The Chaos router

The Chaos router, a randomizing, nonminimal adaptive packet router is introduced. Adaptive routers allow messages to dynamically select paths, depending on network traffic, and bypass congested nodes. This flexibility contrasts with oblivious packet routers where the path of a packet is statically determined at the source node. A key advancement of the Chaos router over previous nonminimal routers is the use of randomization to eliminate the need for livelock protection. This simplifies adaptive routing to be of approximately the same complexity along the critical decision path as an oblivious router. The primary cost is that the Chaos router is probabilistically livelock free rather than being deterministically livelock free, but evidence is presented implying that these are equivalent in practice. The principal advantage is excellent performance for nonuniform traffic patterns. The Chaos router is described, it is shown to be deadlock free and probabilistically livelock free, and performance results are presented for a variety of work loads