Performance of TCP Traffic and ATM Feedback Congestion Control Mechanisms

This paper presents a performance investigation of TCP traffic carried over ATM networks when feedback congestion control is exercised at the ATM layer. Two feedback congestion control schemes are investigated: the threshold feedback scheme and the optimal feedback scheme. Both schemes ensure a lossless operation so that TCP retransmissions are triggered by timer expirations. The focus of this study is the effective throughput experienced by the end users, when the efffect of retransmissions is taken into account. The effective throughput of these schemes as well as of the early packet discard control mechanism is obtained by means of simulation, and the results are compared to the case in which no congestion control is exercised at the ATM layer.