According to one aspect of the present invention, a communication unit for realizing a function for ATSSS in a 5GS is provided. A UE transmits a PDU session establishment request message including an MA PDU Request indication and ATSSS Capability, and in a case that an MA PDU session is allowed to be established and that only the user plane resources for one of 3GPP access or non-3GPP access are allowed to be established, the UE receives information indicating that the MA PDU session is allowed to be established, an access type corresponding to the user plane resources allowed to be established, a value indicating a cause of disallowance of establishment of the user plane resource for an access type different from the above-described access type, and a PDU session establishment accept message including ATSSS rules, and establishes the MA PDU session.