A new design for wide-sense nonblocking multicast switching networks

In this paper, we propose a new design for a wide- sense nonblocking multicast switching network, which has many comparable properties to a strictly nonblocking Clos permutation network. For a newly designed four-stage N × N multicast network, its hardware cost, in terms of the number of crosspoints, is about 2(3 + 2√2)N^3/2 = 11.66N^3/2, which is only a small constant factor higher than that of a three-stage nonblocking permutation network, and is lower than the O(N^3/2(log N/ log log N)) hardware cost of the well-known three-stage wide-sense nonblocking multicast network. In addition, the proposed four-stage nonblocking multicast network has a very simple routing algorithm with sublinear time complexity, and does not require multicast capability for the switch modules in the input stage.