As SDN migrates to wide area networks and 5G core networks, a scalable, highly reliable, low latency distributed control plane becomes a key factor that differentiates operator solutions for network control and management. In order to meet the high reliability and low latency requirements under time-varying volume of control traffic, the distributed control plane, consisting of multiple controllers and a combination of out-of-band and in-band control channels, needs to be managed dynamically. To this effect, we propose a novel programmable distributed control plane architecture with a dynamically managed in-band control network, where in-band mode switches communicate with their controllers over a virtual overlay to the data plane with dynamic topology. We dynamically manage the number of controllers, switches, and control flows assigned to each controller as well as traffic over control channels achieving both controller and control traffic load-balancing. We introduce “control flow table” (rules embedded in the flow table of a switch to manage in-band control flows) in order to implement the proposed distributed dynamic control plane. We propose methods for off-loading congested controllers and congested in-band control channels using control flow tables. A validation test-bed and experimental results over multiple topologies are presented to demonstrate the scalability and performance improvements achieved by the proposed dynamic control plane management procedures when the controller CPU and/or availability or throughput of in-band control channels becomes bottlenecks.

In this study, we aim to analyze how Software Defined Networking (SDN) can help to ensure a high-quality uninterrupted Voice over Internet Protocol (VoIP) service accompanied by video for prioritized users and entities in a network congested with background traffic. Guaranteeing a level of Quality of Service (QoS) and resource prioritization are key concepts for future networks (e.g., 5G, NGSON) and may be required in an emergency situation such as an international disaster recovery operation. Providing QoS in such scenarios with the help of SDN is promisingly feasible, via limiting bandwidth, assigning flows to different queues and/or adapting routing decisions based on network conditions. The experiments conducted throughout the study are the substances of the EC FP7 project OFERTIE and Celtic-Plus project SIGMONA. Here we compared loss rate, latency and the jitter as QoS metrics under several scenarios and results showed that we can flexibly manage the QoS by reducing more than 5% loss rate and more than 50% of latency and jitter.