弹性分组环公平性分析及其改进算法

Improved fairness in resilient packet ring

弹性分组环(RPR)是基于分组的城域网发展的重要方向;公平性是RPR的关键技术之一;而传统的公平性概念并不适用于RPR,该文在首先定义适用于RPR的公平性概念的基础上,进一步分析了现今RPR协议草案中的公平算法,并针对此公平算法在非平衡流条件下的缺陷提出了改进方案-RPR节点流聚集(RPR-NIA)公平算法。仿真验证的结果表明,在非平衡流条件下,RPR-NIA公平算法在保证节点流聚集公平性的基础上能减轻振荡幅度,提高节点平均吞吐量,从而获得更高的带宽利用率;并且能够实现多拥塞节点条件下链路带宽分配的公平性。

The new requirements of metropolitan area networks (MAN) have resulted in the emergence of a new data transport technology, the resilient packet ring (RPR). The fairness is one of the key technologies in RPR. Since traditional definitions of fairness are not applicable to RPR, a fairness concept based upon the ingress aggregated flow was defined for RPR. The fairness algorithm described in the draft of the IEEE standard for RPR was then analyzed. Fairness problems with unbalanced data streams were overcome with an improved fairness algorithm named RPR-NIA which achieves better performance. Simulation results showed that the throughput of the oscillating node with the RPR-NIA algorithm was increased by 13.4% compared with the algorithm defined in the IEEE standard draft. The RPR-NIA algorithm can also implement fairness between nodes with multiple congested nodes in the ring.