基于区分服务的队列调度算法研究

摘要

Weighted Round-Robin (WRR) and Deficit Weighted Round-Robin (DWRR) scheduling algorithm' s advantages and disadvantages in the architecture of DiffServ was discussed. And based on DWRR,a Deficit Weighed Round Robin plus (DWRR+) algorithm was presented in this paper. The algorithm dynamically set the maximum number of bytes for the current queue based on its length. The algorithm remedies the shortcoming of DWRR that can not meet the characteristics of delay under the premise of guaranteeing minimum bandwidths for different type of services. Extensive simulations were performed using NS-2. Simulation results demonstrate the validity of DWRR+, which can ensure the quality of service of different business to some extent.%文中分析了在区分服务(DiffServ)模型下的WRR和DWRR调度算法的优缺点,提出了一种DWRR的改进调度算法DWRR+.该算法根据当前队列中分组的长度动态设置一次服务中发送分组的最大字节数,既保证了低权值业务的延迟特性,又保证带宽分配相对的公平性,避免了低优先级队列可能长时间得不到服务的缺点,改善了DWRR算法不能很好满足业务的时延特性.使用NS-2网络仿真器进行算法性能评价,仿真结果表明DWRR+算法在保证输出带宽的前提下降低了延时,可以在一定程度上保证不同业务的服务质量.