For the design and control of ATM systems, it is important to have a performance model which produces reasonably accurate results over a wide range of parameters, since one major feature of ATM is that it can support many kinds of bursty traffic which have different communication speeds and time variations. We consider in this paper a heuristic approach which is based on the fluid approximation. In order to remove the possible inaccuracy of the fluid approximation in light to moderate traffic, we propose a G/D/l adjustment. The performance analysis predicts the buffer content and packet delay distributions which usually have stringent requirements. An infinite buffer is assumed in the analysis. However for ATM networks, where the buffer overflow probability is small, the infinite buffer model well approximates the finite buffer case. A number of numerical examples show that this heuristic approach is very accurate over a wide range of system parameters.
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