Input queued switches for variable length packets: analysis for Poisson and self-similar traffic

Abstract

We consider nonblocking, variable length packet switches where packet lengths and interarrival times have continuous distributions as is applicable in IP networks. A general throughput-delay model for Poisson and self-similar packet arrivals of eponential lengths to a single stage M× N switch with infinite and finite buffers is obtained. Analytical results are compared against simulation results on traces statistically similar to Bellcore traces. Tradeoffs between fixed packet length virtual output queued (VOQ) switches and variable length FIFO-combined input/output queued (CIOQ) switches with speedup and parallelism (multiple switching planes) are also studied. Analysis shows that a parallelism of four achieves 99.9% throughput. We also analyze the effect of traffic asymmetries and hotspots.