Now that we have defined what network virtualization is about, let's go over some of the key concepts of network virtualization and software-defined networking:

• Decoupling: An important concept of network virtualization is the decoupling of software and the networking hardware. The software works independently of the networking hardware that physically interconnects the infrastructure. Any networking hardware that can inter-op with the software is always going to enhance the functionality, but it is not necessary. Remember that your throughput on the wire will be always limited by your network hardware performance.
• Control plane: The decoupling of software and networking hardware allows you to control your network better because all the logic resides in the software. This control aspect of your network is called the control plane. The control plane provides the means to configure, monitor, troubleshoot, and also allow automation against the network.
• Data plane: The networking hardware forms the data plane where all the data is forwarded from source to destination. The management of data resides in the control plane; however, the data plane consists of all the networking hardware whose primary function is to forward traffic over the wire from source to destination. The data plane holds all the forwarding tables that are constantly updated by the control plane. This also prevents any traffic interruptions if there is a loss of the control plane, because the networking hardware, which constitutes the data plane, will continue to function without interruptions.
•  Application Programming Interface (API): The API is one of the important aspects of a virtualized network and allows for true software-defined networking by instantly changing the network behavior. With the API, you can now instantly deploy rich network services in your existing network. Network services such as Edge gateway, VPN, Firewall, and load balancers can all be deployed on the fly by means of an API.