软件定义网络链路失效管理机制研究
发布时间：2019-06-14 13:14
【摘要】：随着互联网的高速发展,网络已经深入到人们的各个方面,每条链路上承载流量也越来越重要,链路失效问题日渐突出。软件定义网络(Software Defined Network,SDN)是一种新型网络架构,将数据平面和控制平面相分离,可以更灵活地部署网络应用来解决链路失效问题。本文主要研究软件定义网络中链路失效问题。根据网络中链路失效的规模,该问题可以分为单链路失效和多链路失效两种情形,本文针对这两种情形分别提出相应链路恢复算法。在单链路失效问题中,本文提出基于流聚合的本地快速重路由和基于拥塞避免的快速重路由两种算法。基于流聚合的本地快速重路由算法利用软件定义网络中流表匹配的灵活性,如果一条链路发生失效,所有被中断的业务会被聚合成一条“大”的业务,然后SDN控制器动态地部署一条本地恢复路径代替失效链路。通过仿真结果可以得出,该算法可以减少SDN控制器更新流表项的数量,同时快速恢复被中断业务。而基于拥塞避免的快速重路由是在前者的基础上,考虑链路容量以及业务带宽,将被中断业务聚合为多个“中等”业务并部署在不同的本地恢复路径上,从而有效避免业务恢复后造成链路拥塞的问题。但是该算法的失效恢复时延略微有所增加,所以在单链路失效发生时,需要根据网络负载情况选择相应的算法进行恢复。在多链路失效问题中,考虑到网络拓扑改变较大而且网络中大部分业务可能受到影响,逐一恢复每个被中断业务的效率较低。本文提出基于生成树的快速恢复算法,在链路失效后,以树的形式连接所有有效交换机,在SDN控制器统一更新交换机流表后,所有受影响的业务会自动被恢复。利用树结构的特殊性,在失效恢复过程中,可以减少控制器对流表操作,从而实现快速失效恢复。
[Abstract]:With the rapid development of the Internet, the network has penetrated into all aspects of people, and the traffic on each link is becoming more and more important, and the problem of link failure is becoming more and more prominent. Software defined Network (Software Defined Network,SDN) is a new network architecture, which separates the data plane from the control plane and can deploy network applications more flexibly to solve the link failure problem. In this paper, the problem of link failure in software-defined networks is studied. According to the scale of link failure in the network, the problem can be divided into single link failure and multi-link failure. In this paper, the corresponding link recovery algorithms are proposed for these two cases. In the problem of single link failure, this paper proposes two algorithms: local fast rerouting based on flow aggregation and fast rerouting based on congestion avoidance. The local fast rerouting algorithm based on flow aggregation makes use of the flexibility of software to define the matching of flow table in the network. If a link fails, all interrupted traffic will be aggregated into a "large" service, and then the SDN controller will dynamically deploy a local recovery path instead of the failed link. Through the simulation results, it can be concluded that the algorithm can reduce the number of update stream table items of SDN controller and restore the interrupted traffic quickly. The fast rerouting based on congestion avoidance is based on the former, considering link capacity and service bandwidth, the interrupted traffic is aggregated into multiple "medium" services and deployed on different local recovery paths, so as to effectively avoid the problem of link congestion caused by traffic recovery. However, the failure recovery delay of the algorithm increases slightly, so when the single link failure occurs, the corresponding algorithm needs to be selected according to the network load. In the problem of multi-link failure, considering that the network topology changes greatly and most of the traffic in the network may be affected, it is inefficient to restore each interrupted traffic one by one. In this paper, a fast recovery algorithm based on spanning tree is proposed. After link failure, all effective switches are connected in the form of tree. After the SDN controller updates the switch flow table uniformly, all affected services will be automatically restored. Taking advantage of the particularity of tree structure, the controller convective meter operation can be reduced in the process of failure recovery, so that the rapid failure recovery can be realized.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP393.02
本文编号：2499413
[Abstract]:With the rapid development of the Internet, the network has penetrated into all aspects of people, and the traffic on each link is becoming more and more important, and the problem of link failure is becoming more and more prominent. Software defined Network (Software Defined Network,SDN) is a new network architecture, which separates the data plane from the control plane and can deploy network applications more flexibly to solve the link failure problem. In this paper, the problem of link failure in software-defined networks is studied. According to the scale of link failure in the network, the problem can be divided into single link failure and multi-link failure. In this paper, the corresponding link recovery algorithms are proposed for these two cases. In the problem of single link failure, this paper proposes two algorithms: local fast rerouting based on flow aggregation and fast rerouting based on congestion avoidance. The local fast rerouting algorithm based on flow aggregation makes use of the flexibility of software to define the matching of flow table in the network. If a link fails, all interrupted traffic will be aggregated into a "large" service, and then the SDN controller will dynamically deploy a local recovery path instead of the failed link. Through the simulation results, it can be concluded that the algorithm can reduce the number of update stream table items of SDN controller and restore the interrupted traffic quickly. The fast rerouting based on congestion avoidance is based on the former, considering link capacity and service bandwidth, the interrupted traffic is aggregated into multiple "medium" services and deployed on different local recovery paths, so as to effectively avoid the problem of link congestion caused by traffic recovery. However, the failure recovery delay of the algorithm increases slightly, so when the single link failure occurs, the corresponding algorithm needs to be selected according to the network load. In the problem of multi-link failure, considering that the network topology changes greatly and most of the traffic in the network may be affected, it is inefficient to restore each interrupted traffic one by one. In this paper, a fast recovery algorithm based on spanning tree is proposed. After link failure, all effective switches are connected in the form of tree. After the SDN controller updates the switch flow table uniformly, all affected services will be automatically restored. Taking advantage of the particularity of tree structure, the controller convective meter operation can be reduced in the process of failure recovery, so that the rapid failure recovery can be realized.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP393.02
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