A comprehensive survey of interface protocols for software defined networks

Software Defined Network implementation has seen tremendous growth and deployment in different types of networks. Compared to traditional networks it decouples the control logic from network layer devices and centralizes it for efficient traffic forwarding and flow management across the domain. This multi-layered architecture has data forwarding devices at the bottom in the data plane, which is programmed by controllers in the control plane. The high-level management plane interacts with the control plane to program the whole network and enforce different policies. The interaction among these planes is done through interfaces that work as communication/programming protocols. In this survey, we present a comprehensive study of these interface and programming protocols, which are primarily classified into southbound, northbound, and east/westbound interfaces. This work first classifies each of them into subcategories and then presents a comprehensive comparative analysis. As the different interfaces have different properties, hence, the sub-classification and their analysis are done using different properties. In addition, we also discuss the impact of different virtualization techniques, such as hypervisors, on interface protocols and inter-plane communication. More over specialized interfaces for emerging technologies such as the Internet of Things and wireless sensor networks are also presented. Finally, the paper highlights several short term and long term research challenges and open issues specific to the SDN interface protocols.