Scalable parallel computer architectures will require communications networks which are also scalable. The simplest, most scalable communication architecture involves only nearest neighbor and next nearest neighbor interconnection; however, it is not known to what extent such a network will prove a bottleneck for general purpose computing. Nimble proposes to develop a communications protocol for such a locally connected scalable processor which obeys an analog of the "superposition" principle of wave propagation in a linear medium. Such a superposable communications protocol should permit point-to-point interference-free communications, scale with the size of the processor, and degrade gracefully in latency and bandwidth with increasing congestion. A superposable messaging protocol should also make better use of the available computational resources than a fixed partitioning of the resources into computation and communication components.
