The BGP-LS extension allows IGP (OSPF/IS-IS) link state database information to be injected into BGP. This is typically used in deployments where some external component, (like a controller or Path Computation Engine) can do centralized path computations by learning the entire IGP topology through BGP-LS. The controller can then communicate the computed paths based on the BGP-LS updates to the head end device in the network. The mechanism used by the controller to communicate the computed TE paths is outside the scope of this document. Using BGP-LS instead of an IGP peering with the controller to distribute IGP link state information has the following advantages.

IS IS SR feature provides knobs to configure various types of segments which are distributed as part of IS IS LSPs (Link

This feature allows a user to configure multiple static adjacency SIDs for an IS IS adjacency. This feature is an

Segment Routing IS-IS 4.22.0F

Bidirectional Forwarding Detection (BFD) is a protocol that provides low-overhead, short-duration detection of failures of arbitrary paths between two systems.

Segment Routing Traffic Engineering Policy (SR TE) aka SR Policy makes use of Segment Routing (SR) to allow a headend

Segment Routing Traffic Engineering Policy (SR TE) aka SR Policy makes use of Segment Routing (SR) to allow a headend

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.