What is SDN (security-defined networking)

Software-defined networking (SDN) is an approach to computer networking that allows network administrators to manage network services through abstraction of lower-level functionality.

Originally, SDN focused solely on separation of the control plane of the network, which makes decisions about how packets should flow through the network from the data plane of the network, which actually moves packets from place to place.
Here is standard SDN framework:

We are using SDN, because of:

• Direct Programming;

• Centralized Management;

• Reduce CapEx;

• Reduce OpEX;

• Deliver Agility and Flexibility.

SDN delivers speed and agility when deploying new applications and business services.