The purpose of the Transfer of DL PDU Session Information procedure is to send control information elements related to the PDU Session from UPF to NG-RAN.
In the case of uplink and downlink data forwarding the DL PDU Session Information procedure shall also be used to send control information elements related to the PDU Session from NG-RAN node to UPF, or from UPF to NG-RAN node, or between NG-RAN nodes.
A PDU Session user plane instance making use of the Transfer of DL PDU Session Information procedure is associated to a single PDU Session. The Transfer of DL PDU Session Information procedure may be invoked whenever packets for that particular PDU Session need to be transferred across the related interface instance.
The DL PDU SESSION INFORMATION frame includes a QoS Flow Identifier (QFI) field associated with the transferred packet. The NG-RAN shall use the received QFI to determine the QoS flow and QoS profile which are associated with the received packet.
The DL PDU SESSION INFORMATION frame shall include the Reflective QoS Indicator (RQI) field to indicate whether user plane Reflective QoS shall be activated or not. The NG-RAN shall, if RQA has been configured for the involved QoS flow as specified in
TS 38.413, take the RQI into account as specified in
TS 37.324.
The DL PDU SESSION INFORMATION frame may also include a Paging Policy Indicator (PPI) field associated with the transferred packet. The NG-RAN shall use the received PPI to determine the paging policy differentiation which is associated with the received packet as described in
TS 23.501.
The DL PDU SESSION INFORMATION frame may also include a QoS Monitoring Packet (QMP) field and a DL sending time stamp field. The NG-RAN shall, if QoS monitoring has been configured for the included QFI field, perform delay measurement and QoS monitoring, as specified in
TS 23.501.
The DL PDU SESSION INFORMATION frame may also include a DL QFI Sequence Number field associated with the transferred packet. The NG-RAN shall, if the QoS flow has been configured eligible for redundant transport bearer in
TS 38.413, use the received DL QFI Sequence Number field to determine and eliminate duplicated packets for a given QoS flow as specified in
TS 23.501.
The DL PDU SESSION INFORMATION frame may also include a DL MBS QFI Sequence Number field associated with the transferred packet. The NG-RAN shall use the received DL MBS QFI Sequence Number field to determine the PDCP count that should be used when transferring the packet over the radio as specified in
TS 38.300.
When needed, the NG-RAN shall propagate the DL PDU Session Information to a peer NG-RAN.
Void.