Multicasting in generalized multistage interconnection networks

Multistage interconnection networks (MIN) are popular in switching and communication applications. It is also well known as a hypercube derived architecture, offering a fixed-degree alternative to hypercube for a large class of applications. Message routing strategy in MIN is well known, however, multicasting issues for MIN has not been considered. This paper formulates the multicasting problem for MIN. We demonstrate that reordering the dimensions in MIN can lead to traffic reduced multicasting. This leads to the formulation of optimality criteria in MIN multicast operation. Traffic optimum multicasting in MIN is shown as a NP-Complete problem. We present a polynomial time greedy heuristic to generate traffic reduced multicast in MIN. The greedy approach generates a locally optimum solution. Analytical study and simulation results are presented showing the traffic reduction that can be obtained using our approach over traditional linearly ordered dimensions approach.