Turn Prohibition Based Routing in Irregular Computer Networks

In this paper we study turn prohibition based multicast wormhole message routing in computer networks with irregular interconnection graphs. Routing is accomplished in two phases. When a topology change is detected the first phase of routing is executed. Here the network graph is analyzed and a set of turns to be prohibited to break all cycles in the channel dependency graph is created. The turns in this set are prohibited from use during the second routing phase in order to guarantee that channel dependency graph is free from cycles and that routing is deadlock-free. Turn prohibition based routing or TPBR, prohibits the use of at most 1/3 of all turns in the graph. In this paper turn prohibition based routing have been extended for multicast wormhole routing in irregular topologies. We assume that routers have capabilities for selectively replicating worms as they pass through the routers. Furthermore, we assume that each physical link has the resources to operate virtual channels in a time-multiplexed manner. The performance gain obtained by further extension of our routing model to multiple virtual channels has also been investigated. Our experimental simulation results are compared with those of tree-based up/down routing model.