Improving the Performance of Regular Networks with Source Routin

Networks of workstations (NOWs) are becoming increas-ingly popular as a cost-effective alternative to parallel com-puters. In these machines, the network connects processors using irregular topologies, providing the wiring flexibility, scalability, and incremental expansion capability required in this environment. Also, when performance is the primary concern, these network products are being used to build large commodity clusters with regular topologies [IO]. In previous papers [3, 41, we have proposed the in-transit buffer mechanism to improve network performance, applying it to NOWs with irregular topology and source routing. This mechanism allows the use of minimal paths among all hosts, breaking cyclic dependencies between channels by storing and later re-injecting packets at some intermediate hosts. In this paper; we apply the in-transit buffer mechanism to regular networks with source routing in order to improve their performance. Also, two path selec-tion policies are evaluated. The Brst one will always choose the same minimal path from source to destination, whereas the second one will choose from different alternative mini-mal paths in a round-robin fashion. The evaluation results show that the overall network throughput can be doubled for large networks.