Resource Aware Routing and Intelligent Wavelength Assignment for Cooperative Clustered OBS Networks

Burst loss is a critical issue in Optical Burst Switching (OBS) networks which restrains its deployment. This article presents a novel routing and wavelength assignment strategy for the Cooperative Clustered OBS (C2OBS) network architecture, to proactively avoid contention. In C2OBS, the network topology is divided into several manageable overlapping zones/clusters, with a Zone Head (ZH) node keeping an information base of zone resources. The ZH pre-computes a list of alternate k-shortest disjoint paths for every ingress-egress node pair within the zone. The ZH utilizes both the inferred knowledge about wavelength usage at the zone intermediate nodes and a novel poles apart heuristic for assigning wavelengths to incoming bursts. A route is selected among the pre-computed paths where the selected wavelength is available. As a result, traffic is balanced among the set of pre-computed routes, thus proactively reducing probability of contention. This strategy is called Resource Aware Routing (RAR) and Intelligent Wavelength Assignment (IWA).