A survey: Hybrid SDN

In this paper, we present a comprehensive survey of hybrid SDN models, techniques, inter-paradigm coexistence and interaction mechanisms. Firstly, we delineate an overview of hybrid SDN roots and consequently we discuss the definition, architectural pillars, benefits and limitations of hybrid SDN. Further, we categorize the different models under various headings, that can be used for deploying hybrid SDN. Next, we do a comparative analysis of each model. We discuss implementation approaches in each model and challenges that may arise in the deployment of hybrid SDN.