ABR flow control for asynchronous transfer mode networks using proportional and lag-lead controllers

Available bit rate(ABR) flow control systems in asynchronous transfer mode(ATM) networks experienie uncertain delays and saturation nonlinear.An ABR flow controller was designed based on a proportional control scheme and a lag-lead control scheme.Sufficient conditions are given which guarantee that the ABR flow control requirements can be met with control amplitude limitations and buffer occupancy limitations.Design methods for the proportional controller and the laglead controller were developed to satisfy the sufficient conditions.The resulting ABR flow control system effectively controls the buffer level of the bottleneck node and quickly responds to variations of the ABR bandwidth for uncertain transmission delays,so congestion and packet loss are avoided and the network utilization is improved.