Blocking of dynamic multicast connections

Multicast connections have a bandwidth saving nature. This means that a mul ticast connection - in taking the form of a tree with streams merging at th e nodes - requires much less capacity from the network links than a bunch o f separate point-to-point connections providing the same connectivity. In t his paper, we consider dynamic multicast connections that can be used to mo del, for example, TV or radio delivery on a telecommunications network, suc h as an ATM network with virtual circuits. We show how to calculate the blo cking probabilities of requests to join such a tree. First, we consider the blocking probabilities occurring in a single link. The resulting model is able to capture heterogeneous capacity requirements for different multicast channels. Then we extend the results to a whole network using the reduced load approximation. The accuracy of the approximation method is studied by simulations.