A Practical Approach for Routing and Wavelength Assignment in Large Wavelength-Routed Optical Networks

We consider large optical networks in which nodes employ wavelength-routing switches which enable the establishment of wavelength-division-multiplexed (WDM) channels, called lightpaths, between node pairs. We propose a practical approach to solve routing and wavelength assignment (RWA) of lightpaths in such networks. A large RWA problem is partitioned into several smaller subproblems, each of which may be solved independently and eeciently using well-known approximation techniques. A multicommodity ow formulation combined with random-ized rounding is employed to calculate the routes for lightpaths. Wavelength assignments for lightpaths are performed based on graph-coloring techniques. Representative numerical examples indicate the accuracy of our algorithms.