Abstract: Active queue management is a focus of current research. Random Early Detection (RED) is one kind of classical queue management algorithms. Linear RED is simple and easy to calculate; however, when average queue size is near to the minimum and maximum threshold, the loss rate is unreasonable. After verifying the nonlinear character between average queue size and packet loss rate, an improved RED algorithm named JRED was presented. The simulation on NS2 shows that the average throughput is improved, and the packet loss rate is decreased. With the JRED algorithm, the stableness and reliability of network are enhanced.

Key words: queue management, Random Early Detection (RED), nonlinear, average queue size, average throughput, Network Simulator version 2 (NS2)

摘要： 主动队列管理是目前的研究热点，随机早期检测(RED)算法是一种经典的队列管理算法。线性RED算法虽然简单且容易计算，但队列位于最小阈值和最大阈值附近时的丢包概率都不太合理。在论证了平均队列长度和丢包概率间为非线性性质后，提出了一种改进非线性RED算法——JRED。利用NS2对改进的算法进行仿真，结果表明，JRED算法提高了平均吞吐量，降低了丢包概率，增强了网络稳定性和可靠性。

关键词: 队列管理, 随机早期检测, 非线性, 平均队列长度, 平均吞吐量, NS2