Abstract: This paper proposes a novel RED algorithm based on multiple priorities namely Preferential Dynamic Threshold-RED(PDT-RED). It can adjust dynamically average queue length thresholds respect to packets’ priority and unused buffer space, and realize differentiated services. On the basis of PDT-RED, an optimized scheme ——OPDT-RED is presented. Compared with RED, OPDT-RED can reduce loss rates of packets with higher priority by 56%~62% and the average loss rates of all packets by 33%~41%. It is easy to implement, and satisfies higher buffer utilization.

Key words: congestion control, RED algorithm, queue management, priority, Internet

摘要： 提出一种基于多优先级的动态阈值RED算法(PDT-RED)。根据分组优先级和未使用的缓存空间动态调节平均队列阈值，实现对不同类型的分组采取不同的标记/丢弃概率的区分服务。为了提高缓存利用率，在该算法基础上提出优化算法(OPDT-RED)。模拟实验证明，与同类算法相比，OPDT-RED使高优先级的分组丢失率降低了56%~62%，平均分组丢失率降低了33%~41%，并且简单、易于实现，能提高缓存的利用率。

关键词: 拥塞控制, RED算法, 队列管理, 优先级, 因特网

CLC Number: 

• TP301.6