Section: 4.15.9 Time Synchronization exposure 4.15.9.1 General
Content: Time synchronization exposure allows an AF to configure time synchronization in 5GS. For (g)PTP operation, the Time synchronization service allows an AF to subscribe to the UE and 5GC capabilities and availability for time synchronization service (as described in clause 4.15.9.2), to configure the (g)PTP instance in 5GS as described in clause 4.15.9.3 and monitor service status as described in clause 4.15.9.5. For 5G access stratum based time distribution, the AF can influence the 5G access stratum time distribution as described in clause 4.15.9.4 and monitor service status as described in clause 4.15.9.5. The time synchronization exposure is provided by NEF that uses the service provided by TSCTSF. The AF that is part of operator's trust domain may invoke the services directly with TSCTSF and TSCTSF responds/notifies directly to the AF, accordingly. NOTE: The AF can use either the procedure for configuring the (g)PTP instance in 5GS as described in clause 4.15.9.3 or the procedure for controlling the 5G access stratum time distribution as described in clause 4.15.9.4 for a particular UE. The procedures are not intended to be used in conjunction with each other by the AF. However, the (g)PTP instance activation, modification and deactivation can influence the 5G AS time distribution for the UEs that are part of the impacted PTP instance.