A communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT) is provided. The method includes intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services.The disclosure provides a packet processing method of a transmitter that include transmitting a radio link control (RLC) service data unit (SDU) to a receiver; receiving, from the receiver, a first message including information about whether the RLC SDU is successfully transmitted; and transmitting a first indicator indicating successful transmission of the RLC SDU from an RLC entity of the transmitter to a packet data convergence protocol (PDCP) entity of the transmitter when the receiver receives the RLC SDU.