Load Adaptive Controller Fail-Over Mechanism in Distributed SDN Control Platform

Software-Defined Networking(SDN) is an emerging technique that decouples network into centralized control plane and distributed data plane. By achieving a logically centralized control plane with global network view, SDN allows network to be managed by applications that run on the centralized control plane, which enables easier management and faster innovation. However, many of today’s data center network consists of huge number of device which can’t be controlled by a single controller instance. Therefore, a logically centralized, but physically distributed SDN control platform that provides better scalability and reliability is necessary. In order to keep control platform working during controller failure, most existing solutions enable a consensus based leader election that is performed for each switch to ensure at most one controller instance is in charge for each switch, meanwhile local state is backed up among controllers. This thesis presents the insufficient of existing solutions and proposes a load adaptive controller fail-over mechanism for distributed control platform in SDN. Load measurement of controller and its switches are collected to determine the process of switch reconnection when controller failure happens. Concept of state partition is used to ensure state consistency during controller fail-over. A prototype of our mechanism is also implemented, and the result of experiment shows desired results.