This work proposes an adaptable failover mechanism for use in the control plane that combines various controllers to deal with controller failure to ensure that controller failure is tolerable. Each controller in the cluster of controllers has one of two roles: leader and member. The failover system is composed of four components, which are state monitor, failure detector, event actor and schedule handler. The failover mechanism reduces the overall network failover time, improves network stability and optimizes the processing performance in the data plane. This work analyzes thefailover mechanism that is based on a controller cluster in software-defined networking. The results thus obtained revealthat the proposed mechanism effectively detects a failed controller, and the failover mechanism reduces the failover time by 22.46%.

1. S. A. Shah, J. Faiz, M. Farooq, A. Shafi and S. A. Mehdi, “An architectural evaluation of SDN controllers,” in IEEE International Conference on Communications (ICC), 2013, pp. 3504-3508. https://dx.doi.org/10.1109/icc.2013.6655093
   
2. S. Betge-Brezetz, G. B. Kamga and M. Tazi, “Trust support for SDN controllers and virtualized network applications,” in 1st IEEE Conference on Network Softwarization (NetSoft), 2015, pp. 1-5. https://dx.doi.org/10.1109/netsoft.2015.7116153
   
3. S. Baik, C. Hwang and Y. Lee, “SDN-based architecture for end-to-end path provisioning in the mixed circuit and packet network environment,” in Network Operations and Management Symposium (APNOMS), 16th Asia-Pacific, 2014, pp. 1-4. https://dx.doi.org/10.1109/apnoms.2014.6996572
   
4. M. A. Santos, B. A. Nunes, K. Obraczka, T. Turletti, B. T. de Oliveira and C. B. Margi, “Decentralizing SDN’s control plane,” in 39th Annual IEEE Conference on Local Computer Networks, 2014, pp. 402-405. https://dx.doi.org/10.1109/LCN.2014.6925802
   
5. A. Dixit, F. Hao, S. Mukherjee, T. V. Lakshman and R. Kompella, “Towards an elastic distributed SDN controller,” in ACM SIGCOMM Computer Communication Review, vol. 43, no. 4, pp. 7-12, 2013. https://dx.doi.org/10.1145/2534169.2491193
   
6. M. Karl, J. Gruen and T. Herfet, “Multimedia optimized routing in openflow networks,” in 19th IEEE International Conference on Networks (ICON), 2013, pp. 1-6. https://dx.doi.org/10.1109/ICON.2013.6781969   PMid:24064001  
7. S. Y. Wang, “Comparison of SDN open flow network simulator and emulators: EstiNet vs. Mininet,” in IEEE Symposium on Computers and Communications (ISCC), 2014, pp. 1-6.
   
8. A. Bianco, V. Krishnamoorthi, L. Nanfang and L. Giraudo, “OpenFlow driven ethernet traffic analysis,” in International Conference on Communications (ICC), Sydney, Australia, 2014, pp. 3001-3006. https://dx.doi.org/10.1109/icc.2014.6883781

Y. Ma, Y. Tsai, J. Chen, D. Jiang and J.Jhou “An adaptable failover mechanism in controller cluster for software-defined networking,” International Journal of Technology and Engineering Studies, vol. 2, no. 6, pp. 185-188, 2016.