The data plane (sometimes known as the user plane, forwarding plane, carrier plane or bearer plane) is the part of a network that carries user traffic. The data plane, the control plane and the management plane are the three basic components of a telecommunications architecture. The control plane and management plane serve the data plane, which bears the traffic that the network exists to carry.
The data plane enables data transfer to and from clients, handling multiple conversations through multiple protocols, and manages conversations with remote peers. Data plane traffic travels through routers, rather than to or from them.
In conventional networking, all three planes are implemented in the firmware of routers and switches. Software-defined networking (SDN) decouples the data and control planes and implements the control plane in software instead, which enables programmatic access to make network administration much more flexible.
Moving the control plane to software allows dynamic access and administration. A network administrator can shape traffic from a centralized control console without having to touch individual switches. The administrator can change any network switch's rules when necessary -- prioritizing, de-prioritizing or even blocking specific types of packets with a very granular level of control.