Optimal wavelength allocation policy in a three-node all-optical WDM network

In this paper, we consider the problem of optimal dynamic wavelength allocation in all-optical WDM networks. We study a network topology consists of a 2-hop path with three nodes for two classes of traffic. Each class corresponds to different source-destination pair. For each class, call interarrival and holding times are exponentially distributed. The objective is to determine a wavelength allocation policy in order to maximize the weighted sum of the users in the network of different classes. The problem can be modelled as a Markov decision process and the policy iteration algorithm can be implemented to determine the optimal wavelength allocation policy. It has been shown numerically that for two classes of users, the optimal policy is of threshold type and monotonic. Simulation results show that optimal allocation policy significantly improves the system performance compared with that of complete sharing policy.