Abstract
In this thesis we propose a new rate-based flow control scheme for best-effort (ABR) traffics in ATM networks. This new scheme belongs to the reactive class o fflow control. Basically its operaton is based on simple 'stop' and 'start' signals sent from the downstream switch to upstream switches. In previously proposed flow control schemes, when congestion occurs, the congestion node sends 'stop' signals to all sources to request the sources to stop transmission or reduce the transmission rates. In our scheme we introduce mediate servers in the networks. When congestion occurs we do not require all sources to stop transmission or reduce the transmission rates immediately. In some cases it does not request any source to stop transmission or reduce the transmission rates. It will require all sources to stop transmission or reduce the transmission rates only in severe congestion condition. The performance measures presented in this thesis include cell loss probability, number of received cells by destination in fixed interval, and the overhead due to the control message. We also investigate the effects of the duraton of high transmission rates, the distance between congestion node and the mediate sever, and buffer size of the mediate server.