Shared segment recovery mechanism in optical networks

A fast recovery mechanism from a failure is one of important requirements in optical networks. We have already proposed a fast recovery mechanism. In the proposal, recovery paths are pre-configured prior to a failure. A fault detecting node floods fault notification messages when a failure happens. Nodes receiving the message activate pre-configured recovery paths. Multiple paths affected by the failure are simultaneously and immediately recovered. In the proposal, simple calculation is done and it gets the pre-configured recovery paths which detour around a link on its working path. Consequently, it increases the total amount of resources to reserve for recovery paths as well as the number of recovery paths. This paper proposes an algorithm to calculate a segment detour path. The calculated paths enable a recovery within a required period and they save network resources with sharing network resources among other recovery paths. Furthermore, they protect segment with a group of nodes and links on the working path. Therefore the algorithm reduces the number of recovery paths and the amount of resources for recovery in a network. This paper also shows the performance of the proposed algorithm by using simulation results