Table Of Contents
SSG Direction Configuration for Interfaces and Ranges
Prerequisites for SSG Direction Configuration for Interfaces and Ranges
Restrictions for SSG Direction Configuration for Interfaces and Ranges
Information About SSG Direction Configuration for Interfaces and Ranges
Benefits of SSG Direction Configuration for Interfaces and Ranges
How to Configure SSG Direction for Interfaces and Ranges
Setting the Direction for an Interface
Setting the Direction for a PVC Range
Configuration Examples for SSG Direction Configuration for Interfaces and Ranges
Setting the Direction of an Interface: Example
Setting the Direction of a Range of PVCs: Example
Obsolete and Replaced Commands
SSG Direction Configuration for Interfaces and Ranges
The SSG Direction Configuration for Interfaces and Ranges feature introduces the ssg direction command. The ssg direction command replaces the ssg bind direction command. This new command streamlines and simplifies Service Selection Gateway (SSG) configuration by allowing you to configure interface direction, either uplink or downlink, for a range of subinterfaces at once.
Feature Specifications for the SSG Direction Configuration for Interfaces and Ranges
Feature History Release Modification12.2(16)B
This feature was introduced.
12.3(4)T
This feature was integrated into Cisco IOS Release 12.3(4)T.
Feature
Finding Support Information for Platforms and Cisco IOS Software Images
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Contents
•Prerequisites for SSG Direction Configuration for Interfaces and Ranges
•Restrictions for SSG Direction Configuration for Interfaces and Ranges
•Information About SSG Direction Configuration for Interfaces and Ranges
•How to Configure SSG Direction for Interfaces and Ranges
•Configuration Examples for SSG Direction Configuration for Interfaces and Ranges
Prerequisites for SSG Direction Configuration for Interfaces and Ranges
SSG must be enabled on the router.
Restrictions for SSG Direction Configuration for Interfaces and Ranges
You cannot use this command on an individual subinterface that is part of a permanent virtual circuit (PVC) range because all members of a range must have the same direction. You can use the command on the entire range only.
An interface that does not exist will not be created as a result of the ssg direction command.
Before you can change a direction from uplink to downlink, or the opposite, you must use the no ssg direction command to clear the direction. If you do not, you will receive an error message similar to the following:
Changing direction from Downlink to Uplink is denied for interface interfacePlease use `no ssg direction downlink' to clear the previous bind directionInformation About SSG Direction Configuration for Interfaces and Ranges
Before you configure the ssg direction command, you should understand the following concepts:
•Benefits of SSG Direction Configuration for Interfaces and Ranges
Overview of SSG
SSG is a switching solution for service providers who offer intranet, extranet, and Internet connections to subscribers using broadband access technology such as xDSL, cable modems, or wireless to allow simultaneous access to network services. It is a combined hardware and software solution that helps service providers provide differentiated kinds of services to users connecting through different mediums. SSG also offers user authentication and accounting features.
Interface Direction
SSG implements Layer 3 service selection through selective routing of IP packets to destination networks on a per-subscriber basis. SSG introduces the idea of interface direction (uplink/downlink) and uses this direction to help determine the forwarding path of an incoming packet. An uplink interface is an interface to services; a downlink interface is an interface to subscribers. You can set the direction by using the ssg direction command.
The ssg direction command can be configured on most of the interfaces supported by the interface command, including
•Async
•Group Async
•ATM
•Extended Tag ATM (XTagATM)
•Bridge Group Virtual (BVI)
•CTunnel
•Tunnel
•Dialer
•IEEE 802.3 Ethernet
•IEEE 802.3 Fast Ethernet
•IEEE 802.3z Gigabit Ethernet
•Loopback
•Multilink Frame Relay (MFR) bundle
•Multilink group
•Pragmatic General Multicast (PGM) Host (Vif)
•Virtual Access
•Virtual Template
•Virtual Token Ring
You can use the ssg direction command to configure the direction of a single interface or subinterface or a range of subinterfaces (ATM PVCs). If you configure a range, all members of the range must have the same direction, and you cannot configure members of a range individually.
Benefits of SSG Direction Configuration for Interfaces and Ranges
The new ssg direction command makes SSG configuration simpler and faster. For example, you can provision a large number of ATM routed bridge encapsulation (RBE) subscribers at once, instead of having to enter one command for each subscriber, which could mean entering thousands of commands. This feature enables streamlined provisioning and configuration, with decreased CPU load.
How to Configure SSG Direction for Interfaces and Ranges
This section contains the following procedures:
•Setting the Direction for an Interface
•Setting the Direction for a PVC Range
Setting the Direction for an Interface
Perform this task to configure an interface or subinterface as uplink or downlink. An uplink interface is an interface to services; a downlink interface is an interface to subscribers.
SUMMARY STEPS
1. enable
2. configure terminal
3. ssg enable
4. interface type number
5. ssg direction {downlink | uplink}
DETAILED STEPS
Troubleshooting Tips
Use the show ssg interface command in privileged EXEC mode to find out the direction of the interface.
Setting the Direction for a PVC Range
Perform this task to configure a range of subinterfaces as uplink or downlink. An uplink interface is an interface to services; a downlink interface is an interface to subscribers.
Restrictions
All subinterfaces in a range must have the same direction.
If you try to specify the direction of an interface that is part of a PVC range, you receive an error similar to the following:
PVC Range: Configuring interface is not allowed.SUMMARY STEPS
1. enable
2. configure terminal
3. ssg enable
4. interface atm interface-number.subinterface-number {mpls | multipoint | point-to-point}
5. range [range-name] pvc start-vpi/start-vci end-vpi/end-vci
6. exit
7. ssg direction {downlink | uplink}
DETAILED STEPS
Troubleshooting Tips
Use the show ssg interface command in privileged EXEC mode to find out the direction of the interface.
