【作者】 刘凯；

【导师】 崔鸿雁；

【作者基本信息】 北京邮电大学 ， 电子与通信工程， 2018， 硕士

【摘要】 移动互联网的兴起在给各大互联网企业带来更多用户的同时,也使得企业内部管理的数据中心网络日益庞大,从而导致存在于传统网络中的问题(如配置繁琐、调度不灵活以及设备依赖度高等)变得越来越突出。因此,越来越多的企业开始尝试使用软件定义网络(Software-defined Network,SDN)来部署数据中心,以求解决在传统网络中遇到的问题。随着SDN不断地被应用到实际环境中,与SDN相关的研究和实践也变得越来越具有实际意义。而在SDN环境中,如何为用户提供安全的业务保障服务是实际应用中比较关键的一步。因此,本文通过研究访问控制和业务保障两方面的内容来探讨在SDN环境中如何为用户提供安全的业务保障服务。其中,业务保障部分除了为用户提供基本的QoS(Quality of Service)功能之外,还包括研究如何在链路层面为业务提供链路故障恢复。本文的主要工作如下:1)设计和实现了访问控制系统,为业务保障服务提供了安全保障。本文首先分析了访问控制系统的功能需求,并确定了其功能框架;其次,通过分析系统中的实体关系,为系统设计了权限关系数据库;然后,本文阐述了系统中主要功能模块的实现原理。最后,通过仿真验证了系统能够对业务请求做出预期内的访问控制。2)设计和实现了 QoS功能,为用户提供基本的业务保障。本文首先拟定了 QoS功能的总体框架,接着对网络状态获取、QoS路由计算、路由下发以及REST模块的实现原理进行了阐述。最后,通过仿真验证了 QoS服务能够在带宽和时延上满足用户的业务请求。3)研究了现有的链路故障恢复机制,分析得出现有方案会导致网络中存留大量备用流表,使得其实用性降低。为了降低备用流表在网络中的占比,本文提出了基于重要链路的备用路由改进方案。其中,重要链路的选择依赖于两方面的因素:链路在网络拓扑结构中的关键程度和链路承载的业务流数目。本文通过仿真验证了改进方案中的备用流表占比相比原有方案更低。更多还原

【Abstract】 The rise of mobile Internet had brought more users to major Internet enterprises,meanwhile,it made the data center network managed by the enterprise growing day by day,resulting in the problems existing in the traditional network(such as complicated configuration,inflexible scheduling and high dependence on device)has become more and more prominent.As a result,more and more enterprises are beginning to try to deploy data centers using Software-Defined Network(SDN)in order to solve the problems encountered in traditional networks.As SDN continues to be applied in the real world,research and practice related to SDN have become more and more meaningful.In the SDN environment,how to provide users with safe and guaranteed services is a key step in practical application.Therefore,this paper explores how to provide users with safe and guaranteed services in SDN environment by studying the content of access control and guaranteed services.Among them,the guaranteed services in addition to providing users with the basic QoS(Quality of Service)function,but also try to study how to provide link failure recovery for the business at the link level.The main work of this paper is as follows:1)Designed and implemented an access control system to provide security for guaranteed services.This paper first analyzes the functional requirements of access control system and determines its functional framework.Secondly,it analyzes the entity relations in the system and designs the authority relational database for the system.Then,the paper describes the implementation of the main functional modules in the system.Finally,the simulation verifies that the system can apply the expected access control to the business request.2)Designed and implemented QoS module to provide users with basic guaranteed services.This paper first develops the framework of QoS functions,and then describes the realization of network status acquisition,QoS routing calculation,route delivery and REST module.Finally,the simulation verifies that the QoS service can satisfy the user’s service request in terms of bandwidth and delay.3)Studied the existing link failure recovery mechanism,analysis shows that the existing solution will lead to a large number of backup flow entries in the network,making it less practical.In order to reduce the proportion of backup flow entries in the network,this paper proposes an improved backup routing scheme based on important links.Among them,the choice of important links depends on two factors:the link criticality in the network topology and the number of flows carried by the link.In this paper,we verify the improved scheme compared with the existing scheme by simulation,the results show that the proportion of the backup flow entries in the network is lower.更多还原