Network - control plane
The control plane in a network is essentially the part of the network that carries administrative traffic. This is the traffic that is responsible for routing and network management, as opposed to user data or payload traffic.
In a router or switch, the control plane is responsible for maintaining tables and information needed to determine the correct path for data to travel through the network. This includes Layer 3 routing protocols like OSPF, EIGRP, BGP, as well as Layer 2 control protocols such as DTP, STP, CDP, VTP, and many more.
Control plane traffic typically (but not always) involves communication between network devices. Thus, the source and destination of control plane traffic are network devices, as opposed to end user devices.
The control plane is in contrast with the data plane, also known as the forwarding plane or the user plane, which is responsible for forwarding traffic to its ultimate destination based on decisions made by the control plane.