Path Computation Element Communication Protocol (PCEP) Extensions for Associated Bidirectional Segment Routing (SR) LSPs

Segment Routing (SR) steers packets through a network using the IPv6 or MPLS data planes via source routing. Stateful Path Computation Element Communication Protocol (PCEP) extensions are defined for SR Traffic Engineering (TE) LSPs. PCEP supports grouping two RSVP-TE signaled, unidirectional MPLS-TE Label-Switched Paths (LSPs) with one in each direction in a network into an associated bidirectional LSP. This document extends PCEP support to group two unidirectional SR LSPs into an associated bidirectional SR LSP. The mechanisms defined in this document apply to both stateless and stateful PCEs for PCE-initiated and PCC- initiated LSPs.