Hey all, let us try to get acquainted with SDN. Now SDN stands for Software Defined networking. Let me put it like this ‘a software which defines networks’. As we all know, a network is like a map, where all the devices are inter-connected with each other. Devices can be routers, switches, computers, servers or you at one end and me at the other. The network is defined by links between these devices. Using these links data can travel from one point to another. Data can only travel when proper directions are given to the data. Knowing directions, basically means knowing the routes. When all the routes are known, the network is complete and each device can communicate with the other. But the question arises, who will tell the routes? Here is where the software comes in. The job of telling routes to data is known as routing and it is done by a software, which can be named as a controller. So this controller sits at the top level, has an entire view of all the networks beneath it and it guides the data packets. A software has finally defined networking. This is how SDN looks like:
But, isn’t the router/switch doing the same thing? Yes. But SDN is evolved by using the ‘divide and rule’ technique. In router/switch the job of routing and actually forwarding the data is done by themselves, whereas in SDN, both jobs are done by different physical entities. So basically, the routing (control plane) and data forwarding (data plane) are separated. And this is exactly, the wiki definition of SDN.
Let me tell you a short story to make it easier to understand. On Jerry’s birthday, Tom decided to gift cheese to Jerry. Tom knew the address of Jerry but did not know the roads, as he was new in the city. Instead of asking people and then discovering the path, Tom used Google Maps to reach there. Google Maps gave him the best path to Jerry’s place. Jerry was quite happy with his surprise visit and Tom also had a happy journey because of Google Maps. Here, Google Maps becomes the controller, Tom becomes the switch and cheese the actual data. The image here will summarize SDN.
I hope this has introduced SDN to you. Happy networking with SDN…!!!