Computes all ephemeral runtime state based on configuration from the management plane, disseminates topology information reported by the data plane elements, and pushes stateless configuration to forwarding engines.
The control plane is sometimes described as the signaling for the network. If you are dealing with processing messages in order to maintain the data plane in the presence of static user configuration, you are in the control plane (for example, responding to a vMotion of a virtual machine (VM) is a control plane responsibility, but connecting the VM to the logical network is a management plane responsibility) Often the control plane is acting as a reflector for topological info from the data plane elements to one another for example, MAC/Tunnel mappings for VTEPs. In other cases, the control plane is acting on data received from some data plane elements to (re)configure some data plane elements such as, using VIF locators to compute and establish the correct subset mesh of tunnels.
The set of objects that the control plane deals with include VIFs, logical networks, logical ports, logical routers, IP addresses, and so on.
The control plane is split into two parts in NSX-T, the central control plane (CCP), which runs on the NSX Controller cluster nodes, and the local control plane (LCP), which runs on the transport nodes, adjacent to the data plane it controls. The Central Control Plane computes some ephemeral runtime state based on configuration from the management plane and disseminates information reported by the data plane elements via the local control plane. The Local Control Plane monitors local link status, computes most ephemeral runtime state based on updates from data plane and CCP, and pushes stateless configuration to forwarding engines. The LCP shares fate with the data plane element which hosts it.