Circulant-Graph-Based Fault-Tolerant Routing for All-Optical WDM LANs

High demands in data delivery latency and communication reliability encourage the use of fault-tolerance-enhanced all-optical WDM networks. Low latency is satisfied by setting up a direct lightpath between any communication pair to enable one-shot transmission. High reliability is met by establishing multiple disjoint lightpaths from the source to the destination. In this paper, we explore the fault-tolerance potential in circulant graphs, which offer good flexibility in the number of supported nodes and network connectivity. We propose a circulant-graph-based all-optical network architecture together with a fault-tolerant routing algorithm. Network resource utilization is analytically calculated and results show that increasing network connectivity helps reduce the required number of wavelengths for simultaneous all-node communications. A connection reliability model is developed combining both node and link failure effects. The reliability benefit obtained from the proposed algorithm grows almost linearly with network connectivity increase in a logarithmic scale.