TOI Author :: Nandan Saha

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.

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.

By default if there's a hostname configured on the switch, it is used as the IS IS hostname. It is also possible to