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面向分组交换网络的模糊动态分布式队列调度

Fuzzy-Based Dynamic Distributed Queue Scheduling for Packet Switched Networks

  • 摘要: 解决分组交换系统的队列调度问题是拥塞控制的一个重要方面。为了通过使用预设参数对流量的不同服务质量需求实现一定的控制, 本文采用模糊逻辑决策方法进行队列调度。由于时变分组到达过程将影响网络状态和性能, 本文提出的模糊调度器充分考虑互联网流量的动态特性。定义了低、中、高三个优先级队列, 分组优先级的选择将影响队列的服务方式。在队列调度机制中, 模糊调度器不仅利用队列优先级, 同时也考虑分组丢失的敏感性以及队列限制。模拟显示模糊调度器更加适用于分组交换系统中互联网流量的动态特性。与优先级队列、先进先出队列以及加权公平队列相比, 模糊调度器的调度策略可以减少分组丢失, 提供良好的信道利用率并使报文延迟最小。

     

    Abstract: Addressing the problem of queue scheduling for the packet-switched system is a vital aspect of congestion control. In this paper, the fuzzy logic based decision method is adopted for queue scheduling in order to enforce some level of control for traffic of different quality of service requirements using predetermined values. The fuzzy scheduler proposed in this paper takes into account the dynamic nature of the Internet traffic with respect to its time-varying packet arrival process that affects the network states and performance. Three queues are defined, viz low, medium and high priority queues. The choice of prioritizing packets in皍ences how queues are served. The fuzzy scheduler not only utilizes queue priority in the queue scheduling scheme, but also considers packet drop susceptibility and queue limit. Through simulation it is shown that the fuzzy scheduler is more appropriate for the dynamic nature of Internet traffic in a packet-switched system as compared with some existing queue scheduling methods. Results show that the scheduling strategy of the proposed fuzzy scheduler reduces packet drop, provides good link utilization and minimizes queue delay as compared with the priority queuing (PQ), first-in-first-out (FIFO), and weighted fair queuing (WFQ).

     

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