Point-To-Multipoint Path Establishment Schemes To Support Multicasting In WDM Networks

Next generation Internet multimedia applications will increase the need for high throughput and low latency. Wavelength Division Multiplexing (WDM) optical networks have the potential for achieving these two goals by ooering unprecedented high bandwidth. One very important aspect of new Internet services is the support of multicasting. As such, support for multicasting in WDM networks becomes crucial if these networks were to play an eecient role in the next generation Internet. Multicasting in WDM networks supporting multimedia applications can be viewed as the process of taking a group communication request and selecting a multicast tree that satisses the quality of 1 2 service (QoS) requirements, in terms of bandwidth and end-to-end delay, of the underlying application. In this paper, we present a new class of low-cost, bounded-delay multicast heuristics for WDM networks. The heuristics use various techniques to establish a tree of semilightpaths between a source and a group of destination nodes. The unique feature of these heuristics is that they decouple the cost of establishing the multicast tree from the delay incurred by data transmission due to lightwave conversion and processing at intermediate nodes along the transmission path. INTRODUCTION The Next Generation Internet (NGI) technology will, for the most part, be driven by the increasing need for high throughput and low latency. Optical networks have the potential for achieving these two goals by ooering unprecedented bandwidth in a medium that is free from inductive and capacitive load-ings, thus relaxing the limitations imposed on the bandwidth-distance product 10, 15]. Optical bers may be used for transmitting terahertz signals in low attenuation passbands while maintaining low error rates and low sensitivity to noise 21, 11]. Although diierent types of photonic switching networks have been reported and demonstrated, Wavelength Division Multiplexing (WDM) has emerged as one of the most attractive approaches for data transfer in interconnection networks 5, 11, 7, 19]. WDM divides the optical ber link spectrum into several channels, each corresponding to a diierent wavelength 1. An incoming wavelength in one input port can be routed to one or more output ports. Due to electromagnetic interference, however, the same wavelength coming from two separate input ports cannot be routed to the same output port. In single-hop WDM networks, the optical layer provides a lightpath to the higher layers. A lightpath is an all-optical transmission path between a source and a destination which uses the same wavelength between the intermediate nodes …