A New Algorithm to Compute Alternate Paths in Reliable OSPF (ROSPF)

Alternate paths may significantly improve reliability of routing protocols. We develop a fast alternate path-finding algorithm for our proposed Reliable OSPF (ROSPF) routing protocol. This algorithm is based on the Dijkstra’s shortest path algorithm and a logarithmic edge-increment procedure. Three partially disjoint paths can be calculated in time complexity O(N*logN*logW0), where N and W0 represent the number of nodes and the sum of the weights of all edges in a graph, respectively. We use simulation tests to compare the performance of our algorithm and the MPS K shortest paths algorithm that uses the deviation approach. Based on the results of simulation, our algorithm is proved to be an efficient alternate path-finding method with several advantages such as simpler implementation, faster execution time, better stability and fewer shared edges in a selected path set.