Wavelength routing and assignment in a survivable wavelength division multiplexing mesh network

All-optical networks with wavelength division multiplexing (WDM) capabilities are prime candidates for future wide-area backbone networks. The simplified processing and management of these very high bandwidth networks make them very attractive. A procedure of designing low cost WDM networks is the subject of this investigation. In the literature, this design problem has been referred to as the routing and wavelength assignment problem. Our proposed solution involves a three-step process that results in a low-cost design to satisfy a set of static point-to-point demands. Our strategy simultaneously addresses the problem of routing working traffic, determining backup paths for single node or single link failures, and assigning wavelengths to both working and restoration paths. An integer linear program is presented that formally defines the routing and wavelength assignment problem (RWA) being solved along with a simple heuristic procedure. In an empirical analysis, the heuristic procedure successfully solved realistically sized test cases in under 30 seconds on a Compaq AlphaStation. CPLEX 6.6.0 using default settings required over 1,000 times longer to obtain only slightly better solutions than those obtained by our new heuristic procedure.