Design of a Self-Timed VLSI Multicomputer Communication Controller,
William J. Dally, Paul Song · NASA STI/Recon Technical Report N · 1987
Abstract : We describe the design of the network design frame, (NDF), a self-timed routing chip for a message-passing concurrent computer. The NDF uses a partitioned data path, low-voltage output drivers, and a distributed token-passing arbiter to provide a bandwidth of 450Mbits/sec into the network. Wormhole routing and bidirectional virtual channels are used to provide low latency communications, less than micro seconds latency to deliver a 216 bit message across the diameter of a 1K node machine. To support concurrent software systems, the NDF provides two logical networks, one for user messages and one for system messages, that share the same set of physical wires. To facilitate the development of network nodes, the NDF is a design frame. The NDF circuitry is integrated into the pad frame of a chip leaving the center of the chip uncommitted.