Connection Availability in WDM Mesh Networks with Multiple Failures

Wavelength division multiplexed (WDM) technology has revolutionized wide-area networks. As the amount of traffic carried is very large, any single failure can be catastrophic. Thus, survivability of a network that refers to a network´s capability to provide continuous service in the presence of failures has become crucial in such networks. Communication networks are usually designed to survive single failure. However, in large networks the occurrence of multiple concurrent failures cannot be neglected. Therefore, in this paper we study connection availability in WDM networks assuming failures of any multiplicity. Shared path protection (SPP) scheme is an efficient network recovery mechanism in terms of network resource utilization and in many related works the SPP scheme has been studied to solve a single failure problem. We apply SPP scheme and propose an analytical model for calculation of connection unavailability in WDM mesh networks with multiple failure assumption. We have evaluated our model by simulations and show that the connection unavailability obtained by simulations is very close to the theoretical value obtained by our algorithm, which proves the accuracy of our model