IS-IS flexible algorithm (FlexAlgo) provides a lightweight, simplified mechanism for performing basic traffic engineering functions within a single IS-IS area. FlexAlgo requires the cooperation of all nodes within the IS-IS area but does not require an external controller. Paths are computed by each node within the area, resulting in an MPLS switched forwarding path to nodes that are advertising a node Segment Identifier (SID) for the algorithm. The results of the path computation are placed in the colored tunnel RIB or system tunnel RIB, which simplifies route resolution.

Topology Independent Fast Reroute, or TI-LFA, uses IS-IS SR to build loop-free alternate paths along the post-convergence path. These loop-free alternates provide fast convergence.

Topology Independent Fast Reroute, or TI-LFA, uses OSPF SR to build loop-free alternate paths along the post-convergence path. These loop-free alternates provide fast convergence.