Distributive waveband assignment in multi-granular optical networks

To handle the challenge of increasing node size in wavelength routing networks (WRNs), waveband switching (WBS) is introduced to group multiple wavelengths together as a band or fiber and switch them using a single port whenever possible. Literature studies with the off-line traffic confirm that WBS can effectively reduce the port count and cost as well as control complexity. In the cases with online traffic, both the port reduction and call blocking probability should be considered due to the unknown traffic pattern and limited resources. In this work, we first analyze a reconfigurable switching architecture and the blocking probability in WBS networks. Based on the analysis, we then propose a novel dynamic graph-based waveband assignment algorithm in conjunction with adaptive routing. The proposed algorithm employs the ant optimization techniques to reduce ports and blocking probability in the network with online traffic in a distributed manner. Our simulation results show that our graph-based waveband assignment algorithm combined with the adaptive routing scheme can achieve the best performance when compared to other schemes. Our study also shows that even with limited resources, WBS can achieve port saving and an allowable blocking probability.