A first base station for transmitting data in a wireless communication system, comprising: a transceiver ; and at least one processor configured to: transmit (a-1), to an integrated access and backhaul, IAB, donor central unit, CU, of a second base station serving an IAB node, a first configuration request message including information related to transmission of user data transmitted through an IAB donor distributed unit, DU, of the second base station from the first base station to the IAB node, receive (a-2), from the IAB donor CU, a first configuration response message comprising general packet radio service tunnel protocol, GTP, tunnel endpoint information and profile indication information in response to the first configuration request message, wherein the user data comprises a packet transmitted from the first base station to the IAB node through a GTP tunnel indicated by the GTP tunnel endpoint information, wherein at least one of a differentiated service code point, DSCP, field of the packet or a flow label field of the packet is set based on the profile indication information, and wherein the IAB donor CU and the IAB donor DU compose an IAB donor node serving the IAB node. a transceiver ; and at least one processor configured to: transmit (a-1), to an integrated access and backhaul, IAB, donor central unit, CU, of a second base station serving an IAB node, a first configuration request message including information related to transmission of user data transmitted through an IAB donor distributed unit, DU, of the second base station from the first base station to the IAB node, receive (a-2), from the IAB donor CU, a first configuration response message comprising general packet radio service tunnel protocol, GTP, tunnel endpoint information and profile indication information in response to the first configuration request message, wherein the user data comprises a packet transmitted from the first base station to the IAB node through a GTP tunnel indicated by the GTP tunnel endpoint information, wherein at least one of a differentiated service code point, DSCP, field of the packet or a flow label field of the packet is set based on the profile indication information, and wherein the IAB donor CU and the IAB donor DU compose an IAB donor node serving the IAB node. transmit (a-1), to an integrated access and backhaul, IAB, donor central unit, CU, of a second base station serving an IAB node, a first configuration request message including information related to transmission of user data transmitted through an IAB donor distributed unit, DU, of the second base station from the first base station to the IAB node, receive (a-2), from the IAB donor CU, a first configuration response message comprising general packet radio service tunnel protocol, GTP, tunnel endpoint information and profile indication information in response to the first configuration request message, wherein the user data comprises a packet transmitted from the first base station to the IAB node through a GTP tunnel indicated by the GTP tunnel endpoint information, wherein at least one of a differentiated service code point, DSCP, field of the packet or a flow label field of the packet is set based on the profile indication information, and wherein the IAB donor CU and the IAB donor DU compose an IAB donor node serving the IAB node. <EOS>