Optik ağlarda dalgaboyu dönüştüren düğümlerin seyrek konuşlandırması için bir tabu araştırma algoritması

ABSTRACTA TABU SEARCH ALGORITHM FORSPARSE PLACEMENT OF WAVELENGTHCONVERTING NODES IN OPTICALNETWORKSNamık SengezerşM.S. in Electrical and Electronics EngineeringSupervisor: Asst. Prof. Dr. Ezhan KaraşansSeptember 2004All-optical Wavelength Division Multiplexing networks, providing extremelylarge bandwidths, are among the most promising solutions for the increasingneed for high-speed data transport. In all-optical networks, data is transmittedsolely in the optical domain along lightpaths from source to destination withoutbeing converted into the electronic form, and each lightpath is restricted to usethe same wavelength on all the links along its path. This restriction is known asthe wavelength continuity constraint. Optical wavelength conversion can increasethe performance and capacity of optical networks by removing this restrictionand relaxing the wavelength continuity constraint. However, optical wavelengthconversion is a difficult and expensive technology. In this study, we analyze theproblem of placing limited number of wavelength converting nodes in a multi-fiber network with static traffic demands. Optimum placement of wavelengthconverting nodes is an NP-complete problem. We propose a tabu search basedheuristic algorithm for this problem. The objective of the algorithm is to achievethe performance of full wavelength conversion in terms of minimizing the totaliiinumber of fibers used in the network by placing minimum number of wavelengthconverting nodes. Numerical results comparing the performance of the algorithmwith the optimum solutions are presented. The proposed algorithm gives quitesatisfactory results, it also has a relatively low computational complexity makingit applicable to large scale networks.Keywords: Wavelength Division Multiplexing Networks, Wavelength Converters,Converter Placement, Tabu Searchiv