A Failure-Independent Path-Protecting p-Cycle based Algorithm for a Resilient SDN Control Plane

Abstract

In Software-Defined Networks (SDNs), the separation of the network's control logic via a control plane often composed of multiple physically distributed controllers, from the underlying switches that forward network packets, makes it essential to have a resilient controller-to-switch connection. Additionally, providing resiliency while conforming to stringent latency requirements and utilizing bandwidth efficiently, are key issues especially in Wide Area Networks (WANs). This project proposes FIPP-SDN, a controller placement strategy that uses Kodians's concept of failure-independent path-protecting (FIPP) p-cycles to provide guaranteed single failure protection and fast failover for all controller-to-switch paths, via shared preconnected and bandwidth-efficient backup paths. The strategy is formulated as a Mixed Integer Linear Programming (MILP) model and compared with existing solutions, notably Vizarreta's Resilient Controller Placement-Disjoint Control Paths (RCP-DCP), using 5 network topologies, in terms of average cost. Our evaluation shows that FIPP-SDN has slightly to significantly better performance even with configurations that do not favour it, making it a promising candidate for further study.