With the rapid development of Internet and the increasing demand for broad bandwidth, optical network becomes more and more popular due to its high speed and huge capacity. An optical fiber can carry several light wavelengths. By assigning these wavelengths to the transmitters/receivers of optical hops, the logical topology for a physical network can be defined. The main advantage of such architecture is its reconfigurability. However, determining the best wavelength assignment and flow assignment becomes an issue. Existing approaches addressing these problems, based on optimization techniques, are unsatisfactory with large networks because of the large number of constraints.; By specifically appointing a logical topology with good properties, the exponential constraints can be avoided and a good solution can be found with much less effort. Based on this idea, a genetic algorithm is proposed to solve the problem. The objective of this study is to investigate genetic algorithm's suitability for this logical design problem. To calculate the congestion, the Alternative Path Algorithm is introduced as the objective function. New crossover strategies like Sub-graph Crossover, Cluster Crossover and Random Crossover are introduced. Different test schemes are evaluated in this thesis.; The good-gene effect, chromosome contention, and dropping coverage ratio/protection ratio phenomenon raise lots of challenges in practice. But over 90% chance of getting the optimal solution for 9-node networks makes this algorithm very attractive for further study.
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