HP Labs Technical Reports

Analysis of Different Routing Strategies Under Bursty Traffic

Kotov, Vadim; Cherkasova, Ludmila; Rokicki, Tomas; Davis, Al; Robinson, Ian N.

HPL-94-92

Keyword(s):

Abstract: Deterministic routing strategies are cheap and fast to implement but suffer from increased message latency due to contention for resources in a packet switching fabric. Adaptive routing strategies are inherently more complex which may result in slower routing. Our goal is to investigate the trade-offs involved in using different routing strategies. This paper presents the results of a simulation study designed to answer this question for realistic bursty traffic workloads. In particular we compare deterministic and two forms of adaptive strategies and describe their effects on message latency and fabric throughput. Our results indicate that limited levels of adaptivity reduce message latency for bursty traffic loads but also delay the effects of flow control, thus leading to the possibility of fabric saturation.

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