Software Defined Networking

A technology that allows network and security professionals to manage, control, and make changes to a network.

SDN is basically a giant UI wrapper for the many different text-based configuration files scattered across the many services and machines that compose a network. 

SDN Layers (Raw Lesson Content)

There are three of them.

Layer	Description
Application	The Application layer communicates with the Control layer through what is called the northbound interface. These are sometimes called northbound APIs.
Control	The Control layer receives its requests from the Application layer and then provides the Physical layer with its configuration and instructions.
Physical	The Physical layer, also known as the Infrastructure layer, communicates to the Control layer through the southbound interface. The individual networking devices use southbound APIs to communicate with the control plane and vice versa. Even though this layer is called the Physical layer, it is where both physical and virtual network devices sit.

Tradeoffs of SDN

You get:

• centralized management
• more granular, fine-tuned control
• lower costs and labor
• revive older hardware
• easily gather network statistics
• vendor crossplay

I get:

• very new technology
• lack of vendor support
• no definitive standard for the SDN technology
• centralized control = a new target for security breaches