Configuring IS-IS Route Aggregation
To improve the route searching efficiency and simplify route management on a large-scale IS-IS network, configure IS-IS route summarization to reduce the number of IS-IS routes in a routing table.
Context
Route summarization is used to summarize routes with the same IP prefix into one route.
On a large-scale IS-IS network, route summarization can be configured to reduce the number of IS-IS routes in a routing table. This summarization improves the usage of system resources and facilitates route management.
If a link on an IP network segment that is summarized frequently alternates between Up and Down states, IP network segments that are not summarized will not be affected, preventing route flapping and improving the network stability.
Procedure
- Access the system view.
- Access the IS-IS process view.
isis [ process-id ]
- Configure IS-IS route aggregation.
summary ip-address mask [ avoid-feedback | generate_null0_route | tag tag | [ level-1 | level-1-2 | level-2 ] ] *
After route summarization is configured on an IS, the local routing table still contains all specific routes before the summarization.
The routing tables on other ISs contain only the summary route, and the summary route is deleted only after all its specific routes are deleted.