Support for Multiple Classes of Traffic in Multicomputer Routers

Emerging parallel real-time and multimedia applications broaden the range of performance requirements imposed on the inter-connection network. This communication typically consists of a mixture of diierent traac classes, where guaranteed packets require bounds on latency or throughput while good average performance suuces for the best-eeort traac. This paper investigates how multicomputer routers can capitalize on low-latency routing and switching techniques for best-eeort traac while still supporting guaranteed communication. Through simulation experiments, we show that certain architectural features are best-suited to particular performance requirements. Based on these results , the paper proposes and evaluates a router architecture that tailors low-level routing, switching, and ow-control policies to the unique needs of best-eeort and guaranteed traac. Careful selection of these policies , coupled with ne-grain arbitration between the classes, allows the guaranteed and best-eeort packets to share network bandwidth without sacriicing the performance of either class.