The present disclosure relates to a communication technique for converging IoT technology with a 5G communication system for supporting a higher data transfer rate beyond a 4G system, and a system therefor. The present disclosure can be applied to intelligent services (e.g., smart homes, smart buildings, smart cities, smart or connected cars, health care, digital education, retail business, and services associated with security and safety) on the basis of 5G communication technology and IoT-related technology. Disclosed are a method and an apparatus for configuring an efficient hierarchical layer 2 architecture and main functions thereof in a next-generation mobile communication system.