Abstract: Software defined networking (SDN) separates the control plane from the data plane, thus the former can be significantly simplified when facing a complex network environment. Since the control plane largely determines the network performance, many companies and institutions have proposed their controllers, some of which are open-source. However, there is a lack of systematic and complete comparison among these controllers. Thus, the researchers have to make their decisions according to their experiences and intuitions due to the insufficient evidences. To address this problem, this paper does a survey of state-of-the-art SDN controllers and compares their architecture and implementation and their performance using Cbench and Mininet. Besides, considering the bottleneck of the single controller in control plane, this paper presents an overview of some distributed controllers. The results have a great reference significance for the researchers to choose the right controllers.

Key words: software defined networking, controller, distributed controllers, performance comparison

摘要： 软件定义网络（software defined networking，SDN）是一种将网络控制平面和数据平面分离的新型网络架构。在SDN网络中，控制器的性能对网络性能有着重要的影响，当前很多公司和科研机构都已经提出了自己的控制器解决方案。然而针对如此众多的控制器，目前没有系统、全面的比较。由于缺乏足够的依据，研究人员只能凭借自己的经验或直觉来选择控制器。为了解决这个问题，对目前主流的SDN控制器在架构和性能上进行了系统的分析比较，并采用Cbench和Mininet对部分开源控制器进行了性能测试，同时针对单一控制器的性能问题，对现有的多控制器控制平面设计进行了分析综述。该研究结果对于研究人员选取正确的控制器具有重要的参考意义。

关键词: 软件定义网络, 控制器, 分布式控制器, 性能比较