	nls ag-id Example: Router (config)# nls ag-id 100 auth-key 20	Configures the Authorization Group Identifier and Authentication Key. •Authorization Group ID (AG ID) can range from 1 to 4294967294. •Authentication Keys can range from 20 to 64.
Step 4	debug nls Example: Router (config)# debug nls	Enables NLS debug functionality.
Step 5	end Example: Router# end	Exits global configuration mode and enters privileged EXEC mode.

Examples

The following example shows the nls ag-id command with an Authorization Group ID of 100 and Authentication Key of 20.

Router (config)# nls ag-id 100 auth-key 20

Configuring NLS Response Timeout

The NLS response timeout governs the time CMTS will wait for getting a response for a NLS authentication request.

To configure the NLS response timeout, use the nls ag-id command in global configuration mode. It is recommended that NLS message authentication be enabled at all times.

SUMMARY STEPS

1. enable

2. configure terminal

3. nls resp-timeout

4. debug nls

5. end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	nls resp-timeout Example: Router (config)# nls resp-timeout 60	Configures the NLS response time. •NLS response times can range from 1 to 60 seconds. •NLS response time has a default setting of 1 second.
Step 4	debug nls Example: Router (config)# debug nls	Enables NLS debug functionality.
Step 5	end Example: Router# end	Exits global configuration mode and enters privileged EXEC mode.

Examples

The following example shows the nls resp-timeout command with a response timeout setting of 60 seconds.

Router (config)# nls resp-timeout 60

Additional References

The following sections provide references related to the CPD feature.

Related Documents

Related Topic	Document Title
CMTS features	•Cisco IOS CMTS Cable Software Configuration Guide •Managed Broadband Access Using MPLS VPNs for Cable Multiservice Operators •Transparent LAN Service over Cable •Troubleshooting the System

Standards

Standard	Title
Internet Draft, Network Layer Signaling: Transport Layer	Internet Draft, Network Layer Signaling: Transport Layer (IETF draft-shore-nls-tl-05.txt)
PacketCable™ Control Point Discovery Interface Specification	PacketCable™ Control Point Discovery Interface Specification (PKT-SP-CPD-I02-061013)

Technical Assistance

Description

Link

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http://www.cisco.com/techsupport

Feature Information for Control Point Discovery

Table 3 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.

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Note Table 3 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.

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Table 3 Feature Information for <Phrase Based on Module Title> 

Feature Name	Releases	Feature Information
Control Point Discovery	12.3(21a)BC3	The control point discovery feature allows CPD Requestors to determine the control point IP address between the CPD Requestor and the media endpoint. The following commands were introduced or modified by this feature: •cpd •cpd cr-id •debug cpd •debug nls •nls •nls ag-id auth-key •nls resp-timeout •show cpd •show nls •show nls ag-id •show nls flow
Control Point Discovery	12.2(33)SCA	This feature was integrated into Cisco IOS Release 12.2(33)SCA. Support for the Cisco uBR7225VXR Universal Broadband Router was added.

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