Considerations of periodic traffic in packet switching

The basic model of packet switching based on a self-routing interconnection network is described. The theory of periodic contention is reviewed, showing that a broadband switch is nonblocking for the periodic traffic type if it is fast enough to avoid the phenomenon of persistent blocking, where an input buffer consistently transmits fewer packets than it is receiving. The necessary and sufficient switch rate for avoiding persistent blocking is determined. This rate turns out to be a more stringent requirement than if the traffic pattern had been Poisson, a usual assumption