Virtual source based multicast traffic routing in IP‐over‐WDM networks

Abstract

Wavelength‐division multiplexed (WDM) networks using wavelength‐routing are considered to be potential candidates for the next generation wide‐area backbone networks. At present, Internet Protocol (IP) is considered as de facto standard for transferring data in a wide‐area network. As WDM technology matures, there is a growing interest in integrated IP‐over‐WDM networks. Supporting multicasting in these networks poses a challenging topic. In IP multicast routing, only a subset of nodes may have multicast capability. The nodes that are not supporting multicast routing are by‐passed using IP tunneling concept. Because of IP tunneling, a node with optical splitting capability may not be considered while constructing a multicast tree. This results in poor bandwidth utilization. Some times, non‐delivery of data to some destinations may also happen. Hence, the IP multicast routing protocol need to consider the capabilities of the nodes. But, it may require some modifications to the existing IP multicast routing algorithms. We propose an approach, where nodes with splitting capability and wavelength conversion capability are connected and form a backbone. Hence, IP multicast routing algorithms need not consider the special capabilities of the nodes and these algorithms do not require any modifications. In multicast routing establishing a protection path is a difficult task, since the capabilities of nodes differ from each other. Using our approach it is possible to recover from a link or node failure. Also in a wide area network, delay involved in generating and establishing connections for multicast traffic is very high. In our approach, this delay is low, since it makes use of pre‐established connections (i.e., pre‐established backbone). The effectiveness of our proposed approach is demonstrated using extensive simulation experiments. The blocking performance of the proposed approach is also studied for dynamically arriving multicast sessions.