The BGP-LS extension allows IGPs (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.

OSPF supports all of RFC3630 and parts of RFC4203. When configured, OSPF generates the following information in

Segment Routing Traffic Engineering Policy (SR-TE) aka SR Policy makes use of Segment Routing (SR) to allow a headend to steer traffic along any path without maintaining per flow state in every node. A headend steers traffic into an “SR Policy”. EOS 4.21.0F added support for SR Policy for the MPLS dataplane (SR-MPLS) for Type-1 SR Policy segments in single agent routing model. EOS 4.22.1F adds support for SR-TE in multi-agent routing model.

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