Access flow control algorithms in broadband networks

The authors present and analyze an access flow control algorithm which is applied at the access nodes to the network, specifically, at the input voice and video multiplexers. The algorithm uses a control signal that is proportional to the multiplexer congestion level to throttle the peak bit rate of the input arrival process. The algorithm comprises a continuous type of control rather than the conventional ON/OFF control type. To achieve this, two congestion thresholds (K1, K2) are used to limit the number of cells in the multiplexer buffers. The threshold levels are determined by required quality of service. The authors analyze the resulting quasi-birth-death queueing process for the video-buffer multiplexer. Performance analysis parameters such as the blocking probability and the mean number of bits per sample are presented to evaluated the quality of the video traffic