29.2443GPPInterface between the Control Plane and the User Plane nodesRelease 17TS
This clause specifies the support of uplink packets buffering.
5.32.2 Uplink packets buffering for on-line charging
If the UP function indicated support of the Quota Action (QUOAC) feature in the UP Function Features IE and the FAR ID for Quota Action was set to buffer the application traffic at zero quota, the UP function shall buffer the related uplink packets if it is provisioned with zero quota earlier or the quota has been exhausted, as specified in clause 220.127.116.11.1. In addition, if the UP Function has indicated support of the feature UL/DL Buffering Control (UDBC), the UP function shall buffer the number of packets (including both uplink or downlink) based on the Suggested Buffering Packet Count IE in a BAR provided by the SMF, until it receives new instructions from the CP function, e.g. when the new Quota is granted.
5.32.3 Uplink packets buffering during EAS relocation
If the UP function supports uplink packets buffering during EAS relocation, the UP function shall set the UPBER bit in the UP Function Features (see clause 8.2.25).
The SMF shall request the UPF (PSA) to buffer the uplink packets related to one or more Service Data Flows sent to the new EAS by setting the BUFF flag in Apply Action IE of the related FAR. The SMF shall set the FORW flag in Apply Action IE when the EAS relocation has been performed.
Editor’s Note: Whether additional mechanism to instruct UP function to allocate UP buffering resource and to report the failure of buffering during EAS relocation is FFS.