The Advantages of Partitioning Multicast Transmissions in a Single-Hop Optical WDM Network*

In a single-hop WDM optical network, a straightforward approach to implementing multicasting is to schedule a single transmission to multiple destinations so that all of the destinations may receive the same transmission by tuning their receivers to the same channel at the same time. Although scheduling a single transmission in this manner reduces the amount of transmitter and channel resources being used, it may also place a burden on the receivers in the network. If all receivers do not become available at the same time, then some receivers may have to wait (and be idle) for significantly long periods of time before receiving the message. In this paper, we investigate methods for partitioning a multicast group into a number of smaller subgroups and for scheduling a separate transmission for each of these subgroups. We show that this approach more effectively conserves and balances the usage of transmitter and receiver resources in the network and may lead to significantly improved system performance over the conventional single-transmission multicast approach.