Non-blocking generalized three-stage switching networks

In this paper multicast three-stage multiple-link interconnection networks are considered. Each network stage is composed by full multicast switching elements connected to the switching elements of adjacent stages through h links, with h>1. For such networks, called generalized three-stage interconnection networks, the necessary and sufficient condition for strict sense non-blocking is presented. These results extend those currently available in literature for multicast networks only in case of single-link inter-stage connections. Moreover, it is also demonstrated that, in the worst case of unrestricted fanout, the complexity of a N×N multicast multi-link network can be limited to O(N5/3). Such a complexity is lower than that relevant to a crossbar network of the same size for N/h>182