Patent ID: 7969890

Claim:
A system for obtaining a symmetric shortest-path-first (SPF) path selection from a source IP device to a destination IP device through a network, the system comprising: a source IP device comprising: (a) a cost table for storing output interface costs for reaching the destination IP device from the source IP device, wherein the cost table is configured to store an output interface cost advertised in a first direction over a first network segment between the source IP device and the destination IP device and an output interface cost advertised in a second direction over the first network segment that is different from the output interface cost advertised in the first direction over the network segment; (b) a router instance embodied in a memory for identifying a plurality of paths between the source IP device and the destination IP device, for calculating a cost of each path, for ranking the paths based on the calculated costs, and for assigning outbound packets of a media session to a lowest cost path; and (c) wherein calculating a cost for each path includes, for paths that include the first network segment, substituting the output interface cost advertised in the first direction over the first network segment with the output interface cost advertised in the second direction over the first network segment.