A method for identifying and choosing a shortest path segment that has an alternate
edge disjoint path segment. While routing Unidirectional Path Switched Ring (UPSR)
path segments in a graph, there may be several equal distance paths to choose the
shortest path from. Choosing a certain path as the shortest path may minimize or
eliminate the chance of finding an alternative path segment. A method is provided
such that if multiple shortest paths from the source node to a particular destination
node exist, the method selects the shortest path which has an alternate edge disjoint
path, and which can be used for path protection. The particular shortest path chosen
by the method is not necessarily the first shortest path constructed.
