BGP-LS Advertisement of Segment Routing Service Segments

BGP Link-State (BGP-LS) enables distribution of topology information from the network to a Path Computation Engine (PCE) or any controller/application in general so it can learn the network topology. Service functions are deployed as, physical or virtualized elements along with network elements or on servers in data centers. The advertisement of such attached service capabilities along with the network nodes that they are attached to or associated with enables their discovery and the programming of service paths that use these service functions. Segment Routing (SR) brings in the concept of segments which can be topological or service instructions. SR Policies enable the setup of paths which are a mix of topological and service segments. This document specifies the extensions to BGP-LS for discovery and advertisement of service segments to enable the setup of service programming paths using Segment Routing.