Abstract: Network devices provide Internet Protocol (IP) and Label Distribution Protocol (LDP) fast reroute for unicast and multicast traffic. The approach described herein for fast reroute for IP and LDP uses maximally redundant trees (MRTs). MRTs are a pair of trees where the path from any node X to the root R along the first tree and the path from the same node X to the root along the second tree share the minimum number of nodes and the minimum number of links. A network device, such as a router, computes a pair of MRTs for each destination and installs one or more MRT alternate next-hops in its forwarding plane for use in forwarding network traffic to a destination in the event a failure occurs that renders a primary next-hop unusable for reaching the destination.

Abstract: A packet-forwarding integrated circuit includes a control logic module and a selector block configured to produce a value indicating an incoming interface associated with a multicast data stream that meets stream health requirements, wherein the multicast data stream is one of a plurality of redundant multicast data streams each received on different incoming interfaces, wherein based on the value produced by the selector block the control logic module outputs data packets of the multicast data stream that meets stream health requirements received on the incoming interface, and discards data packets of other multicast data streams received on other incoming interfaces not indicated by the selector block. In response to detecting that a quality of one of the redundant multicast data streams has fallen below a configured threshold, the control logic automatically rewrites the selector block to forward a different one of the redundant multicast data streams.