Survivable design in WDM mesh networks

Abstract

This dissertation addresses several important survivable design issues in WDM mesh net­ works. We first consider single link failure scenarios. To achieve both high efficiency in capac­ ity utilization and fast restoration are primary goals of survivable design in optical networks. Shared backup path protection has been shown to be efficient in terms of capacity utilization, due to the sharing of backup capacity. However, sharing of backup capacity also complicates the restoration process, and leads to slow recovery. Ring-type protection in mesh topology, on the other hand, has the advantage of fast restoration. The p-cycle scheme is the most efficient ring-type protection method in terms of capacity utilization. Recently, the concept of pre-cross-connected protection was proposed to increase the recovery speed of shared path protection. We overview these protection methods and discuss their failure recovery processes. The recovery time of these schemes are compared analytically. We formulate integer program­ ming optimization problems for three protection methods in static traffic scenario, considering wavelength continuity constraint. We investigate the effect of network connectivity on the per­ formance of capacity utilization of the methods by experimenting on topologies with different average nodal degrees. Dynamically provisioning connections, i.e. lightpaths are established on demand as connec­ tion requests arrive at the network and torn down when connections are terminated is becoming more important in backbone transport network. Survivable design for dynamic traffic using p-cycle technique has the potential to achieve both fast recovery and capacity efficiency. We develop a p-cycle based scheme to deal with dynamic traffic in WDM networks. We use a two-step approach. In first step, we find a set of p-cycles to cover the network and reserve