Provided is a communication procedure for data transmission and/or reception suitable for a Network Slice and a DeCOR. One or a plurality of Network Slices are included in a core network managed by the network operator, the Network Slice is configured of one or a plurality of Network Functions, and based on registration information of a terminal apparatus or a request of the terminal apparatus, the terminal apparatus performs processing to connect to the one or the plurality of Network Slices corresponding to a service or an application. Furthermore, based on an authentication result from the network, the terminal apparatus performs processing to connect to a supplemental Network Slice.