Patent ID: 7830785

Claim:
A method of modifying IP backbone link weights such that multicast traffic and unicast traffic will travel on disjoint paths between nodes, the method comprising: assigning link weights to nodes within an IP backbone such that multicast forwarding paths and unicast forwarding paths are failure disjoint to yield assigned link weights, wherein the IP backbone is an undirected network graph that is at least 2-connected; and delivering undelivered multicast packets using IP unicast encapsulation to a next hop router on a multicast tree upon network failure, and wherein the assigned link weights are determined by: (a) starting from a source node, locating a series of network links that form a ring; (b) initializing a graph as nodes and links of the ring; (c) initializing weights along one direction of the ring as high cost and in another direction as low cost; and (d) iteratively adding links without weights to the graph by finding a series of links that form a chain whose endpoints terminate at the graph, wherein unidirectional links in one direction have a high cost and unidirectional links in another direction have a low cost, until all links are assigned weights.