Patent ID: 6868084

Claim:
A network having a plurality of multicast connections, said network comprising: an input stage comprising r 1 input switches, and n 1 inlet links for each of said r 1 input switches; an output stage comprising r 2 output switches, and n 2 outlet links for each of said r 2 output switches; and a middle stage comprising m middle switches, and each middle switch comprising at least one link (hereinafter “first internal link”) connected to each input switch for a total of at least r 1 first internal links, each middle switch further comprising at least one link (hereinafter “second internal link”) connected to each output switch for a total of at least r 2 second internal links; said network further is always capable of setting up said multicast connection by never changing path of an existing multicast connection, and the network is hereinafter “strictly nonblocking network”, where m is a minimum of at least 2*n 1 +n 2 −1.