Using a packet switch for circuit-switched traffic: A queueing system with periodic input traffic.

Packet switching is usually proposed for bursty data sources as a means to increase bandwidth utilization on shared transmission links. It can, however, also be used for nonbursty, stream traffic (e.g., voice without silence detection), avoiding the need for time slot scheduling and careful synchronization required with circuit switching. We analyze the effects of time-multiplexed, stream traffic on the performance of a store-and-forward packet switch. We find that there is a tradeoff between the amount of buffering in the switch and the probability that an existing circuit connection is disrupted. Substantially reducing the amount of buffering in the switch, however, results in only a small probability that an existing circuit will be disrupted during the length of its connection. For example, with a circuit switching frame of length 70 and 100% loading, reducing the buffer size from 69 to 23 results in only a 10(-6) circuit disruption probability.