A terminal apparatus for communicating with a base station apparatus, the terminal apparatus including: a receiver configured to receive, from the base station apparatus, a Radio Resource Control (RRC) reconfiguration message including a radio bearer configuration information element; and a processing unit configured to, in a case that a radio bearer identity included in the radio bearer configuration information element is not part of a configuration of the terminal apparatus and that the radio bearer configuration information element includes a Service Data Adaptation Protocol (SDAP) configuration information element and that a Protocol Data Unit (PDU) session information element included in the SDAP configuration information element is not part of the configuration of the terminal apparatus, indicate to upper layers that a user-plane resource is configured for a PDU session corresponding to a value of the PDU session information element.