An algorithm for waveband routing and wavelength assignment in hierarchical WDM mesh networks

Aggregation of wavelengths into wavebands is an attractive, cost-efficient way to facilitate switching and routing in optical networks. We study the waveband routing and wavelength assignment (WRWA) tasks in hierarchical WDM mesh networks with optical crossconnects that can route multiple granularity (wavelengths and wavebands) at the same time. We solve the waveband routing and wavelength assignment subproblems as a single problem, rather than separating them into two separate problems. We propose a waveband routing and wavelength assignment algorithm, which is designed to minimize the number of wavelength conversions. The algorithm is solved by using dynamic programming, sequentially on one lightpath request at a time. We comment on the WRWA performance under various traffic scenarios. Our results demonstrate a significant cost reduction compared to WDM mesh networks with a single granularity, i.e., without using wavebands.