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PI(proportional integral)主动队列管理机制是应用控制理论中的比例积分控制器设计的主动队列管理机制,其性能优于RED(random early detection)算法,能有效地消除稳态误差.但PI算法默认参数在目标队列长度较小情况下收敛速度较慢;而参数整定上的试凑法,无法同时保障系统的瞬态和稳态性能.研究拥塞产生的原因及其表现形式,提出一种基于报文到达速率的PI算法(Rate based Proportional and Integral,RPI).它根据报文到达速率和队列长度,即拥塞瞬间状况和持续状况计算出合适的丢弃率.通过NS2模拟表明,相对于PI,RPI具有更快的收敛速度和更小的队列抖动.
PI (proportional integral) is an active queue management mechanism designed by PI controller in application control theory, whose performance is better than RED (random early detection) algorithm, which can effectively eliminate the steady-state error.But the PI algorithm default The parameter converges slowly when the target queue length is small, while the trial and error method for parameter tuning can not guarantee the transient and steady-state performance of the system at the same time.This paper studies the causes of congestion and its manifestations, Rate based Proportional and Integral (RPI) algorithm, which calculates the appropriate discard rate according to the packet arrival rate and queue length, ie, the instantaneous state of congestion and the state of persistence.The NS2 simulation shows that, compared with PI, RPI Have faster convergence speed and smaller queue jitter.