On Con guration of Switch-Based Networks with Wormhole Switching

As switch-based networks have become promising network platforms to build workstation clusters for high performance computing, many types of (expensive) switches have been developed to support high-speed communication. However, their communication performance heavily depends on the connguration of switches and the deadlock problem caused by wormhole switching is another crucial factor in eeciently utilizing network resources. Thus this paper investigates the best connguration and proposes the eecient communication schemes for the networks composed of currently developed switches. First, we evaluate several candidate conngurations in terms of deadlock avoidance, scalability, exibility, cost, and network properties (bandwidth, diameter, and average distance) and verify that the incomplete fat tree connguration is the most promising for switch-based networks with wormhole switching. Next, we show how to implement eeciently a routing algorithm and a unicast-based multicast algorithm on incomplete fat tree conngurations. The routing algorithm fully utilizes the network resources without the help of routing table and the multicast algorithm is optimal in that it is contention-free and requires the optimal number of communication steps.