Nonblocking WDM multicast switching networks

With ever increasing demands on bandwidth from emerging bandwidth-intensive applications, such as web browsing, video conferencing, E-commerce, video-on-demand services, there has been an acute need for very high bandwidth transport network facilities. Optical networks are a promising candidate for this type of applications. At the same time, many bandwidth-intensive applications require multicast services for efficiency purposes. Multicast has been extensively studied in the parallel processing and electronic networking community, and has started to receive attention in the optical network community recently. In particular, as WDM (wavelength division muitiplexing) networks emerge, supporting WDM multicast becomes increasingly attractive. In this paper, we consider efficient designs of multicast-capable WDM switching networks, which are significantly different, and hence require non-trivial extensions from their electronic counterparts. We first discuss various multicast models in WDM networks, and analyze the nonblocking multicast capacity and network cost under these models. We then propose two methods to construct nonblocking multistage WDM networks to reduce the network cost