It is necessary that an ATM-based network be equipped with a congestion control mechanism to effectively and fairly allocate shared network resources such as transmission bandwidth and buffer capacity in a maiuler that provides satisfactory grade-of-service(GOS)for all network users with acceptable implementation costs.Traffic from users may need to be monitored and enforced to comply with traflic parameters that could be eshablished at the time of its admission to the ATM network.These parameters may include average and peak bit rates,and maximum burst Iengths.If the user does not conform to the parameters.actions must be taken for the violated traflic.The most common traffic enforcement method is the so-called"leaky bucket".Which is a simple open-loop control scheme,involving only local actions and no real-time coordination between network components.Depending on what enforcement action is taken and whether or nol there is a "shaping"buffer,four versions of the leaky bucket scheme are considered in this paper and their cell loss performance is compared in coniunction with a statistical multiplexer.Based on the best performing verslon,three architectures nave been proposed.Among mem.a novel algoritllm and its implementation method have been proposed to accommodate a large number of virtual channel connections on each incoming STS-3c channel.A VLSI chip(called a sequencer),containing aboul 200K CMOS transistors,has been designed to implement the architecture.
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