Method and apparatus for supporting network connection of terminal in next generation mobile communication system

A base station in a wireless communication system, the base station comprising:

• a transceiver;
• and
• a controller configured to:
• transmit system information indicating whether a cell
• is connected to an evolved packet core (EPC) or connected to a 5th generation (5G) core (5GC),
• in case that a terminal is in an idle state:
• in case that the terminal is connecting to the 5GC,
• receive, from the terminal via the transceiver, in case a first identifier of the terminal has been assigned to the terminal from the 5GC, a first message for requesting radio resource control (RRC) connection establishment, wherein the first message includes a first part of the first identifier of the terminal,
• transmit, to the terminal via the transceiver, a second message for the RRC connection establishment as a response to the first message, and
• receive, from the terminal via the transceiver, a third message for confirming the RRC connection establishment as a response to the second message, wherein the third message includes a second part of the first identifier of the terminal, wherein the first identifier consists of the first part of the first identifier and the second part of the first identifier, and
• in case that the terminal is connecting to the EPC,
• receive, from the terminal via the transceiver, in case a third identifier of the terminal has been assigned to the terminal from the EPC, a fourth message for requesting the RRC connection establishment, wherein the fourth message includes the third identifier of the terminal,
• transmit, to the terminal via the transceiver, a fifth message for the RRC connection establishment as a response to the fourth message, and
• receive, from the terminal via the transceiver, a sixth message for confirming the RRC connection establishment as a response to the fifth message, wherein the sixth message for confirming the RRC connection establishment is different from the third message for confirming the RRC connection establishment,
• in case that the terminal is in an inactive state:
• receive, from the terminal via the transceiver, a seventh message for requesting a resumption of a suspended RRC connection, the seventh message including an inactive state radio network temporary identifier (I-RNTI) or a part of the I-RNTI,
• transmit, to the terminal via the transceiver, one of an eighth message for performing an RRC setup procedure or a ninth message to resume the suspended RRC connection, as a response to the seventh message,
• receive, from the terminal via the transceiver, a tenth message for confirming an RRC connection establishment, the tenth message including the first identifier, in case that the eighth message is the one of the eighth message or the ninth message transmitted to the terminal as a response to the seventh message, and
• receive, from the terminal via the transceiver, an eleventh message for confirming an RRC connection resumption, in case that the ninth message is the one of the eighth message or the ninth message transmitted to the terminal as a response to the seventh message.