This paper addresses the problem of routing and wavelength assignment (RWA) of scheduled lightpath demands (SLDs) in wavelength routed optical networks with no wavelength converters. The objective is to minimize the number of wavelengths used. This problem has been shown to be NPcomplete so heuristic algorithms have been developed to solve it suboptimally. Suggested is a tabu search algorithm along with two simple and fast greedy algorithms for the RWA SLD problem. We compare the proposed

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... thms with an existing tabu search algorithm for the same problem and with lower bounds derived in this paper. Results indicate that the suggested algorithms not only yield solutions superior in quality to those obtained by the existing algorithm, but have drastically shorter execution times.