ATM network modeung and design for bursty traffic

Some of the services to be carried over ATM networks, notably high-speed data communications, are likely to generate traffic which is highly bursty, ie. characterized by long streams of cells destined for a common address. A number of possible models for this traffic are described and its effects on cell delay and buffer requirements in the network are analyzed. lt is argued that buffers of length at least several hundred cells may be required at each switch output to provide acceptable cell loss rates. The results are shown to be quite sensitive to the assumed traffic model suggesting that accurate models will be critical to network design. While traffic at the edge of the network can be modeled by assuming certain behavior for the traffic sources, it is not clear how the characteristics of traffic are altered as it moves through the network. A simulation study to determine whether traffic becomes more or less bursty as itprogresses through the network has been undertaken; the resulls presented here indicate that the average burstiness decreases, suggesting tha4 at a given occupancy, lower delay and cell loss be expected from switches at the interior of the network than from those at the edges. Such information will be of considerable inportance for the designers of future ATM networks.