ALLNODE barrier synchronization network

This paper presents a proposed hardware solution using an existing multi-stage switching network for synchronizing N multiple processors at predetermined programmable barriers. The technique permits all N processors to access the network simultaneously and to perform synchronization in parallel using only several network cycles. The synchronization requires no additional network facilities, and consumes usually less than 5% of the bandwidth when merged onto the same multi-stage network that handles normal message traffic. The approach permits up to 2048 barriers, but can be expanded. The network is based on the Allnode Switch and Network concepts, a circuit-switching implementation, that permits a special barrier synchronization mode where all N processors are simultaneously attached to the network and can interact as if they were attached to a multi-drop bus