Method for fast-re-routing (FRR) in communication networks

摘要

A method is described to enable carrying out a fast reroute protection technique which provides both link and node protection without traffic duplication, without the need to distinguish between link and node failures, and without replicating traffic. The technique covers concurrent Working and backup logical path failures, and in particular LSP logical paths. The method is adapted to provide a “Dual Failure Protection” (DFP), and is expandable to various multi-failure scenarios.

主权项

1. A method for fast rerouting (FRR) of traffic in a communication network, from a Working path comprising a first node being a point of local repair (PLR), a link connecting the first node with a second, downstream node being a next hop node (NH), and a third node positioned downstream to said second node along said Working path being a next-next hop node (NNH); the method comprises:
pre-provisioning a point-to-multipoint (P2MP) backup path having a start point at the PLR and two termination points being the NH and the NNH, pre-provisioning, in said P2MP backup path, a node PH being a penultimate hop to the NH, so that the PH is directly connected to the NH; wherein the P2MP backup path comprising two sub-paths, a first extending between the PLR and the NH, and a second between the PLR and the NNH, and wherein the two sub-paths are identical until they branch off at the penultimate hop (PH); concurrently providing link protection against failure of said link between the PLR and NH, and node protection against failure of said NH, thereby ensuring concurrent FRR for said link and said NH by implementing at said PH node a forwarding rule enabling to forward traffic, if received at the PH along said P2MP backup path, towards said NH in case the NH is UP, and downstream the P2MP backup path towards said NNH in case said the NH is DOWN.