Abstract: SDN helps networks keep up with the speed of change, made possible by virtualization, convergence and cloud, by centralizing and simplifying control thereby making them more agile and programmable. The basic idea is unriddled and whys, whats, hows and whens of software defined networking(SDN) are to be discussed along with its pros and cons. The basic idea behind SDN and the OpenFlow protocol will be explained in detail. Some light would ne shone on the traditional data network along with illuminating the shift to software and why is it needed.

Keywords: OpenFlow, traditional data networks, centralisation of control plane, separation of control, data plane.