Question

Why are Software Defined Networks (SDN) considered an overlay network? Explain in short with example of a well-known overlay networks.

Answer 1

> Software Defined Networks(SDN) is a network which has an approac which allows to control the network centrally using programmed software applications.

> It helps the network operator to control the network consistently, irrespective of what the network technology is used under it.

> Overlay Networking is a method to create layers that can be used to run or control various networks using softwares.

> It creates a layer above the physical network layer. It often helps in providing security to the system.

> Thus, as we see that both the Software Defined Network and an Overlay Network work on the same concept of making multiple layers and controlling the network centrally.

> Hence, they are considered as one. Thus, the Software Defined Networks are often considered as an Overlay Network.

> The biggest example of an overlay network is the internet. There are almost infinite number of overlay networks which run above the physical internet.

> Though, all of the overlay networks are controlled by the central system that is the internet. If the internet goes down worldwide, none of the overlay networks which rely on the internet will run.