The present invention relates to a network controller within a core network in a radio communication system, and a method for forming an interface with a terminal. In the network controller, if a terminal requests a predetermined radio node for a connection between the terminal and a core network through a first radio interface by a first radio protocol, a connection to the terminal by a NAS protocol is established and configuration information for the connection to the terminal is stored, and if the terminal requests the radio node for a connection between the terminal and the core network through a second radio interface by a second radio protocol, a connection to the terminal by the NAS protocol may be established using the configuration information.