The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method performed by a first node in a wireless communication system, including receiving, from a second node, downlink user data through a first radio bearer, the downlink user data including multicast service data; transmitting, to at least one UE, the downlink user data through a second radio bearer; and transmitting, to the second node, a downlink data delivery status including PDCP sequence number information, wherein the PDCP sequence number information includes a higher PDCP sequence number between a highest PDCP sequence number successfully delivered in sequence associated with a first transmission mode and a highest PDCP sequence number transmitted to lower layers associated with a second transmission mode.