Performance analysis of wavelength-routed optical networks with connection request retrials

Customer retrial is a common feature in practical service systems. This paper develops an analytical approach that incorporates reduced load analyses employing a retrial model, and investigates the effect of request retrials on the performance of wavelength-routed optical networks. The analytical approach can evaluate network performance in terms of request blocking probability, request loss probability, and total carried traffic. We analyze a representative network (NSFnet) with different retrial features and validate the proposed approach with simulation experiments. Analytical results indicate that the retrials increase the blocking rates of fresh request while decreasing the request loss rate, thus leading to a high total carried traffic in a network. For the routing schemes used in this work, the analytical results set a lower bound to the request loss probability and an upper bound to the total available traffic. The developed model allows performance analyses and service optimisation including customer retrials.