Failure Recovery In SDN: A Segment Routing Based Link Protection Approach

The present computer network has been evolved into a complex structure with a growing challenge to manage and scale modern day’s requirements. A new approach to tackle these difficulties is SDN, which empowers network with programmability and is designed to perform fine grained traffic forwarding decisions. However, similar to the need of traditional networks, fault tolerance is necessary to achieve high availability. In this thesis, we propose a link protection method based on the Segment Routing (SR) for rapid failure recovery in OpenFlow based SDN. Our proposed scheme performs local recovery at the switch level without the controller intervention, thus significantly reducing the total recovery time. Additionally, it reduces initial load on the controller while proactively computing the backup paths by minimizing the algorithm complexity. Moreover, memory efficiency is achieved by using a per-link protection with aggregated flow rules instead of traditional per-flow based protection mechanism. In Segment Routing, we may encounter the limitation on the size of the label stack, known as Segment List Depth (SLD). Therefore, we also propose an efficient label encoding algorithm to mitigate the SLD impact.