e ATM networks have small cell size, high speed and little control overhead in cells. The two main ATM traffic management specifications are: Specification I.371 by the ITU-T Traffic Management Specification 4.0 by the ATM Forum. Tools for controlling congestion in packet-switched and frame relay networks are not appropriate for ATM networks because: ATM traffic is generally not amenable to flow control. For example, voice and video continue to generate and pump out cells, oblivious to a congested network state. The time in which cells are created and the time in which it is necessary for cells to be transmitted, particularly for real-time applications such as voice and video, is less than delays involved in propagation across a network. Therefore, feedback control is not viable because the time that it would take for messages on network OSS for Telecom Networks state to get back to a traffic management system, for the system to transmit instructions and for traffic to be re-routed according to those instructions would cause delays which degrade QoS. This would defeat the main purpose of traffic management. ATM networks enjoy a range of transmission speeds (kbps to Gbps). It is rare to find an implementation of a congestion control schema which accommodates such a wide range of speeds. Congestion control schema are generally suited to one or other end of the spectrum. While ATM networks accommodate a variety of transmission speeds, they are also used for a wide variety of applications. In particular, the diverse applications generate diverse traffic patterns. The most obvious different traffic patterns are the steady, high-rate flow of real-time applications versus data applications whose flow is not so constant. Traffic whose rate is not constant is said to be "bursty". Note that video compression can make bursty the real-time application of video. Owing to high switching speeds and high transmission speeds, an ATM network is generally fairly volatile even under normal operation. Designing a control scheme appro