5.7.1.7 UL Traffic

Following characteristics apply for processing of UL traffic:

• UE uses the stored QoS rules to determine mapping between UL User Plane traffic and QoS Flows. UE marks the UL PDU with the QFI of the QoS rule containing the matching Packet Filter and transmits the UL PDUs using the corresponding access specific resource for the QoS Flow based on the mapping provided by (R)AN. For NG-RAN, the UL behaviour is specified in clause 10.5.2 of TS 38.300 [27].
• (R)AN transmits the PDUs over N3 tunnel towards UPF. When passing an UL packet from (R)AN to CN, the (R)AN includes the QFI value, in the encapsulation header of the UL PDU and selects the N3 tunnel.
• (R)AN performs transport level packet marking in the UL on a per QoS Flow basis with a transport level packet marking value that is determined based on the 5QI, the Priority Level (if explicitly signalled) and the ARP priority level of the associated QoS Flow.
• UPF verifies whether QFIs in the UL PDUs are aligned with the QoS Rules provided to the UE or implicitly derived by the UE in the case of Reflective QoS).
• UPF and UE perform Session-AMBR enforcement as specified in clause 5.7.1.8 and the UPF performs counting of packets for charging.