摘要： 主动队列管理 (AQM)是网络中间节点通过一定的分组丢弃策略来达到较低排队时延和较高吞吐量的一种机制。已有多种AQM算法被提出，但绝大多数没有考虑较大的RTT(往返时间)对算法性能的影响。该文针对大RTT的网络环境，实现了一种基于控制理论中Dahlin算法的AQM机制并分析了系统的稳定性和参数选择的准则。仿真实验结果表明，该算法在RTT较大的情况下稳定性、响应速度和鲁棒性都优于随机早期检测(RED)算法和比例－积分(PI)算法。

关键词: 拥塞控制, Dahlin算法, 主动队列管理, 往返时间

Abstract: Active queue management (AQM) can maintain smaller queueing delay and higher throughput by the purposefully dropping the packets at the intermediate nodes. Several different AQM algorithms have been proposed. Almost all the existed algorithms neglect the impact on performance caused by large round-trip time (RTT). This paper proposes a new AQM mechanism based on Dahlin algorithm in control theory to restrict the negative impact on the queue stability caused by the large RTT. The simulation experimental results show that the integrated performance of the proposed algorithm is obviously superior to those of the existed schemes.

Key words: Congestion control, Dahlin algorithm, Active queue management, Round-trip time