NSX Controller is an advanced distributed state management system that controls virtual networks and overlay transport tunnels.
NSX Controller is deployed as a cluster of highly available virtual appliances that are responsible for the programmatic deployment of virtual networks across the entire NSX-T architecture. The NSX-T Central Control Plane (CCP) is logically separated from all data plane traffic, meaning any failure in the control plane does not affect existing data plane operations. Traffic doesn’t pass through the controller; instead the controller is responsible for providing configuration to other NSX Controller components such as the logical switches, logical routers, and edge configuration. Stability and reliability of data transport are central concerns in networking. To further enhance high availability and scalability, the NSX Controller is deployed in a cluster of three instances.