Nonblocking properties of interconnection switching networks

Self-routing interconnection networks with their low processing-overhead delay and decentralized routing, are an attractive option for switching fabrics in high speed networks. These interconnection networks, however, realize only a subset of all possible input-output permutations in a non-blocking fashion. The non-blocking property of these networks is an extensively studied area in interconnection network theory field and efficient algorithms exist to check if any given permutation is passable by such networks without blocking. One of the most common interconnection network structures is the inverse omega network and is topologically equivalent to the reverse banyan network. The authors show how to check the passability by the inverse omega network of any given connection set and list some of the very general patterns passable by this network. They also show that the concentrate operation passable by the inverse omega network is just a special case of the more general alternate sequence operation that they show as being passable. These non-blocking properties will be useful for cell routing in switches built with blocking networks in parallel or in cascade.<>