Broadcast/switching apparatus for executing broadcast/multi-cast

Abstract

A broadcast/switching apparatus makes input port to output port connections on a requested basis quickly and dynamically in a standard mode from any one of the input ports to any one of the output ports, in a multi-cast mode from any one of the input ports to a fixed number of subsets of multiple output ports simultaneously, or in a broadcast mode from any one of the input ports to all output ports simultaneously, using a new asynchronous approach to resolve either broadcast or multi-cast contention among input ports. The normal mode of the broadcast/switch apparatus requires absolutely no synchronization among any of the input and output ports which interface to the apparatus. The broadcast/switch apparatus also incorporates a new accept protocol that enables a positive feedback indication to be returned to the sender of a multi-cast or broadcast operation to inform it that the multi-cast or broadcast transmission was correctly received by all elements involved in the multi-cast or broadcast. The broadcast/switch is completely void of centrally controlled clocking and data buffering. Data which traverses the switch encounters only three gate delays--on-chip receiver, mux, and off-chip driver. Contention is detected and resolved on chip. Each broadcast/switch port interface requires several parallel data lines plus four control lines.