Effective Wavelength Assignment Algorithms for Optimizing Design Costs in SONET/WDM Rings

In high-speed wavelength-division-multiplexed synchronous optical network (SONET) ring networks, the terminal equipment costs associated with electronic multiplexing can be predominantly high. Placing a wavelength add–drop multiplexer (WADM) at each network node allows certain wavelengths to optically bypass the node without being electronically terminated. This approach can effectively reduce the total equipment cost if connections and channels are appropriately assigned in traffic grooming. In this paper, we present a series of wavelength optimization and wavelength assignment algorithms with the objective to optimize the number of required SONET add–drop multiplexers and yet minimizes the number of wavelengths in both unidirectional and bidirectional rings under an arbitrary grooming factor. In our analysis, we have considered both uniform and general nonuniform all-to-all network traffic. As a simple model for realistic traffic patterns, a special case of nonuniform traffic, distance-dependent traffic, is analyzed in detail. Significant ADM savings are observed for different traffic scenarios using our proposed algorithms.