为了克服异步传输模式(ATM)网络不确定时延和饱和非线性的影响,基于比例控制和滞后-超前控制方法研究可用比特率(ABR)服务流量控制器设计问题,给出了控制幅值约束和缓冲区容量约束下系统满足ABR流量控制要求的条件,提出了满足这些条件的比例控制器和滞后-超前控制器的设计方法。该方法能使ABR流量控制系统在网络传输时延不确定时,有效控制网络中瓶颈节点缓冲区的队列长度,同时能够及时响应ABR可用带宽的变化,从而避免拥塞和丢包的发生,使链路带宽得以充分利用。
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 lag-lead 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.