Enhanced Controller Fault Tolerant (ECFT) Model for Software Defined Networking

Software Defined Networking (SDN) is a new network design paradigm. SDNs decouple the control plane from the forwarding plane of the network switches. SDN has recently attracted researchers in many ways. SDNs use two modules (1) logically centralized controllers that are responsible for forwarding routing decisions, and (2) switches that are connected to controllers. Controller-failure is one of the significant problems in SDNs. Load of the failed controller has to be distributed among other controllers. Fault tolerance is a desirable characteristic for any network paradigm. In this paper, we design a fault tolerance model called Enhanced Controller Fault Tolerant (ECFT) model. On a controller's failure, the proposed ECFT model focuses on balancing the load among other neighboring controllers. The proposed ECFT uses delay among switches and their associated controllers in order to compute the load for each neighbor controller. Mininet emulator is used to test the proposed model while floodlight is used as the SDN controller. ECFT is compared to Hyperflow which is a distributed control plane for OpenFlow that proposes using multiple controllers to manage Software Defined Networking. ECFT model achieves very promising results in terms of packet delay, packet loss, and average workloads at the controllers when experiencing failures. Results show that the percentage of improvements of using ECFT over Hyperflow is 24%, 20% and 25% in terms of packet delay, packet loss and controller workload respectively.