Method and device for supporting configuration of time synchronization network in mobile communication network

The disclosure relates to a communication method and system for converging a 5G communication system for supporting higher data rates beyond a 4G system with a technology for IoT. A method of a NW-TT is provided. The method includes receiving a first announce message via user plane from a first DS-TT using a first PDU session between the NW-TT and the first DS-TT, receiving a second announce message from a N6 interface, determining port states for each port of the first DS-TT and the NW-TT with the first and second announce message using a BMCA procedure, if GM is external to a time synchronization network, generating a third announce message based on the first and second announce message for each master port in the first DS-TT and the NW-TT, and transmitting the third announce message to the first PDU session related to the master port in the first DS-TT.