5.27.1.2.1 Distribution of 5G internal system clock

The 5G internal system clock shall be traceable to a common time reference if any of time synchronization services as described in clause 5.27.1.1 is applied. The 5G internal system clock, shall be traceable to a common time reference. The 5G internal system clock shall be made available to all user plane nodes in the 5G system. The UPF and NW-TT may get the common time reference via the underlying PTP compatible transport network with mechanisms outside the scope of 3GPP. The common time reference be made available to UE with signalling of time information related to absolute timing of radio frames as described in TS 38.331 [28]. The 5G internal system clock shall be made available to DS-TT by the UE.