基于微分先行PI的主动队列管理算法

主动队列管理(AQM)作为一种重要的IP层拥塞控制策略，对于提高Internet的服务质量起到了关键性的作用。简要介绍了AQM算法的研究现状和AQM中的PI算法，依据TCP拥塞控制策略基于数据包丢弃的窗口变化机制，设计了一种基于微分先行PI的主动队列管理算法，该算法依据路由器中队列长度的变化采用一定的微分校正原则，实时调整进入该路由器数据包的丢弃概率，使路由器中的队列长度能够稳定在参考值附近。仿真结果表明，该算法与PI算法相比具有更小的超调量，可以明显的加快收敛的速度，从而使Internet的服务质量有更大程度的提高。

Active queue management algorithm based on differential-before-PI

Active Queue Management(AQM) plays an important role in congestion control of IP layer. It is vital for the improvement of QoS. The status of AQM and PI algorithm was presented. Then,an Differential-before-PI Algorithm was designed,based on the strategy of TCP congestion control. This algorithm used differential to adjust the rate of dropping tail,according to the alter of queue. In this way the length of the queue could stabilitate at the reference value. Simulation results have shown that,compared to general PI,Differential-before-PI Algorithm can not only eliminate collision,but also be able to speed up the queue convergence,thereby improve the QoS of Internet.