On the Configuration of Switch-Based Networks with Wormhole Routing

Abstract

In this paper we investigate the configuration of switches suitable for high performance communication, and propose communication schemes which exploit the structural strengths of that configuration. In switch-based networks, communication performance heavily depends on the configuration of switches and communication schemes for the networks. The deadlock problem caused by wormhole routing is another crucial factor affecting communication performance. Thus, we first evaluate several candidate configurations in terms of deadlock avoidance, scalability, flexibility, cost, and network properties (bandwidth, diameter, and average distance), and verify that the incomplete fat tree is the most promising configuration. Next, we show how to implement a routing algorithm and a unicast-based multicast algorithm on the incomplete fat tree configuration. The routing algorithm always finds a shortest path and fully utilizes network resources without using a routing tables. The multicast algorithm is optimal in that it is contention-free and requires a minimum number of communication steps.