5.36 Paging Policy Indicator Provisioning

29.2443GPPInterface between the Control Plane and the User Plane nodesRelease 17TS

5.36.1 General

Stage 2 requirements for Paging Policy Differentiation are specified in clause 5.4.3.2 of 3GPP TS 23.501 [28].

For a UE in RRC Inactive state the NG-RAN can be required to enforce specific paging policies in the case of NG-RAN paging, based on 5QI, ARP and PPI associated with an incoming DL PDU. To support this, the SMF shall instruct the UPF to detect the DSCP in the TOS (IPv4) / TC (IPv6) value in the IP header of the DL PDU and insert the corresponding PPI as described below. When Paging Policy Differentiation is enabled in the network and a PPI needs to be inserted into DL PDU, the SMF shall:

– provision a PDR for each PPI containing one or more DSCP code(s) to be matched against the DSCP in the TOS (IPv4) / TC (IPv6) value in the IP header of the DL PDUs, where these DSCP code(s) are to be mapped to the same PPI, in the PDI together with or without the service data flow detection information;

NOTE 1: When service data flow level packet detection is not required, e.g. for an I/V-UPF, the PDR can be provisioned with one or more DSCP(s) to be matched in the PDI without any service data flow detection information.

NOTE 2: When service data flow level packet detection is required, several PDRs with the same service data flow detection information but with different (set of) DSCP(s) (which are mapped to different PPI) need to be provisioned.

– associate the PDR with a QER with the Paging Policy Indicator set to the mapped PPI to instruct UPF to insert the corresponding PPI into the GTP-U PDU Session Container extension header of outgoing packets.

5.36.2 Enhanced Paging Policy Indicator Provisioning

To reduce the number of PDRs/QERs to be provisioned (in order to support NG-RAN paging using Paging Policy Indicator (PPI)), the SMF and the UPF may support the Enhanced Provisioning Paging Policy Indicator (EPPPI) feature as specified below.

During a PFCP session establishment/modification procedure, if both the SMF and the UPF support the EPPPI feature, the SMF may include a DSCP to PPI Control Information in the PFCP Session Establishment/Modification Request message to instruct the UPF to insert a PPI in the GTP-U PDU Session Container extension header of downlink GTP-U packets encapsulating payload packets (to be sent to the UE). When the DSCP to PPI Control Information IE is present, the SMF may:

– include one or more DSCP to PPI Mapping Information to instruct the UPF to insert the corresponding PPI for downlink GTP-U packets, where the DSCP of its payload packet is matching one of DSCP codes in the DSCP to PPI Mapping Information;

– include one or more QFIs to instruct UPF to insert PPI only for the downlink packets received on the requested QFI(s);