A technique to ensure reliability in a WDM optical backbone network with contemporary link failures

Contemporary link failures in a WDM optical network results in a very high value of call drop probability (CDP). In a backbone network, a link usually carries a huge amount of data and a low CDP is desirable. To address this issue, in this work, we propose a "path-based backup multiplexed survivable strategy", namely "dynamic recursive assignment of backup lightpath" (DRABLP). To ensure optimality in backup lightpath assignment, we have used a novel search algorithm, a variant of best first search. This algorithm is triggered at the occurrence of each failure and subsequent repair of a link. We have studied the performance of DRABLP w.r.t. CDP and new call blocking probability for varying network load. A comparison with another "path-based backup multiplexed survivable strategy", namely "without recursive assignment of backup Lightpath" (WORABLP), shows that DRABLP has smaller CDP than WORABLP when there are consecutive link failures within short span of time.