OSPF Area Transit Capability
First Published: January 27, 2004
Last Updated: May 4, 2009
The OSPF Area Transit Capability feature provides an OSPF Area Border Router (ABR) with the ability to discover shorter paths through the transit area for forwarding traffic that would normally need to travel through the virtual-link path. This functionality allows Cisco IOS XE software to be compliant with RFC 2328, OSPF Version 2.
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 OSPF Area Transit Capability" section.
Use Cisco Feature Navigator to find information about platform support and Cisco IOS XE 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 OSPF Area Transit Capability
•How to Disable OSPF Area Transit Capability
•Additional References
•Feature Information for OSPF Area Transit Capability
Information About OSPF Area Transit Capability
How the OSPF Area Transit Capability Feature Works
The OSPF Area Transit Capability feature is enabled by default. RFC 2328 defines OSPF area transit capability as the ability of the area to carry data traffic that neither originates nor terminates in the area itself. This capability enables the OSPF ABR to discover shorter paths through the transit area and to forward traffic along those paths rather than using the virtual link or path, which is not optimal.
For a detailed description of OSPF area transit capability, see RFC 2328, OSPF Version 2.
How to Disable OSPF Area Transit Capability
Disabling OSPF Area Transit Capability on an Area Border Router
SUMMARY STEPS
1. enable
2. configure terminal
3. router ospf process-id [vrf vpn-name]
4. no capability transit
DETAILED STEPS
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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 ospf process-id [vrf vpn-name]
Router(config)# router ospf 100 |
Enables OSPF routing and enters router configuration mode. •The process-id argument identifies the OSPF process. |
Step 4 |
no capability transit
Router(config-router)# no capability transit |
Disables OSPF area transit capability on all areas for a router process. |
Additional References
The following sections provide references related to the OSPF Area Transit Capability feature.
Related Documents
Standards
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No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature. |
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MIBs
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No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature. |
To locate and download MIBs for selected platforms, Cisco IOS XE releases, and feature sets, use Cisco MIB Locator found at the following URL: http://www.cisco.com/go/mibs |
RFCs
Technical Assistance
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The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password. |
http://www.cisco.com/cisco/web/support/index.html |
Feature Information for OSPF Area Transit Capability
Table 1 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 Cisco IOS XE 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 XE software release that introduced support for a given feature in a given Cisco IOS XE software release train. Unless noted otherwise, subsequent releases of that Cisco IOS XE software release train also support that feature.
Table 1 Feature Information for OSPF Area Transit Capability
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OSPF Area Transit Capability |
Cisco IOS XE Release 2.1 |
The OSPF Area Transit Capability feature provides an OSPF Area Border Router (ABR) the ability to discover shorter paths through the transit area for forwarding traffic that would normally need to travel through the virtual-link path. This functionality allows Cisco IOS XE software to be compliant with RFC 2328. The command related to this feature is •capability transit |
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