On the performance behavior of ATM end-stations

Shaping of traffic at its source is a prominent congestion control solution in ATM networks. The “leaky bucket” with a “cell spacer” is a very popular traffic shaping approach. By sizing the leaky bucket and spacer parameters, an end-station shapes its traffic to conform to a “good behavior” contract with the network. The leaky bucket delays the transmission of selected number of cells, while the spacer forces a minimum time-distance between transmitted cells. When a contracted transmission rate is close to the traffic generation rate by the end-station, this traffic stream will utilize most of the bandwidth available on its virtual connection. The high utilization of such a connection leads to large queues of frames and cells at the end-station, With high adverse consequences to the end-to-end delay and jitter. In this paper, based on the negotiated traffic parameters and source traffic characteristics, we study, through simulations, the contribution of the leaky bucket plus cell spacer subsystem to the delay and jitter in an end-station. We also study the distribution of the size of the burst of cells leaving the end-station and entering the network. Finally, we derive the theoretical upper bound for the size of bursts of cells