Wavelength Division Multiplexing

In Wavelength Division Multiplexing so each light path can carry a huge amount of traffic and if end-user applications. Hence fault-tolerance path which carries traffic during normal operation is called as primary path. In case any failure occurs, the same traffic is rerouted on an alternative path that may be called as backup pat routing approach for establishing primary and backup paths. In order to establish the primary path, this approach uses load balancing in which link cost metrics are estimated based on the current load of the l backup path setup, the source calculates the blocking by sending a small fraction of probe packets along the existing paths. It then selects the optimal light path with the lowest blocking probability. This approach reduces the blocking probability and latency at the same time increases the throughput and channel.