MCS: Buffered Clos-network switch with in-sequence packet forwarding

Multi-stage buffered Clos-network switches suffer from out-of-sequence packet forwarding. This paper proposes a three-stage memory memory memory (MMM) Clos-network switch, called the MCS switch, which provides in-sequence packet forwarding while maintaining high throughput. The proposed MCS switch adopts the oldest-cell-first selection for arbitrations at the first and second stages and an iterative matching scheme at the third-stage of the switch to provide in-sequence packet service. It keeps the properties of a buffered Clos-network switch, such as small configuration time and relaxed time synchronization among different switch modules and stages. The performance of the proposed switch is analyzed through computer simulation. Simulation results show that the performance of the proposed switch under both uniform and nonuniform traffic is comparable to that of a switch without in-sequence packet service.