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  1. E. Nyberg, J. Virtamo and S. Aalto, An exact algorithm for calculating blocking probabilities in multicast networks, COST257, TD(99)26, 1999 (pdf)(bib)
    Abstract: The paper deals with tree-structured point-to-multipoint networks, where users from infinite user populations at the leaf nodes subscribe to a variety of channels, offered by one source. The users joining the network form dynamic multicast connections that share the network resources. An exact algorithm for calculating end-to-end call blocking probabilities for dynamic connections is devised for this multicast model. The algorithm is based on the well-known algorithm for calculating blocking probabilities in hierarchical multiservice access networks, where link occupancy distributions are alternately convolved and truncated. The resource sharing of multicast connections requires the modification of the algorithm by using a new type of convolution, the OR-convolution. The exact algorithm for end-to-end call blocking probabilities enables us to study the accuracy of earlier results based on Reduced Load Approximation. The model is further extended to include background traffic, allowing the analysis of networks carrying mixed traffic e.g. multicast and unicast traffic.