A simple host deflection scheme for high-speed LANs using wormhole routing

Wormhole routing is a simple, low-cost switching scheme often used for supercomputer interconnections. It also has been applied to high-speed local area networks to support applications demanding high-data-rate communications, such as cluster computing. The drawback of wormhole routing is its low link efficiency caused by worm blocking. To overcome this blocking problem a timeout scheme was investigated by Hu and Kleinrock (see Proceedings of the 4th International Conference on Computer Communications and Networks, p. 584-93, Las Vegas, NV, 1995) using analytical modeling. We present timeout simulation results, showing the effect of packet size, propagation delay, and network size. Furthermore, a simple deflection scheme, which we call host deflection, is introduced and tested. This simple host deflection scheme requires only small modifications to the protocol and very little processing power from the switches, it improves the network throughput significantly.