Nowadays, the Software-Defined Networking (SDN) is the most important part of research work. SDN offers numerous benefits including on-demand provisioning, automated load balancing, streamlined physical infrastructure and the ability to scale network resources as per the need. SDN has the ability to manage network traffic through software and the administrator gain a much greater degree of control, which provides the ability to change network rules on the fly. In the near future, SDN can replace traditional networking. At the similar time, suspicious awareness necessitates being paid to protection at the early planning phase. In the paper majorly concentrates on the protection attributes of SDN. It starts by examining the architecture of SDN. Along with the design structure, we design the probable protection faults in SDN. Finally discuss various threats and its countermeasures based on three-layer architecture, i.e. data forwarding layer, the control layer, and the application layer. Additionally, those different defensive techniques are highlighted.