A Unifying Approach to Determine the Necessary and Sufficient Conditions for Nonblocking Multicast Three-Stage Clos Networks

A Unifying Approach to Determine the Necessary and Sufficient Conditions for Nonblocking Multicast Three-Stage Clos Networks The three-stage Clos network is the most-studied switching network. However, exact conditions on the strictly nonblocking multicast three-stage Clos network under various models are difficult to get, due to the messy detail and because each case employs a different argument. Hwang and Liaw made the latest attempt, and pointed out errors in previous attempts. However, they made errors, too. In this paper, we propose a unifying approach to study those models systematically (which also applies to some wide-sense nonblocking networks). We also propose a new routing algorithm and use the unifying approach to derive a necessary and sufficient condition for wide-sense nonblocking.