Configuration Examples for SSG Direction Configuration for Interfaces and Ranges
•Setting the Direction of an Interface: Example
•Setting the Direction of a Range of PVCs: Example
Setting the Direction of an Interface: Example
The following example shows how to configure Fast Ethernet interface 1/0 as a downlink interface:
ssg enableinterface FastEthernet 1/0ssg direction downlinkSetting the Direction of a Range of PVCs: Example
The following example show how to create a range called "MyRange" and set the direction of all subinterfaces in the range to downlink:
ssg enableinterface ATM 1/0.1 point-to-pointrange MyRange pvc 1/32 1/42exitssg direction downlink
Additional References
Consult the following references for information related to the SSG Direction Configuration for Interfaces and Ranges feature.
Related Documents
Standards
Standards TitleNo new or modified standards are supported by this feature. Support for existing standards has not been modified by this feature.
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MIBs
RFCs
RFCs TitleNo new or modified RFCs are supported by this feature. Support for existing RFCs has not been modified by this feature.
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Technical Assistance
Command Reference
This section documents the following new, modified, obsolete, and replaced commands. All other commands used with this feature are documented in the Cisco IOS Release 12.3 T command reference publications.
Obsolete and Replaced Commands
Table 1 lists those commands that have been replaced since Cisco IOS Release 12.2(16)B and Cisco IOS Release 12.3(4)T.
ssg bind direction
Note Effective with Cisco IOS Release 12.2(16)B, this command was replaced by the ssg direction command. The ssg bind direction command is still supported for backward compatibility, but support for this command will be removed in a future Cisco IOS release.
To specify an interface as a downlink or uplink interface, use the ssg bind direction command in global configuration mode. To disable the directional specification for the interface, use the no form of this command.
ssg bind direction {downlink | uplink} {ATM atm-interface | Async async-interface | BVI bvi-interface | Dialer dialer-interface | Ethernet ethernet-interface | FastEthernet fastethernet-interface | Group-Async group-async-interface | Lex lex-interface | Loopback loopback-interface | Multilink multilink-interface | Null null-interface | Port-channel port-channel-interface | Tunnel tunnel-interface | Virtual-Access virtual-access-interface | Virtual-Template virtual-template-interface | Virtual-TokenRing virtual-tokenring-interface}
no ssg bind direction {downlink | uplink} {ATM atm-interface | Async async-interface | BVI bvi-interface | Dialer dialer-interface | Ethernet ethernet-interface | FastEthernet fastethernet-interface | Group-Async group-async-interface | Lex lex-interface | Loopback loopback-interface | Multilink multilink-interface | Null null-interface | Port-channel port-channel-interface | Tunnel tunnel-interface | Virtual-Access virtual-access-interface | Virtual-Template virtual-template-interface | Virtual-TokenRing virtual-tokenring-interface}
Syntax Description
Defaults
All interfaces are configured as uplink interfaces by default.
Command Modes
Global configuration
Command History
Usage Guidelines
Use this command to specify an interface as downlink or uplink. An uplink interface is an interface to services; a downlink interface is an interface to subscribers.
Examples
The following example shows how to specify an ATM interface as a downlink interface:
Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)# ssg bind direction downlink ATM 0/0/0.10Related Commands
Command Descriptionshow ssg binding
Displays service names that have been bound to interfaces and the interfaces to which they have been bound.
ssg direction
To configure an interface or range of subinterfaces as downlink or uplink, use the ssg direction command in interface configuration mode or subinterface configuration mode. To clear the directional specification, use the no form of this command.
ssg direction {downlink | uplink}
no ssg direction
Syntax Description
Defaults
An interface is neither uplink nor downlink.
Command Modes
Interface configuration
Subinterface configurationCommand History
Release Modification12.2(16)B
This command was introduced.
12.3(4)T
This command was integrated into Cisco IOS Release 12.3(4)T.
Usage Guidelines
Service Selection Gateway (SSG) includes the concept of an interface direction, either uplink or downlink. It uses this direction when determining the forwarding path of an incoming packet. The ssg direction command allows you to specify a direction for an interface or a range of subinterfaces.
The command operates on a variety of interfaces, including async, group async, ATM, extended tag ATM (XTagATM), bridge group virtual (BVI), CTunnel, tunnel, dialer, IEEE 802.3 Ethernet, IEEE 802.3 Fast Ethernet, IEEE 802.3z GigabitEthernet, loopback, multilink Frame Relay (MFR) bundle, multilink group, Pragmatic General Multicast (PGM) Host (Vif), virtual access, virtual template, and virtual Token Ring.
The ssg direction command allows you to configure the direction for a range of PVCs. All members of a range must have the same direction.
If you try to configure the direction of a subinterface that is part of a PVC range, you receive an error similar to the following:
PVC Range: Configuring interface is not allowed.Before you can change a direction from uplink to downlink, or the opposite, you must use the no ssg direction command to clear the direction.
The ssg direction command replaces the ssg bind direction command. If you reboot a router that uses an old configuration, the ssg bind direction commands will be converted to ssg direction commands until the ssg bind direction command is made obsolete. In a later release, the ssg bind direction command will no longer be supported.
Note An interface that does not exist will not be created as a result of the ssg direction command.
Examples
The following example sets the direction of a Fast Ethernet interface to downlink while in interface configuration mode:
ssg enableinterface FastEthernet 1/0ssg direction downlinkThe next example creates a range called "MyRange" and sets the direction of all subinterfaces in the range to downlink while in subinterface configuration mode:
ssg enableinterface ATM 1/0.1 point-to-pointrange MyRange pvc 1/32 1/42ssg direction downlinkRelated Commands
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