Dynamic routing and wavelength assignment algorithms for multifiber WDM networks with many wavelengths

Abstract

We propose two dynamic RWA algorithms, the maximum-channel-path routing (MCPR) and the least utilized path routing (LUPR), which are suitable for multifiber WDM networks with many wavelengths available. Through our simulations on two network topologies, we compare the blocking probability of our proposed algorithms with the least-loaded routing (LLR) and the SPREAD, which has lower blocking probability than their predecessors. The proposed MCPR and the LUPR algorithms show lower blocking probability compared to the LLR algorithm. Our algorithms have higher blocking probability than SPREAD when the number of wavelengths per fiber is small, but they achieve more rapid improvement in blocking probability as the number of wavelengths per fiber increases. For sufficiently large number of wavelengths per fiber, MCPR yields blocking probability lower than SPREAD, and LUPR performs better than or similar to SPREAD, depending on the network topology. We believe that the reason is because MCPR and LUPR give preference to a path with more wavelengths available. Moreover, while the SPREAD algorithm considers all paths in the network to find the shortest path for an source-destination pair, our proposed algorithms search only the pre-determined paths, so their computational complexity is much less than that of SPREAD.