TI-LFA SRLG Protection for OSPF

This feature introduces support for Shared Risk Link Group (SRLG) protection in topology-independent loop-free alternate (TI-LFA) networks for segment routing to choose a fast reroute path that does not include SRLG links in the TI-LFA backup paths. SRLGs share a common fiber, and they also share the risks of a broken link. When one link in an SRLG fails, other links in the group might also fail. Therefore, you need to avoid links that share the same risk as the protected link in the backup path. Configuring SRLG protection prevents TI-LFA from selecting backup paths that include a shared-risk link. If you have configured SRLG protection, then OSPFv2 computes the fast reroute path that is aligned with the post convergence path and excludes the links that belong to the SRLG of the protected link. All local and remote links that are from the same SRLG as the protected link are excluded from the TI-LFA backup path. The point of local repair (PLR) sets up the label stack for the fast reroute path with a different outgoing interface. Currently, you cannot enable SRLG protection in IPv6 networks and in networks with multitopology.