Section: 4.3.1.1 NG User Plane
Content: The NG user plane interface (NG-U) is defined between the NG-RAN node and the UPF. The user plane protocol stack of the NG interface is shown on Figure 4.3.1.1-1. The transport network layer is built on IP transport and GTP-U is used on top of UDP/IP to carry the user plane PDUs between the NG-RAN node and the UPF. Figure 4.3.1.1-1: NG-U Protocol Stack NG-U provides non-guaranteed delivery of user plane PDUs between the NG-RAN node and the UPF. Further details of NG-U can be found in TS 38.410[ NG-RAN; NG general aspects and principles ]  [16].