Path protection for ring-based multi-protocol label switched paths

摘要

Techniques are described for specifying and constructing multi-protocol label switching (MPLS) rings. Routers may signal membership within MPLS rings and automatically establish ring-based label switch paths (LSPs) as components of the MPLS rings for packet transport within ring networks. In one example, a router includes a processor configured to establish an MPLS ring having a plurality of ring LSPs. Each of the ring LSPs is configured to transport MPLS packets around the ring network to a different one of the routers operating as an egress router for the respective ring LSP. Moreover, each of the ring LSPs comprises a bidirectional, multipoint-to-point (MP2P) LSP for which any of the routers can operate as an ingress to source packet traffic into the ring LSP for transport to the respective egress router for the ring LSP. Separate protection paths, bypass LSPs, detours or loop-free alternatives need not be signaled.

主权项

1. A method comprising:
establishing, with a plurality of routers connected to form a ring network, a ring label switched path (LSP) configured to transport multi-protocol label switching (MPLS) packets around the ring network to one of the routers operating as an egress router for the ring LSP, wherein the ring LSP comprises a bidirectional multipoint-to-point (MP2P) LSP for which any of the routers within the ring network can operate as an ingress to source packet traffic into the ring LSP for transport to the egress router for the ring LSP in an upstream direction and a downstream direction around the ring network, wherein establishing a ring LSP comprises outputting, from each of the routers, a first label distribution message in a upstream direction with respect to the ring network and a second label distribution message in a downstream direction with respect to the ring network, and wherein the first label distribution message and the second label distribution message output by each of the routers includes an identifier for an MPLS ring associated with the ring network and an identifier for the one of the plurality of routers that operates as the egress router for the ring LSP; forwarding network traffic as MPLS packets around the ring network in the downstream direction to the egress router in accordance with the ring LSP; detecting, with any one of the routers, a network event that would prevent the MPLS packets from reaching the egress router in the downstream direction; and responsive to detecting the network event, automatically redirecting the MPLS packets at the one of the routers detecting the network event from the downstream direction of the ring LSP to the upstream direction of the ring LSP to forward the MPLS packets around the ring in the upstream direction to the egress router.