On Designing a Resilient SDN C/M-Plane for Multi-Controller Failure in Disaster Situations

Network survivability is the ability to maintain service continuity in the presence of failures. This ability might be critical in times where large-scale failures occur, as in the case of disasters. In the past years, Software Defined Networking (SDN) has shown a great potential to allow network programmability by segregating the Control/Management Plane (C/M-Plane) from the forwarding or Data Plane (D-Plane). The controller, a centralized entity, has an overview of the entire network under its domain, which allows it to make informed routing decisions. However, the controller becomes a single-point-of-failure as network devices will have limited knowledge if not connected to a controller. Moreover, in disaster situations, if the affected area is considerably large, there is a high probability that more than a single controller will fail in a short period. Various studies, either following a protection or restoration techniques, have been proposed to address resiliency on SDN, but most of them only consider link or device failure; however, the failure of various controllers due to a large-scale disaster is less explored. In this paper, we consider multi-controller failure and propose a mechanism to reduce the non-operational network devices in disaster situations. Preliminary results show that, by applying the proposed approach, it is possible to achieve substantial improvements in network survivability, with considerably less cost of implementation than existing methods. In particular, using simulation, we achieved a 20% decrease of non-operational devices at the C/M-Plane; and an increase of 30% of success rate at the D-Plane, even if half of the controllers in the topology failed.