Ring-Based Single-Link Failure Recovery Simulation and Analysis

High Availability is one of the main requirements for any network architecture, including SDN. Fast recovery after link failure is an important factor of network availability. In this project, I evaluated the performance of the Ring-based Single-link Failure Recovery approach that was proposed in [1]. The algorithm selects core nodes and forms a ring between them, then selects backup paths for different flows in a way to direct them to go over this ring. The ring is updated periodically according to predicted load. This method improves backup resource utilization and minimizes TCAM resource consumption by reducing the number of flow table entries. On the other side, this approach increases delay and jitter by forcing traffic to go over the shared ring. Some redundant links are never used in this approach. The recalculation process to update the ring may cause instability in the network. The algorithm may introduce routing loops in some cases.