基于OpenFlow的软件定义网络路由技术研究

发布时间：2018-04-01 01:18

本文选题：软件定义网络　切入点：OpenFlow　出处：《中国科学技术大学》2014年硕士论文

【摘要】：SDN (Software Defined Network)/OpenFlow网络是针对当前网络架构的一场变革,其核心理念是数据转发和控制层面的分离。由于其良好的可控可管理性,SDN/OpenFlow网络已经越来越受到业界的重视。SDN的体系架构可以分为应用层、控制层和设备层。控制器层和设备层分别完成了网络的控制管理和数据包的转发两个功能,应用层则为用户自定义的一些网络应用。OpenFlow网络可以看作为SDN思想的一种具体实现。OpenFlow网络主要由控制器、OpenFlow交换机和OpenFlow标准协议三部分组成,控制器和OpenFlow交换机通过OpenFlow标准协议完成信令的交互。 OpenFlow网络面临的技术挑战：(1)拥塞路由管理问题,传统的网络侧拥塞管理方案是在拥塞节点附近选择数据流进行重路由,这种方案的缺点是不能充分利用网络拓扑资源。以拥塞节点作为锚点进行重路由,在某些情况下,无法选择最优路径,甚至无法得出可行路径。在OpenFlow网络中我们可以利用控制器对网络资源全局管理的优势提出一种更加高效的网络侧拥塞路由管理策略；(2)过渡网络路由问题,OpenFlow网络正处于发展初期,大规模铺设OpenFlow网络并不现实,因此将传统IP网络和OpenFlow网络相结合的过渡网络是一个可行的方案。但是现有的OpenFlow网络的拓扑发现和路由机制本质上使用的都是二层技术,不能很好的融合三层的路由协议,也就不能与传统IP核心网络直接连接通信,限制了网络的可扩展性,因此提出一种过渡网络路由机制是十分有必要的。本文对上述问题进行了深入研究,论文的主要贡献如下： 1) OpenFlow网络中控制器可以对网络进行集中式管理,基于这种特性,本文提出一种与业务属性相关的拥塞路由管理机带CMTA-OF (Congestion Routing Management Based on Traffic Attribution in OpenFlow),以实现更高效的拥塞管理。CMTA-OF机制利用控制器掌握全局网络流量分布的优势,将数据流的业务属性、网络的流量分布和网络的拓扑结构相结合,在拥塞链路处,选择一条或者多条转移开销最小的数据流从网络入口进行重路由。理论分析和实验表明,和传统的拥塞分流策略以及现有的基于OpenFlow网络的LABERIO (LoAd-BalancEd Routing wIth OpenFlow)机制相比,CMTA-OF既能够有效的缓解网络的拥塞状况,保证用户的服务质量,同时还能够提升网络的吞吐量和资源利用率。 2)为了解决过渡网络路由问题,本文提出了一种IP_LLDP (IP Link Layer Discovery Protocol)协议,该协议主要分为IP地址分配、全OFS(OpenFlow Switch)虚拟拓扑构造和地址替换策略三部分。IP_LLDP路由协议能够实现两个OpenFlow交换机通过传统IP网络使用最短路径通信,并且新提出的路由机制的运行不会影响传统IP网络的正常通信,具有良好的可扩展性和独立性。最后我们在实验室搭建了简单的OpenFlow网络实验平台,从拓扑构造,路径计算,流表构造等几个方面对提出的过渡网络路由机制进行了实验验证。
[Abstract]:SDN (Software Defined Network) /OpenFlow network is a revolution in the current network architecture, its core idea is to separate the data forwarding and control level. Because of its good controllability and manageability, SDN/OpenFlow network has been more and more attention in the industry.SDN architecture can be divided into application layer, control layer and device layer. The controller layer and equipment layer respectively completed forwarding two function control management and network data packet, the application layer is the custom of some network applications of.OpenFlow network can be seen as a concrete realization of the idea of SDN network is mainly composed of.OpenFlow controller, OpenFlow switches and OpenFlow standard protocol is composed of three parts, signaling interaction controller and OpenFlow switch through the OpenFlow standard protocol.
The technical challenges faced by OpenFlow networks: (1) the routing congestion management problem, the traditional network congestion management scheme is the choice of data flow rerouting in congestion node near the disadvantages of such a scheme is not sufficient to use the network topology. The congestion node resources as the anchor for rerouting, in some cases, to select the optimal path and even unable to obtain the feasible path. In OpenFlow network, we can manage to use the advantage of global cyber source controller presents a more efficient routing network congestion management strategy; (2) the transition network routing problem, OpenFlow network is in the early stage of development, laying large-scale OpenFlow network is not realistic, so the combination of traditional transition network IP network and OpenFlow network is a feasible scheme. But the existing OpenFlow network topology discovery and routing mechanism in essence making It uses two layers of technology, it can not well integrate the three level routing protocol, and can not directly communicate with the traditional IP core network, which limits the scalability of the network. Therefore, it is necessary to propose a transition network routing mechanism.
This paper makes an in-depth study of the above problems, and the main contributions of this paper are as follows:
1) controller in a OpenFlow network for centralized management of the network, based on this characteristic, this paper proposes a routing congestion management machine and business related attributes with CMTA-OF (Congestion Routing Management Based on Traffic Attribution in OpenFlow.CMTA-OF), in order to achieve congestion management mechanism more efficient controller master flow distribution of global network advantage, business attribute data flow, combining the topology of the network traffic distribution and network congestion, in the link, select one or more transfer with minimum overhead data flow re routing from the network entrance. Theoretical analysis and experimental results show that with traditional congestion diversion strategy and based on the existing OpenFlow network LABERIO (LoAd-BalancEd Routing wIth OpenFlow) mechanism compared to CMTA-OF can effectively alleviate the network congestion, ensure user service Quality, and can also improve the network throughput and resource utilization.
2) in order to solve the transition network routing problem, this paper proposes a IP_LLDP (IP Link Layer Discovery Protocol) protocol, the protocol consists of IP address assignment, OFS (OpenFlow Switch) virtual topology and address replacement strategy three part of the.IP_LLDP routing protocol can achieve two OpenFlow switch using the shortest path through communication the traditional IP network, the operation will not affect the routing mechanism and proposed the normal communication of the traditional IP network, has good scalability and independence. Finally, we set up a simple OpenFlow network experimental platform in the laboratory, from the topological structure, flow path calculation, table structure and several other aspects of the transition network routing mechanism is proposed the experiment was carried out.

【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP393.02

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