%A GUAN Jianfeng,NIU Xiaotong,GAO Xianming,YAN Zhiwei %T A Survey on Multi-controller Consensus Mechanisms %0 Journal Article %D 2021 %J Frontiers of Data and Computing %R 10.11871/jfdc.issn.2096-742X.2021.01.002 %P 15-33 %V 3 %N 1 %U {http://www.jfdc.cnic.cn/CN/abstract/article_106.shtml} %8 2021-02-20 %X

[Background] With the increasing application of blockchain in infrastructures of the new generation of Internet in terms of the domain name, routing and public key system, the importance of blockchain is becoming increasingly prominent. As the core technology of blockchain or even the whole field of distributed system, consensus algorithms directly affect the transaction processing capacity, scalability and security of blockchain, as well as their role as a foundation in Internet infrastructure. [Objective] In this paper, we introduce the consensus mechanism for sharing data among multiple controllers in Software Defined Network (SDN), analyze the problems existing in the current design and propose solutions, and provide a reference for relevant research work. [Methods] Based on the classic distributed consensus algorithms, this paper summarizes the research status of consensus mechanism with a focus on the consensus in the multi-controller layer of SDN and the existing problems, proposes solutions based on the blockchain technology, and introduces the current research status of applying blockchain technology to SDN. [Results] The consensus mechanisms in the multi-controller cluster of SDN are mainly represented by Raft-like fault-tolerant consensus mechanisms in actual deployment, which cannot deal with the malicious behaviors to controllers or switches. Some existing researches have tried to introduce Byzantine fault-tolerant consensus mechanism, and improve the system performance adaptively. However, in the current SDN control layer, the consensus mechanism used to realize data sharing among controllers still has some problems, such as inflexible deployment of consensus network and huge cost caused by the controller consensus mechanism. [Conclusions] The third-party data-sharing service on controller layer based on blockchain proposed in this paper has advantages in security, credibility and flexible deployment, etc., which can provide solutions to solve the above mentioned problems. As an extended architecture of data sharing service, the credible blockchain-based SDN infrastructure proposed in this paper can provide a variety of secure and trusted services for SDN.