Patent ID: 7424010

Claim:
An apparatus, comprising: a controller configured to establish a new multicast connection within a network without changing a path of an existing multicast connection within the network, the network having: an input stage comprising r 1 input switches, and at least n 1 inlet links for each of said r 1 input switches for a total of at least n 1 *r 1 inlet links in said input stage, an output stage comprising r 2 output switches, and at least n 2 outlet links for each of said r 2 output switches for a total of at least n 2 *r 2 outlet links in said output stage, and a middle stage comprising m middle switches, and each middle switch comprising a first internal link connected to each input switch for a total of at least r 1 first internal links, each middle switch further comprising a second internal link connected to each output switch for a total of at least r 2 second internal links, the new multicast connection from an inlet link from the at least n 1 *r 1 inlet links passes through at most s middle switches, and said new multicast connection further passes to at least a portion of the n 2 *r 2 outlet links from said at most s middle switches, where m≧s*MIN(n 1 ,n 2 ) and where s=2 when r 2 =[9,11], s=3 when r 2 =[25,48], s=4 when r 2 =[49,99], s=5 when r 2 =[100,154], s=6 when r 2 =[155,224], and s=7 when r 2 =[225,278].