Multicasting in WDM networks

Wavelength-division multiplexing (WDM) networks are believed to be a promising candidate to meet the explosive increase of bandwidth demand in the Internet. In this article, we survey the problems of and approaches to multicasting in WDM networks. In particular, we address the issues in the context of three types of WDM networks: broadcast-and-select, wavelength-routed, and optical burst-switched (OBS) WDM networks. Broadcast-and-select WDM networks are typically for WDM LANs¿MANs, and can be either single-hop or multihop. Various multicast scheduling algorithms (MSAs) are discussed for single-hop networks. For multihop networks, we discuss how channel sharing can be employed to effectively support multicast. In a wavelength-routed WDM network, supporting multicast leads to the multicast routing and wavelength assignment (MC-RWA) problem, which has been discussed for different scenarios, including sparse-splitting networks. We also discuss the problem of efficiently supporting multicast in optical burst-switched (OBS) networks, where the overheads due to control packets and guard bands need to considered.