Iteration-free node-disjoint paths search in WDM networks with asymmetric nodes

Provisioning of a pair of disjoint paths is crucial in WDM network planning and management in order to provide fault tolerant services. However, in networks with asymmetric nodes that have restrictions on the internal connections between outer links, existing methods for node-disjoint paths search have trap problems and require time consuming iterative procedures. In this paper, we present a novel iteration-free method for finding a pair of node-disjoint paths considering asymmetric nodes. The proposed method includes a novel network transformation and a constraint-based path search. Through simulation, we confirm that the presented method can successfully find optimum node-disjoint paths without encountering trap problems, which implies that the method can support any number of asymmetric nodes and any type of asymmetric connections.