A terminal apparatus and an apparatus in a core network exchange information indicating maintenance of a PDU session in a procedure for releasing UP resources, and thereby releases the UP resources associated with a specific PDU session while maintaining establishment of the specific PDU session. A terminal apparatus and an apparatus in a core network further exchange information indicating a release of only the UP resources in a procedure for releasing the UP resources, and thereby the terminal apparatus recognizes the release of the UP resources associated with the specific PDU session. In this manner, in order to release the UP resources associated with the specific PDU session while maintaining establishment of the specific PDU session, and to allow the terminal apparatus to recognize the release of the UP resources, a system and a communication control method are provided.