摘要： 提出了一种用于共享缓存分组交换设备的最佳阈值Pushout 的缓存管理策略（OTP）。在这个策略中，缓存区采用共享的方式，而每个输出端口分组调度采用Pushout 策略。OTP 策略的主要思想是将输出端口按照其队列长度分为活跃和非活跃端口，根据队列长度与端口的活跃程度决定分组的接纳或丢弃。仿真结果表明，OTP 策略在多个输出队列的情况下具有较好的公平性和鲁棒性，同时在丢包率方面，OTP 策略的分组丢失率接近于SP（Selection Pushout）策略。

关键词: 缓存管理；交换系统；Pushout 策略；分组丢失率

Abstract: This paper proposes an optimal thresholds pushout (OTP) policy for sharing buffer management. The OTP is composed with per-port pushout and sharing buffer thresholds. The queues are divided to two types according to their length. The queues whose lengths are larger than fair buffer are active ports; otherwise the queues are inactive ports. If the buffer threshold is smaller than a certain value, the packets destined to all ports are accepted, otherwise packets are accepted or dropped according to the ports type. Simulation result shows OTP policy has fairness and robustness;on the other hand the packet loss probability of OTP is very close to SP.

Key words: Buffer management; Switch system; Pushout policy; Packet loss probability