A Performance Study of Multicast Routing Algorithms for ATM Networks

This paper addresses the problem of multicast (i.e., point to multipoint) routing in ATM networks. In particular, formal experimental methods are used to evaluate the relative performance of three simple multicast routing algorithms on simple mesh-based networks, using call-level simulation. The performance study focuses on the scalability of multicast routing algorithms with respect to network size, the level of multicast traac on the network, and the size of multicast groups. Call blocking probability and links used per successful call are used as the primary performance metrics. The simulation results show that the choice of a multicast routing algorithm has a major impact on network performance. Shared link algorithms, which route multicast calls along common link channels whenever possible, are more eecient. These algorithms improve the overall call blocking performance, reduce the call blocking bias against large multicast groups, and scale much better with network size. However, the improved call blocking performance for multicast calls comes at the expense of increased call blocking for unicast calls.