排队策略对QoS影响的研究与仿真 摘 要：为了保证在拥塞情况下，利用队列机制提高视频业务的服务质量，本文主要针对QoS(服务质量)中Diff-Serv(区分服务)机制的原理、架构及实施过程进行了研究，并且使用网络仿真软件OPNET Modeler构建了Diff-Serv环境，进行了仿真试验。分别使用不同的排队机制进行实验，得出PQ(优先级队列)规则中，IP分组的丢包率比FIFO(先入先出队列)规则中的低。而在运用WFQ(加权公平队列)规则时，IP分组没有丢失。三种队列，从端到端延迟方面看，性能最好的是PQ，最差的是FIFO。
关键词：服务质量;区分服务;FIFO；PQ；WFQ
Research and Simulation of Queuing Strategies Influence on QoS
Abstract：In order to use the queue mechanism to improve the video quality of service under congestion circumstances. the text study the Diff-Serv (differentiated services) principle, architecture and implementation mechanism in QoS(Quality of Service), and use OPNET network simulation software OPNET Modeler to build the Diff-Serv environment and do some simulation Experiments. The experiments were carried out by using different queuing mechanism, and we can get the conclusion that IP packet loss rate in the PQ (priority queue) rules is lower than it in the FIFO (first in first out) rules. But ip packet is not missing in the use of WFQ (weighted fair queuing) rules. From end to end delay, the best performance is PQ, the worst is FIFO.
Key Words:Quality of Service; Diff-Serv; FIFO; PQ; WFQ
目 录
摘要 1
引言 1
1. 概述 2
1.1 研究的背景 2
1.2 QoS的研究现状 3
2. QoS综述 3
2.1 QoS中的参数设置 3
2.2 QoS的体系结构 3
2.3 QoS中两种服务类型的比较 4
2.4 Diff-Serv中队列策略机制 4
3. OPNET网络仿真平台 5
3.1 OPNET网络仿真简介 5
3.2 OPNET仿真平台简介 6
3.3 OPNET网络环境 6
3.4 OPNET编辑器简介 8
3.5 OPNET建模机制 12
4. 网络仿真模拟实验 13
4.1 网络仿真实验目的 13
4.2 网络模型设计 13
4.3 OPNET仿真实验 14
4.4 仿真实验及其结果分析 14
5.结束语 19
参考文献 19
致谢 20,3258