Study of packet loss in a packet switched voice system

Abstract

A study is presented of the temporal behavior of packet loss on a voice-transmitted TDM time-division multiplexed link. The mean duration is given of blocking and nonblocking periods, the variance of blocking periods, and the expected packet. The loss rate within blocking periods is derived. These measures are extended to characterize the performance of packet loss at various rates. The results provide significant information on voice packet loss and can be directly applied to the design of packet-switched voice systems. The packet loss rate in a voice system changes slowly and has large fluctuations. This temporal behavior of packet loss, especially at high rates, is basically characterized by voice correlation and system capacity. Increasing the buffer size merely extends the nonblocking periods and thereby reduces the overall average packet-loss-rate. Once a blocking period occurs, however, the length of this period as well as the behavior of packet loss within the period becomes irrelevant to the buffer size. Based on this observation, a simple tool is developed to evaluate the boundary performance of packet loss at various rates; it is especially accurate at high rates. >