Adaptive Multicast Routing Based on VP Trees

Two major routing policies were proposed to develop adaptive multicast routing (MST routing in 8]) algorithms in B-ISDN networks. One was to choose the route with the least number of links, and the other was to employ maximum free circuit routing. These methods suuer two major drawbacks: excessive amount of virtual path (VP) status messages to be transferred and performance degradation in asymmetric networks even ignoring the overhead and delay of transferring VP status information. This paper proposes a set of adaptive multicast routing algorithms based on the concept of VP trees. A VP tree which uses VPs dedicated to one-to-one communication as links in a multicast tree is an eecient approach to dimensioning a network allowing multicast communication. The proposed routing algorithms rst attempt to reserve resources of VPs in a default route predetermined with respect to the source and the set of destinations. Our simulation experiments show that the number of VP status messages transferred can be signiicantly reduced. For networks with equivalent bandwidth, the MST routing is able to generate more revenue if the VP status message transferring overhead is ignored. However, for asymmetric networks, which are more practical, the proposed adaptive routing algorithms can produce more revenue.