A New Hierarchical Waveband Assignment Algorithm for Multi-Granular Optical Networks

In the wavelength routing networks (WRNs), one of the major challenges is the dramatic increase of node size and complexity. As an alternative solution, waveband switching (WBS) is introduced to group multiple wavelengths together as a band or fiber and switch them using a single port whenever possible. The WBS efficiency is defined as the ratio between the ports required under the WBS networks and the WRNs. In this paper, we illustrate that the WBS efficiency can be influenced by factors such as bypass-traffic, node-degree, and the overlapping between routing paths. We then propose a new Hierarchical Waveband Assignment (HWA) scheme while taking these factors into consideration to efficiently group the traffic in multi-granular optical networks. Our simulation shows that HWA provides a significant improvement over an existing WBS algorithm which offers near-optimal performance in terms of port number.