基于2自由度Smith预估器的ABR业务拥塞检测与控制

The Detection and Control of ABR Congestion Mechanism Using a Two Degree-of-Freedom Smith Predictor

针对在高速网络中,传播时延对二进制ABR(Available Bit Rate)业务网络流量控制的不利影响,提出了一个新颖的2自由度控制结构作为拥塞的判定机制.这种控制机制不仅能克服原标准明晰前向拥塞指示(EFCI)算法中因存在带磁滞环的非线性环节引起的大幅振荡,而且在较大时延情况下仍能保持很好的给定值响应和抗干扰性能,同时可简单直接地对流控系统进行设计和调节.仿真结果验证了该控制方案的优越性.

A new detecting/relieving congestion mechanism was presented by using a two degree-of freedom Smith predictor that was proposed for resolving the negative impact of binary available bit rate （ABR） flow control with large propagation delays in high-speed networks. This mechanism not only avoids self-oscillation caused by the nonlinear law with hysteresis loop in standard explicit forward congestion indication （EFCI） algorithm, but also decouples the disturbance response from the setpoint response with large delay. Moreover, it is simple and straightforward in the design and corporation of the performance of binary ABR flow control system. The superiority of the proposed method was demonstrated by the simulation results.