How Reliable Is My Software-Defined Network? Models and Failure Impacts

Software-Defined Networking (SDN) is a fundamental paradigm shift in communication networks, separating the network control and data planes. This separation enables the dynamic reconfiguration of the data plane at run-time through control plane software. The logically centralized control plane - the network brain - is typically realized in a distributed fashion to avoid a single point of failure, to provide redundancy of key control plane functions vis-a-vis the data plane and to provide horizontal scale-out. As SDN begins to be adopted as the underlying paradigm and platform for carrier-grade networks through the advent of open-source SDN controllers, a deep understanding of the reliability of SDNs is essential to satisfying carrier-grade requirements and fulfilling service-level agreements. To this end, we present a model of SDN reliability under control and data plane failures, that encompasses the distributed nature of the SDN control plane.