Hybrid scheme for fault tolerant survivable WDM optical networks: An analytical approach with wavelength conversion

Dynamic lightpath protection in survivable WDM networks requires finding a pair of diverse routes (i.e., a primary route and a backup route that are link-disjoint) that form a cycle upon the arrival of a new connection request. This paper presents a hybrid adaptive survivability algorithm that combines the positive effects of restoration and protection. The overall goal of the proposed approach is to improve the restoration efficiency by providing tradeoffs between proactive protection and dynamic restoration. Experimental results simulated by ns-2 network simulator and analytical results for wavelength conversion case using MATLAB 7.3 are compared. In both the case hybrid scheme achieves significantly lower blocking probability, higher throughput, higher utilization and lower restoration than the conventional dynamic survivable techniques. The results obtained by approximate analytical model are almost identical with that of ns-2 simulated results.