A router architecture for QoS capable clusters

Many web servers and database servers make efficient use of clustering from cost, scalability and availability standpoints. Existing cluster interconnects use switching schemes which minimize transmission latency but do not provide any guarantee on the delay (e.g., Wormhole switching). The variety of applications which are run on clusters mandate that the cluster interconnect be capable of handling both best effort and delay bound traffic. A new router architecture capable of providing soft guaranteed service using wormhole switching was proposed. An improved router model with preemption capabilities has also been proposed in literature. In this paper a detailed analysis of the hardware complexity of the preemptive router is presented and some architectural modifications to reduce the hardware complexity of the preemptive router are proposed. An interconnection network simulator has been developed to compare and analyze the performance characteristics of the proposed router architecture.