Local protection

Each path may be locally protected through the network using LFA/remote-LFA nexthop whenever possible. The protection of a SID node re-uses the LFA and remote LFA features introduced with segment routing shortest path tunnels; the protection of an adjacency SID has been added to the SR OS in the specific context of an SR-TE LSP to augment the protection level. The user must enable the loopfree-alternates remote-lfa option in IS-IS or OSPF.

This behavior is already supported in the SR shortest path tunnel feature at both LER and LSR. As such, an SR-TE LSP that transits at an LSR and that matches the ILM of a downstream SID node automatically takes advantage of this protection when enabled. If required, SID node protection can be disabled under the IGP instance by excluding the prefix of the SID node from LFA.