ATM video signal multiplexer with congestion control function

Abstract ATM (asynchronous transfer mode) is a key technology in the construction of the broadband ISDN. In the ATM network, encoded video signals with burstiness are divided into short fixed length packets called cells, and can be transferred efficiently maintaining high quality by the statistical multiplexing of cells. However, in the congestion state, an appropriate congestion control is needed to avoid deterioration of transfer quality due to the loss of cells. This paper proposes a new congestion control scheme and evaluates characteristics of an ATM video signal multiplexer with the proposed congestion control function. In this paper, the amount of encoded video information per frame is approximated by the auto-regressive model, and the characteristics are evaluated by computer simulation. Particularly, the obtained circuit gain, the effect of congestion control and the optimum cell length are shown from the results of evaluation. Nearly double circuit gain can be obtained by the statistical multiplexing of cells and a throughput improvement of nearly 10% can be obtained by introducing the proposed congestion control in the multiplexing of cells.