Traffic Analysis of a Token Ring PBX

A new approximation is described for the calculation of the transmission delay distribution experienced by voice subscribers connected to a token ring PBX. Together with simulation, the new technique is used to explore the dependence of delays to transmission on ring latency, voice packet length, and number of active subscribers for a 20 Mbit/s ring. Transmission delays are found to be relatively insensitive to the exact values of ring latency and voice packet length for the systems studied. The overall time between the generation and replay of speech samples is determined primarily by the voice packet length, and the use of short packets is recommended.