软件定义空间信息网络半物理仿真平台的构建与应用研究

发布时间：2018-08-14 17:01

【摘要】：空间信息网络通过信息载体(空间平台)来实时获取、传输和处理空间信息,其中空间平台是一种大范畴,包含有卫星、飞艇以及航空器等等。然而传统的卫星网络存在配置慢,业务调度低效以及不灵活的服务交付等问题,这些都对当前的空间信息网络的发展形成桎梏,而这些问题产生的根源在于传统卫星通信系统的设计。新兴的网络技术SDN(Software Defined Network,软件定义网络)的发展,给国内外的研究学者提供了解决的新方法:软件定义空间信息网络。本文对软件定义空间信息网络及其关键技术进行了研究,具体包括以下几个方面:首先,由于目前国内外对于软件定义空间信息网络的研究都只是进行了总体框架的研究,对实现软件定义空间信息网络的关键技术研究较为匮乏。为了进行软件定义空间信息网络的相关技术研究的测试实验,本文根据现有的软件定义空间信息网络架构研究,以及卫星网络的特点(拓扑动态性、链路特性等),以SDN和虚拟化技术为主要技术支撑,搭建了面向SDN的软件定义空间信息网络的半物理仿真平台,部署了 OpenFlow网络设备,在功能上实现了卫星网络拓扑创建、链路参数动态配置、轨迹模拟等模块,初步构建了软件定义空间信息网络实验平台,可以为开展软件定义空间信息网络研究提供了分析工具、测试手段。其次,由于馈线链路会受到影响而导致中断,所以需要在控制器上部署一个网关切换应用来解决链路中断而导致的业务重路由难题。本文在RYU控制器上开发了网关切换应用,将网关切换应用分为两个模块来实现:链路中断检测和网关切换机制。其中链路中断检测是在链路拓扑发现协议模块的基础上开发的,在实时检测拓扑的同时,对必要的信息进行存储和处理。网关切换机制是在恢复机制的基础上开发的,当有馈线链路中断事件发生时,OpenFlow设备通知控制器,控制器则删除受故障影响的流表,并且重新计算工作路径,更新或者下发新的流表规则。通过两个模块的组合来实现快速检测到链路中断,并且迅速切换业务到合适的卫星网关,来解决连路中断导致的业务中断问题,保障网络服务。最后,使用本文搭建的软件定义空间信息网络半物理仿真平台对开发的网关切换应用进行测试,并在相同的空间通信环境下,出现馈线链路中断时,获取重路由到可用的卫星网关上所需要的时间。测试结果证明了基于RYU开发的网关切换应用的有效性。并且,在相同的空间信息网络场景下,软件定义空间信息网络对比传统空间信息网络,基于RYU上开发的网关切换应用对比传统路由,在链路中断时,业务恢复速率优势明显,网络可靠性更高。
[Abstract]:Spatial information network can acquire, transmit and process space information in real time through information carrier (space platform). Space platform is a kind of large category, including satellite, airship, aircraft and so on. However, the traditional satellite network has some problems, such as slow configuration, inefficient service scheduling and inflexible service delivery, which all form shackles to the development of the current spatial information network. The root of these problems lies in the design of traditional satellite communication system. The development of new network technology (SDN (Software Defined Network, software defines network) provides a new method to solve the problem: software defined spatial information network (SDN) at home and abroad. This paper studies the software definition spatial information network and its key technologies, including the following aspects: firstly, because the research of software definition spatial information network at home and abroad has only carried on the overall framework research. The research on the key technology of software defining spatial information network is scarce. In order to test and test the related technologies of software defined spatial information network, this paper studies the architecture of the existing software defined spatial information network and the characteristics of satellite network. Based on SDN and virtualization technology, a semi-physical simulation platform for SDN oriented software defining spatial information network is built, OpenFlow network equipment is deployed, and satellite network topology is created functionally. The dynamic configuration of link parameters, trajectory simulation and other modules, a preliminary software definition spatial information network experimental platform is constructed, which can provide an analysis tool and test means for the research of software defined spatial information network. Secondly, because the feeder link will be affected, it is necessary to deploy a gateway switch on the controller to solve the traffic rerouting problem caused by the link interruption. In this paper, the gateway switch application is developed on the RYU controller. The gateway switch application is divided into two modules: link interrupt detection and gateway handover mechanism. Link interrupt detection is developed on the basis of link topology discovery protocol module. The necessary information is stored and processed while the topology is detected in real time. The gateway handover mechanism is developed on the basis of the recovery mechanism. The OpenFlow device notifies the controller when a feeder link interrupt event occurs, and the controller deletes the flow table affected by the fault and recalculates the work path. Update or issue new stream table rules. Through the combination of the two modules, the link interrupt can be detected quickly, and the service can be switched to the appropriate satellite gateway quickly to solve the problem of the service interruption caused by the connection interrupt and to ensure the network service. Finally, the semi-physical simulation platform of spatial information network is used to test the gateway switching application, and the feeder link is interrupted in the same space communication environment. Gets the time required to reroute to the available satellite gateway. The test results show the effectiveness of gateway switching application based on RYU. Moreover, under the same spatial information network scenario, the software defined spatial information network pair is better than the traditional spatial information network, and the gateway switching application based on RYU is better than the traditional route. When the link is interrupted, the advantage of service recovery rate is obvious. The network is more reliable.
【学位授予单位】：武汉大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN927;TP391.9

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