Blocking probabilities of two-layer statistically indistinguishable multicast streams

We study calculation of blocking probability for two-layer multicast streams assuming Poisson arrivals and exponential holding times, and that blocked calls are lost. Users may join and leave the multicast connections freely, thus creating dynamic multicast trees. We define the state space, and give a recursive algorithm for the special case where all multicast channels are statistically indistinguishable. Our recursive algorithm is linear with respect to the number of links and polynomial with respect to the number of channels. We give blocking probabilities for both layers for an example network, and devise upper and lower bounds for layer 2 blocking probability.