IETF RFC 8537 PDF

Resource Reservation Protocol (RSVP) association signaling can be used to bind two unidirectional Label Switched Paths (LSPs) into an associated bidirectional LSP. When an associated bidirectional LSP is co-routed, the reverse LSP follows the same path as its forward LSP. This document updates the fast reroute procedures defined in RFC 4090 to support both single-sided and double-sided provisioned associated bidirectional LSPs. This document also updates the procedure for associating two reverse LSPs defined in RFC 7551 to support co-routed bidirectional LSPs. The fast reroute procedures can ensure that, for the co-routed LSPs, traffic flows on co-routed paths in the forward and reverse directions after a failure event.