The benefits of wavelength interchange in WDM rings

We quantify the improvement in blocking performance from the use of wavelength-interchange in WDM Rings and their interconnection. We show that using wavelength-interchange in WDM rings can significantly improve (by factors of 100 to 10000) the “fairness” in wavelength assignment between the longer and the shorter paths. More importantly, we found that for larger interconnected WDM rings this improvement can be achieved by including wavelength-interchange capability in just 10 to 20% of the network nodes. Finally, we develop two analytical models, an accurate but complex overflow model and a less accurate but simpler asymptotic model, for calculating the blocking performance of WDM rings with no wavelength-interchange that use the “maximum reuse” algorithm for wavelength assignment