A multirate network is Wide Sense Non Blocking with a new routing algorithm classifying requests into large, load greater than 1/(1+p), and small groups, where B is the upper load bound of any given request and p=.left brkt-bot.1/B.right brkt-bot.. Where B is less than 31/32-.beta./4, substantially 2.beta.n(P+1)(B+p-1)/p2 center interconnection units are restricted for carrying large requests only. For all other B, substantially 2.beta.n center interconnection units are restricted. Using this routing algorithm, general multirate WSNB is guaranteed with substantially the lesser of 2f(p)+1+3.75.beta.n and 2n.beta.(P+1)(Bp+B+p-1)/p.sup.2 interconnection units where n is the number of inlets per input stage switch, .beta. is the ratio of load capacity of external links to the input and output stages, and the load capacity of the internal links connecting the center stage to the input and output stages. Where the network is a three-rate network then the center stage can be further reduced to 5n center interconnection units for .beta.=1. The center stage can be even further reduced to 3n center interconnection units if the network is a two-rate network for .beta.=1.