A modular architecture for very large packet switches

The author proposes a modular architecture for very large packet switches, where each switch consists of a Batcher sorting network, a stack of binary trees, and a bundle of banyan networks. The modular architecture is a unification of the Batcher-banyan switch and the knockout switch, and it can be physically realized as an array of three-dimensional parallel processors. Switch modules are interconnected only at the outputs of multiplexers. The modularity implies less-stringent synchronization requirements and makes higher-speed implementation possible. Nonblocking and self-routing properties of Batcher-banyan switches are used to simplify the switch operation and to avoid the internal flow control problem. Also described is an extended ring reservation algorithm for contention resolution and output space extension. The proposed modular switch is intended to meet the needs of broadband telephone offices of all sizes. The author estimates that a modular switch with terabit capacity can be built with current VLSI technologies