Configuring Route Redistribution

Exporting routes from one protocol to another and in the reverse direction are discrete configuration functions. For example, to run IS-IS and RIP (Routing Information Protocol) simultaneously, you must first configure both protocols and then verify the independent operation of each. Then you can configure the routes to export from IS-IS to RIP and the routes to export from RIP to IS-IS. Likewise, for any other combinations of protocols, you must separately configure each to export routes to the other.

This section describes how to inject routing information learned from other IP routing protocols into an IS-IS domain, thereby advertising their reachability in the IS-IS domain. These routes are included in the locally originated LSPs. For information on exporting routes learned in IS-IS to another routing protocol, see the chapter that describes the destination routing protocol.

When you export routes from another protocol to IS-IS, the metric and the type of metric are configured. You can also configure a policy to filter out unwanted external routes.

To enable or disable the exporting of BGP (Border Gateway Protocol), OSPF (Open Shortest Path First), RIP, static, and direct (interface) IPv4 routes to IS-IS, use the following commands:
enable isis area area_name export {ipv4} route-type [policy | metric mvalue {metric-type [internal | external]}] {level[1| 2 | both-1-and-2]}

disable isis area area_name export {ipv4} route-type
To enable or disable the exporting of OSPFv3 (Open Shortest Path First version 3), RIPng (Routing Information Protocol Next Generation), static, and direct (interface) IPv6 routes to IS-IS, use the following commands:

enable isis area area_name export ipv6 route-type [policy | metric mvalue] {level[1| 2 | both-1-and-2]}

disable isis area area_name export ipv6 route-type

The cost metric is inserted for all OSPF, RIP, static, and direct routes injected into IS-IS.

The same cost and type values can be inserted for all the export routes, or policies can be used for selective insertion. When a policy is associated with the export command, the policy is applied on every exported route. The exported routes can also be filtered using policies.
Verify the configuration using the command:
show isis area [area_name | all]

Published March 2020prev | next

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