具有优先服务机制的嵌套式DRR算法

针对DRR算法在保证业务时延性能上的固有不足,该文提出了具有优先服务策略的嵌套式DRR算法,该算法对需要保证延时的业务类实施专门的服务策略,利用漏桶控制和虚令牌的分配机制,并改善服务队列的调度策略,在不增加算法复杂度的情况下,有效地减小了时延敏感业务队列中包的延迟。文章证明了算法在获得延时保证的同时,选择合适的参数,仍然能够维持调度算法的公平性。仿真结果表明算法对时延性能的改善是明显的。

A Prioritized Nested DRR Algorithm

As DRR fails to provide strong latency bound, in this paper, a new scheduling discipline named Prioritized Nested DRR (PNDRR) is presented, which introduces a token bucket with virtual allocated token quantum and changes the entering order of the scheduling list for the latency-critical flow. By using the scheme for the latency critical flow, delay of packet in latency critical queue is effectively diminished. In this paper, theoretical analyses prove that PN DRR results in a significant improvement in the latency bound of delay-sensitive traffic in comparison to nested DRR(NDRR) while preserves the good properties as the same relative fairness bound and the per-packet complexity of 0(1) as NDRR. Simulation results also support analysis.