Disaster-resilient lightpath routing in WDM optical networks

Optical network serves as a core network with huge capacity and a multitude of high-speed data transmission. Natural disasters and physical attacks showed significant impacts on the optical networks such as damages the network nodes and optical links. Network survivability attempts to provide uninterrupted services when network component ceases to function or malfunctioned either in the event of a disaster or due to human intervention. In this paper, two polynomial-time algorithms have been proposed to select an optimal pair of link-disjoint lightpaths between two network nodes such that (1) their minimum spatial distance (MSD) is maximized, and (2) the path length of the primary lightpath is minimized such that backup lightpath has some particular MSD from the primary lightpath while disregarding safe regions around the source and destination nodes. Through extensive simulations, it is shown that, in case of disaster event, the first algorithm (DPMMSD) computes the backup path with maximum survivability in case of multiple link failures of spatially close nodes, whereas second algorithm (CMMSD) computes the shortest backup lightpath while adhering to the target survivability requirements. DPMMSD, CMMSD and the benchmark EKSP enables the evaluation and comparison of the performance. EKSP computes more pairs hence takes more computing time whereas DPMMSD and CMMSD modestly discard the computation of self and repeating pairs, enabling quick computations.