Flow Control in ServerNet® Clusters

This paper investigates the performance implications of several end-to-end flow control protocols in clusters based on the ServerNet^® system-area network. The Static Window (SW) and Packet Pair (PP) flow control protocols are studied. Based on them, the Simplified Packet Pair (SPP) and the Alternating Static Window (ASW) protocols are defined. Previously, it has been proven that PP is stable for store-and-forward networks based on Rate Allocation Servers. The applicability of PP to wormhole-routing networks is studied. Simulation results for the performance characteristics are obtained and evaluated. It is shown that if high throughput is desired, ASW is the best method for controlling the average latency. On the other hand, if low throughput is acceptable, SPP can be applied to maintain low latencies.