Routing and wavelength assignment in all-optical networks with multicast traffic

In this paper, we consider the Routing and Wavelength Assignment (RWA) problem in all-optical wavelength-routing networks with multicast traffic. The RWA problem has been proved NP-hard. Many researchers are working on this problem and many algorithms have been proposed to solve the RWA problem. However, most of these algorithms only consider unicast traffic, while with multicast traffic, the blocking probability becomes very high. The main problem here is that the duplicated information transmitted in the network will consume a large amount of bandwidth. To solve this problem, we propose two SMT (Steiner Minimum Tree) based algorithms. The basic idea is to establish the multicast connections using the Steiner Minimum Tree, such that the duplicated information transmitted in the network can be minimized. Numerical results illustrate that the SMT based algorithms can achieve remarkable performance under a hybrid traffic model, consisting of both unicast traffic and multicast traffic.