A performance model of a connection-oriented hypercube interconnection system

Abstract

Connection-oriented communication is becoming more and more important in the very high-speed (Gbps) communication environment. Under connection-oriented communication, all communication resources at the source (buffers, connection points), in the network (trunks), and at the destination (buffers, processing capacity) must be available before the start of a transmission. This paper presents an analytic model of a direct hypercube interconnection system operating in connection-oriented mode. Due to the high complexity of an exact model of such a system, a tractable approximate model is developed that exploits the system's symmetry to obtain a concise state description. We use our model to evaluate the performance of hypercube interconnection systems. We find that the contention for trunks is small compared to the contention for destination resources. A strategy of checking the resource availability of all waiting connection requests whenever a connection terminates, combined with random path selection, is shown to result in good load/delay characteristics. We further find that the system treats connections of all lengths equally. That is, counterintuitively, connections with shorter paths are not favored over connections with longer paths. We can thus conclude that in addition to good throughput/delay performance, random path selection is fair, and no other measures need be taken to ensure fairness.