IP FRR configuration

First, the user enables LFA computation by SPF under the IS-IS routing protocol level or under the OSPF routing protocol instance level using the following commands:

The preceding commands instruct the IGP SPF to attempt to precompute both a primary next hop and an LFA next hop for every learned prefix. When found, the LFA next hop is populated into the RTM along with the primary next hop for the prefix.

After enabling LFA computation, the user enables IP FRR using the following commands to cause RTM to download to the IOM or the forwarding engine an LFA next hop, when found by SPF, in addition to the primary next hop for each prefix in the FIB.

Parent topic: IP Fast-Reroute for OSPF and IS-IS prefixes