Maximizing multicast throughput in WDM networks with tuning latencies using the virtual receiver concept

We consider the problem of supporting multipoint communication at the MAC l ayer of broadcast WDM networks. We first introduce the multicast throughput as the performance measure of interest and we show that it depends on two measures that have previously been considered in isolation, namely, the eff icient use of channel bandwidth and wavelength throughput. We then present a new technique for the transmission of multicast packets based on the conc ept of a virtual receiver, a set of physical receivers which behave identic ally in terms of tuning. We also demonstrate that the number of virtual rec eivers naturally captures the performance of the system in terms of multica st throughput. Consequently, we focus on the problem of optimally selecting the virtual receivers to maximize multicast throughput, and we prove that it is NP-complete. Finally, we present four heuristics of varying degree of complexity for obtaining a set of virtual receivers that provide near-opti mal performance in terms of multicast throughput.