Failover mechanism during upgrading process for software-defined networking

The demand for dynamic network management has accelerated the adoption of Software-Defined Networking (SDN). The new networking paradigm has allowed innovations and reduced the complexity in managing large networks. Similar to other software-based element, the SDN controller needs to be upgraded to fix bugs and other security issues even after deployment into the production network. During the upgrading process, the controller may crash causing the network to be disrupted. This paper presents a robust failover mechanism that can synchronize the information between the old and the new controllers using FlowVisor between controllers and switches. The proposed mechanism allows the new controller to continue the upgrading process even when the old controller fails. The effectiveness of the failover mechanism is emulated in two different scenarios namely when the old controller did not crash and when the old controller did crash during the upgrading process. The results show the proposed mechanism incurs zero TCP packet loss for both scenarios during SDN controller upgrading process.