A STUDY OF NON BLOCKING MULTICAST SWITCHING-NETWORKS

This paper studies three-stage switching networks capable of routing p oint-to-multipoint connections. Strict-sense non blocking operation is addressed and, in particular, the necessary and sufficient condition for a three-stage switching network to be strictly non blocking when i t is offered point-to-multipoint traffic is derived. This condition is given as a function both of the minimum and the maximum number of net work outlets addressed by each connection. In this respect, this work extends the well known Clos' result, giving the necessary and sufficie nt condition for a three-stage switching network to be strictly non bl ocking when it is offered point-to-point traffic. The complexity of a three-stage network is lower than that of a crossbar of equal size onl y for small values of the maximum admissible fanout of the incoming co nnections.