Broadcast Methods in the Multiswitch Point-to-Point Network

The Multiswitch project at Purdue University is investigating broadcast techniques for use in point-to-point networks. This paper analyzes four techniques for delivery of a broadcast message to all processors in a network. The current Multi-switch prototype network uses one of these techniques, called Flooding with Duplicate Discard (FDD). FDD is attractive because it provides high reliability of delivery of the broadcast message to all processors while requiring a relatively low number of packets. In FDD, the number of packets required to complete a broadcast is a linear function of the number of communication links and processors in the network, independent of the source of the broadcast. Each FDD broadcast traverses a source tree, a tree rooted at the source of each broadcast containing paths with minimum delay to all processors in the network. The source tree for a broadcast is not configured prior to the broadcast. An FDD broadcast message carries a unique identifier that must be held in a cache on each processor, but, for most networks, the identifier need not be held for long periods of time. An extension to FDD allows for efficient implementation of another broadcasting technique, source-based forwarding.