What is SDN?

What is SDN?

Software Defined Networking defines the Network functions using software.

It is not a technology, it's just a concept to centralize Network configuration.

we can categorize Networking into two ways:

Legacy Networking 

SDN Networking

Legacy Networking:

In traditional Networking every device whether it is a switch, router or firewall has

its own control part, which is decentralized from each other. In this scenario, each Network device, process network packet and decide destination for it,

This results in the manual configuration of each of the network device so that each device can 

process packets according to the network configurations. There is always the high possibility of

errors and misconfigurations over devices. 

One more point of concern is that in a Network there can be numerous Network devices developed

by different vendors like CISCO, Juniper, NEC, Broadcom. All these vendors have the different set of API's 

to control the data path of these Network devices. Which results in more chances of misconfiguration 

over Network devices and Network management becomes a tedious task for Administrators.

SDN Networking:

SDN is a new concept that divides the data plane and control plane. It manages the data plane via

a centralize interface which connects all the data plane to the control plane.

In SDN, only one control plane is equipped to manage all the data planes of the Network. means one 

control plane (controller) can manage all the data planes of different vendors. 

This concept simplifies the configuration over Network devices and minimizes the chances 

of misconfiguration.