Patent ID: 8264949

Claim:
A method of circumventing a local failure by a node in a link state protocol controlled network in which nodes on the network forward traffic on the network using shortest path forwarding, the method comprising the steps of: determining, by the node, a primary neighbor node for a destination node, the primary neighbor node being a neighbor node on a shortest path on the network from the node to the destination node; determining, by the node, a set of potential loop free alternate neighbor nodes that have installed shortest path forwarding state to the destination node, the installed shortest path forwarding state enabling each of the set of potential loop free alternate neighbor nodes to forward traffic received at the neighbor node and addressed to the destination node to follow a shortest path through the network that does not pass through the node and does not pass through the primary neighbor node, the set of potential loop free alternate neighbor nodes not including the primary neighbor node; applying, by the node, weighting information to select at least one of the potential loop free alternate neighbor nodes as a first hop for use in forwarding traffic to the destination node upon occurrence of a failure at the primary neighbor node; and upon occurrence of the failure at the primary neighbor node, forwarding the traffic for the destination node to the selected loop free alternate neighbor node to enable the selected loop free alternate neighbor node to forward the traffic using its installed shortest path forwarding state toward the destination node without encapsulating the traffic using a new network address.