【作者】 黄超；

【导师】 刘琼； 江湧；

【作者基本信息】 华南理工大学 ， 软件工程（专业学位）， 2016， 硕士

【摘要】 为了应对网络规模急速膨胀和用户流量日益增大,网络设备不断扩展功能以满足需求。控制与转发一体化的传统网络架构不堪重负,难以满足各种应用服务。为解决这些问题,世界各国都在致力未来网络的研究。在众多研究中,逻辑控制与数据转发分离的架构引起了广泛关注,SDN(Software Defined Network,软件定义网络)的概念便这样提出。SDN的思想是将控制层与转发层分离,其中控制逻辑部署在控制器上,交换机在控制器指导下进行数据转发,简化了交换机的功能,同时控制逻辑的集中部署也实现了网络的灵活配置。SDN控制器为所有路径转发建立流表,只有依据真实的全网链路状态才能保证建立的路径最优,因此网络链路状态的监测尤为重要。本文依托于实验室项目“基于SDN的多路径网络流优化关键技术研究”,该研究旨在为当前业务选择和维护一条最优路径。本文所做的工作就是设计一套能够客观准确的测量网络链路性能的系统并实现,为控制器决策最优路径提供可靠依据。本系统中包括对控制器的设计、交换机的设计与网络评估体系的设计。网络性能监测系统由控制器主动触发,交换机被动响应。交换机根据控制器下发IP进行网络延迟、网络丢包、时延抖动的测量并上传至控制器,控制器的网络评估模块使用引入相关系数的标准差法对网络性能做出客观准确的判断。最终将网络监测结果提供给多路径网络流优化系统,完成多路径网络路径的最优选择。最后本文通过设计实验和在多路径网络流优化系统中的应用,网络性能监测系统的正确性和可靠性得到的验证。更多还原

【Abstract】 In order to meet the challenges of the network scale getting bigger and more users, network equipment keeps upgrading to satisfy the need. The traditional network framework, that is, controlling and forwarding integration, cannot stand the burden to satisfy the application service. To solve these problems, all over the world dedicated to the study of the future network. In numerous studies, the framework of logic control and data forwarding separation has caused wide public concern. That’s how the concept of Software Defined Network has been defined.The idea of SDN is to separate control layer from forwarding layer, wherein the control logic was installed in the controller, the switch forwards data under the guidance of controller, thus simplified the function of switch. In the meantime, centralized installation which control the logic realized the flexible network configuration. SDN controller has set up flow table for all the paths of forwarding, only on the basis of real network status can ensure the best path. To conclude, the monitor of the network link status is particularly important.This paper relies on laboratory project “study about key technologies based on multi-path flow optimization SDN”, which aims to provide the best path of service selection and maintenance. The content of this paper is to design a objective and accurate network linkage measurement system and provide proper evidence for the controller decision’s best path. The system includes controller design, switch design and network evaluation system.Network performance monitoring system was triggered proactively by controller and the switch passively responds. The switch issues the IP based on the controller to conduct network lag, packet loss and the measurement of jitter & upload to the controller, the usage of network measurement modules of controller involved the correlation index’s standard deviation makes objective and accurate judgement on network performance. Eventually, the results of network measurement were sent to the multi-path network optimization system to finalize the optimal choice.Finally, the accuracy and reliability of the network performance measurement system will be verified by the experiment design and the application of the multi-path network optimization system.更多还原