K Pairs of Disjoint Paths Algorithm for Protection in WDM Optical Networks

Survivable Routing in Wavelength Division Multiplexing (WDM) optical networks has been proven to be NP-hard problem. There is a trade-off between the computational time and the optimality of solutions in existing approaches to the problem. Existing heuristic approaches purely based the graph algorithms are efficient in computational time but do not offer optimal solutions and may fail in some cases even when a solution exists. Meanwhile, the Integer Linear Programming (ILP) models offer optimal solutions but are intractable even with moderate scale networks. In this paper, we introduce a new algorithm for finding K pairs of disjoint paths which are employed as K candidate pairs for each connection in the ILP models. We introduce an ILP model for dedicated path protection in which the number of decision variables is mainly dependant on traffic requests and the constant K, not on the network size.