SDN From a Developer's Point of View

I have been following SDN (Software Defined Networking) for quite some time. What I knew about SDN is that it is about virtualization of networking. As a developer, it was always hard for me to visualize the concept of SDN, until not so long ago when I got a chance of attending Cisco Connect (Thanks to my employer).

There I got best ever explanation of what SDN is in under 1 minute by Cory Vokey when I asked him the question what SDN really means for a developer? He explained which I am quoting here in my own words:

Think of SDN as MVC design pattern, where data plane or hardware which makes the flow of data as Model, the software piece which controls the flow of the data as Controller and the interfaces or applications which feed off the Controller as View.

To further clarify SDN concept; following is my best effort to illustrate the concept I formed in my head by keeping the above definition in perspective:

Software Defined Networks (SDN) is an emerging technology which has potential to change the way networking systems are built. SDN is a concept where all the complex logic is pulled out of different dedicated networking appliances and is put into a central system for the sake of scalability and maintainability. The way Hypervisor is used to virtualize compute and memory resources for servers at infrastructure level similarly SDN is used to virtualize the networking capacity of a network at infrastructure level.