Accuracy of traffic modelling in fast packet switching

The problem of traffic modeling in fast packet switching is considered. The approach consists of modeling all layers of arrival process; that is, fluctuations of number of active calls, bursts, and packets are jointly considered. It is assumed that the channel is slotted and that packets have a fixed length. The multilayer Markov chain is defined and used to evaluate the mean waiting time of voice packets in statistical multiplexing. The final aim is to clarify when the complex structure of an information stream must be taken into account. The author presents several interim results which can be helpful in answering this question. In particular, he explains why some models are exact for small loads and others for large load.<>