A New Cost Function to Solve RWA Problem in Wavelength Routed Optical Network Using Genetic Algorithms

Routing and Wavelength Assignment Problem in wavelength division multiplexed optical network is represented as an Integer Linear Program which is found to be NP-Complete. Our attention is devoted to such networks operating under wavelength continuity constraint, in which a lightpath must occupy the same wavelength on all the links it traverses. In setting up a lightpath, a route must be selected and a wavelength must be assigned to the lightpath. We have proposed ILP formulations for MaxRWA and MinRWA problems with a new cost function. The cost function is based on congestion with delay and hop-count is of secondary importance. Genetic Algorithms provide an attractive approach to compute sub-optimal solutions for the RWA problem. This paper discusses a genetic algorithm way of solving the RWA problem on standard networks such as ARPANET.