Routing

I found fast-reroute optimize-timer in the mpls configuration guide, but I'm not really understanding the purpose of this.

https://www.juniper.net/techpubs/en_US/junos10.4/information-products/topic-collections/config-guide-mpls-applications/index.html?topic-40162.html

https://www.juniper.net/techpubs/en_US/junos10.4/information-products/topic-collections/config-guide-mpls-applications/index.html?topic-40162.html

Based on my reading of this, it sounds like fast-reroute does not always use the best IGP metric to determine a detour. When you enable fast-reroute optimize-timer it will periodically choose a new detour for an LSP based if there is a better IGP path. It looks like this behavior is disabled by default... why wouldn't you want to turn this on if it provides this reoptimization ability?

Fast-reroute detour LSP's are not optimized, by default.  The purpose of this command is to set an interval for optimization of detour paths.

One reason an operator might not wish to optimize detour paths is to reduce the resource usage on the routing-engine.  Or possibly to decrease the amount of control-plane churn, in favor of the possible suboptimal detour path.

Ben