Wavelength assignment in waveband switching networks with wavelength conversion

Waveband switching (WBS) wherein wavelengths are grouped into bands and switched as a single entity can reduce cost and complexity of switching nodes by minimizing the port count. In this paper, we study the effect of wavelength conversion on the performance of WBS networks with reconfigurable multi-granular optical cross-connects (MG-OXC) to satisfy online traffic. Since wavelength conversion is still expensive and can potentially increase the number of used ports in WBS networks, efficient usage of wavelength converters is of practical interest. We propose a novel heuristic algorithm, called waveband assignment with path-graph (WAPG), which takes efficient wavebanding and efficient usage of wavelength converters into consideration when satisfying new lightpath requests. We apply the WAPG algorithm in WBS networks with full, intra-band, or limited number of wavelength converters, and compare with the FirstFit and RandomFit algorithms. Our results indicate that the proposed algorithm performs significantly better in terms of the blocking probability as well as the number of used wavelength converters.