BGP路由策略冲突引发的路由振荡研究

发布时间：2019-04-20 08:41

【摘要】：Internet是一个巨大的资源网和通信网,它是由千千万万个称为自治系统(简称AS)的路由域构成。其中每个自治系统分别从属于不同的网络服务提供商。系统内部路由器之间通过内部网关协议来交换路由信息,自治系统之间路由器之间则是通过外部网关协议来交换路由信息和进行路由选择,边界网关协议BGP是目前运行于Internet上的事实上的外部网关协议。BGP协议是根据自治系统所制定的路由策略来选择抵达目的网络的最佳路由,由于各方面利益的原因,每个自治系统都独立制定自身的路由策略,这样所制定出的路由策略往往存在冲突。研究表明路由策略冲突会导致BGP路由振荡的发生。所谓BGP路由振荡就是指多个自治系统之间不断交换BGP路由信息,使得BGP路由不能收敛于稳定的路由。BGP路由不稳定会影响整个网络的性能。本文首先分析了实例中路由选择过程,阐明了路由振荡现象,根据路由振荡现象,详细的分析产生振荡的原因。其次,对BGP路由的震荡的抑制过程出现的相关的问题进行了研究,并提出了方案的分析和方法,来解决研究在实际网络中使用它的范围,找出当前解决BGP快速的收敛中遇到的问题,便于下一步优化。在对边界网关路由振荡进行分析之后,提出了对于解决BGP路由振荡的方案,进而解决BGP路由策略冲突所造成的路由振荡问题。通过Griffin T G提出简单路径向量协议,对在路由策略发生冲突的情况下所产生的最佳路由作上标记,表明该路由与策略的冲突有关,在后续的路由选择中如果该路由要是再次被标记,就表明路由策略冲突导致的路由振荡发生。当路由策略导致路由振荡发生时,不再选择被标记的路由,而是选择具有较短AS路径的路由,这样就可以消除路由振荡。为了检测路由策略冲突,消除路由振荡,对BGP协议进行了修改使之携带与策略冲突检测相关的信息。运用网络仿真工具SSFNET对改进后的路由协议进行测试,证实了所给方法的有效性。
[Abstract]:Internet is a huge resource network and communication network. It is composed of thousands of routing domains called Autonomous system (AS). Each autonomous system is subordinate to a different network service provider. Internal routers exchange routing information through internal gateway protocols, while routers between autonomous systems exchange routing information and routing through external gateway protocols. The Border Gateway Protocol (BGP) is the de facto external gateway protocol running on the Internet. The protocol is the best route to reach the destination network according to the routing policy established by the autonomous system, due to various interests. Each autonomous system makes its own routing policies independently, so the routing policies are often conflicting. Research shows that routing policy conflicts will lead to the occurrence of BGP routing oscillation. The so-called BGP routing oscillation refers to the continuous exchange of BGP routing information among multiple autonomous systems, which makes the BGP routing unable to converge to stable routes, and the instability of BGP routing will affect the performance of the whole network. In this paper, the route selection process in an example is analyzed, and the phenomenon of route oscillation is clarified. According to the phenomenon of route oscillation, the causes of the oscillation are analyzed in detail. Secondly, the related problems in the process of suppressing the oscillation of BGP routing are studied, and the analysis and method of the scheme are put forward to solve the problem of using it in the actual network. Find out how to solve the problems encountered in the fast convergence of BGP, which is convenient for the next optimization. After analyzing the routing oscillation of the border gateway, this paper proposes a scheme to solve the BGP routing oscillation, and then solves the routing oscillation problem caused by the conflict of the BGP routing policy. A simple path vector protocol is proposed by Griffin T G, which marks the best route in the case of conflict of the routing policy, which indicates that the route is related to the conflict of the policy. If the route is marked again in the subsequent route selection, the route oscillation caused by the routing policy conflict will occur. When the routing policy results in route oscillation, the marked route is no longer selected, but the route with shorter AS path is chosen, so that the route oscillation can be eliminated. In order to detect routing policy conflicts and eliminate routing oscillations, the BGP protocol is modified to carry information related to policy conflict detection. The improved routing protocol is tested by the network simulation tool SSFNET, and the effectiveness of the proposed method is verified.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP393.05

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