A terminal apparatus or a device in a core network exchanges capability information for each function in a registration procedure or a PDU session establishment procedure, and in user data communication additional information is added into an uplink packet to implement terminal apparatus-initiated RQoS control, and additional information is added into a downlink packet to implement network device-initiated RQoS control. A dedicated control message and information for an authentication and/or authorization function by a DN are defined to implement the authentication and/or authorization function by the DN. Furthermore, the terminal apparatus and the device in the core network have a timer or a control process for each network slice to implement a management process such as congestion management for each network slice. This provides a communication control method in order to implement the terminal apparatus-initiated or network-initiated RQoS control, implement the authentication and/or authorization function by the DN, and implement the management process such as congestion management for each network slice.