As another embodiment, in operation 9-15, when the SN transfers a current source configuration of the SN to the MN through a container or octet strings, the MN may transfer the configuration to a T-SN so that the configuration is included as a container of an SN RRC reconfiguration message made by the T-SN. When the SN RRC reconfiguration message made by the T-SN is transferred back to the MN, the MN may encapsulate the SN RRC reconfiguration message in an RRC reconfiguration message of the MN, and transparently transfer the message to the terminal. Each of the message of operation 9-15 and the message of operation 9-20 is required to include a source cell configuration and condition made by the S-SN, and the message of operation 9-30 or the message of operation 9-45 is required to include a container of source cell configuration information made by the S-SN and sCHO configuration information as a T-SN part in an RRC reconfiguration message made by the T-SN. This case may correspond to a case of a signal structure diagram of FIG. JI B. That is, as an MN RAT-based message transferring sCHO configuration information to the terminal, an RRC reconfiguration message made by MN RAT-based RRC includes an SN RAT-based RRC reconfiguration message made by a T-SN as illustrated in