32An Introduction to IP Routing Protocols

Virtual link diagram

Note: Stub or NSSA areas cannot be transit areas.

A virtual link can be created manually or automatically.

Manual virtual link creation can conserve resources and provide specific control of virtual link placement in the OSPF configuration.

To add a virtual link manually, configure both endpoint ABRs with a neighbor router ID and transit area ID. You can configure up to 16 virtual links.

Note: You can modify parameters for manually added virtual links.

To accept automatic virtual link creation, enable automatic virtual link on both endpoint ABRs (the default value is disabled). Automatic virtual links are removed when the transit area is deleted, auto virtual link is disabled, or the router is no longer an ABR.

Note: Auto-created virtual links use default settings that cannot be modified.

Example Configuration

Consider the following situation:

Nortel Ethernet Routing Switch 5500 Series

Configuration-IP Routing Protocols

NN47200-503 03.01 Standard

5.127 August 2007

Copyright © 2005-2007, Nortel Networks

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Nortel Networks NN47200-503 manual Example Configuration, Consider the following situation, Virtual link diagram