Performance Evaluation of 100 Gigabit Ethernet Switches under Bursty Traffic

Switch fabrics for 100 Gigabit Ethernet systems pose high demands in terms of delay and scalability. In this paper we analyze the performance of a Clos-based switch fabric under uniform and bursty traffic, and compare its performance to a crossbar-based switch design for benchmarking. In particular, we focus on a Clos-design using a Space-Memory-Memory (SMM) configuration, which has recently gained increased interest due to its reduced hardware complexity. The traffic between the input and the central modules is distributed in either a static, random or Desynchronized Static Round Robin (DSRR) fashion. Simulation results show that for uniform Bernoulli traffic, the DSRR scheme outperforms the others. Under bursty traffic, the DSRR scheme and the random scheme achieve similar performance. The static scheme performs the worst for both cases. Comparing the SMM design to an Output Queued crossbar switch only reveals a minor performance penalty, which can be compensated by the high scalability, robustness and low complexity of the Clos-based design for high speed switching systems.