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The technology employed in fiber optic communication which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths of laser light is known as the wavelength-division multiplexing (WDM). In optical WDM networks, when maximum flow algorithms are used for the Routing and wavelength assignment (RWA) problem, it optimizes the network resource usage. The existing routing methods rarely consider the current network load when making the routing decision. In order to overcome the drawbacks of the existing RWA methods, an adaptive routing and wavelength assignment protocol is proposed which is based on maximum flow and load balancing. In this work, Routing and Wavelength assignment is proposed adaptively based on the type of reservation request. When a network handles an advance reservation request, the routing is done using our Max-flow algorithm and wavelength assignment is done using an advance reservation algorithm. When the network handles an immediate reservation request, routing is done using the traffic load on each link on the paths and wavelength assignment is done using an immediate reservation algorithm.

He has more than 28 years of teaching experience. His teaching and research areas include Wireless Communications and Routing algorithms. Currently he is working as Head (Monitoring & Evaluation) at State Directorate of Technical Education, Maharashtra State, on World Bank assisted Project,TEQIP-2 (Technical Education Quality Improvement Programme).

Wavelength Division Multiplexing (WDM) technology is employed in fiber-optic communication systems to multiplex optical carrier signals to a single optical fiber using different wavelengths. Fault tolerance is an important parameter in WDM networks. When a fault occurs the network requires a fault tolerance technique to repair the fault. In this paper, a new fault tolerance technique is proposed for the load balancing routing and wavelength assignment (RWA) problem. In RWA problem the fault protection issue is alienated to fault tolerant routing and fault tolerant wavelength assignment for traffic in WDM networks. The wavelength assignment is done using an advanced reservation algorithm. In routing, the primary path is set by applying max-flow load balancing technique. Then a backup path is computed for handling the link failures based on the class of request. The backup path is used for link restoration when primary path fails. Based on the class, we find the available bandwidth for backup paths. An auxiliary graph is constructed based upon the link cost for the backup path. No backup paths are required to be activated when a single link fails. This provides guarantee that the failed connections can be restored. By establishing the backup path, fault tolerance in routing and wavelength assignment is effective.