ABSTRACT

SUMMARY Input buffered switches most efficiently use memory and switch bandwidth. With Virtual Output Queueing (VOQ), head-of-line blocking can be avoided, thus breaking the throughput barrier of 58.6%. In this paper a switch architecture based on VOQ is proposed, which offers deterministic and stochastic delay bounds for prioritized traffic. This is achieved by a hybrid static and dynamic arbitration scheme, which matches ports both by a precalculated schedule and realtime calculations. By using weighted dynamic arbitration algorithms 100% throughput with lowest delays under all admissible traffic can be achieved. An integrated global priority scheme allows the multiplexing of realtime and data traffic. Following the arbitration decision, a cell scheduler decides locally in the input ports upon the next connection from which a cell is forwarded. Cell scheduling based on earliest-deadline-first (EDF) is shown to perform similar to its behaviour in an output-queued switch.