If the User Plane Function indicates the support of the feature UL or DL Buffering Control (UDBC), the SMF provides the buffering packet count IE in a BAR. The buffering count IE is created during a PFCP Session Establishment procedure or a PFCP Session Modification procedure. The SMF modifies it in a subsequent PFCP session modification request, "and" or "or" a PFCP Session Report Response message. The same BAR associates with all the FARs in a PFCP session to indicate that all service data flows in the PFCP session shares the same buffer in the UPF for the PFCP session. One BAR is created per PFCP session.

The SMF provisions multiple buffering parameters in a BAR. It is in Create BAR or Update BAR in various PFCP messages.

Currently, UPF supports the following IE:

• The suggested buffering packet count IE - If the UPF indicates the support of the feature UDBC to indicate the number of packets. It includes both uplink or downlink that the SMF suggests buffering in the UPF, until it receives new instructions from the SMF. Example: when the new quota is granted.

• DL buffering suggested packet count IE – This IE is received with update BAR from SMF in Session Report Response message, if SMF wants more DL packets to be buffered on UPF.

The UPF does not apply the DL buffering duration and DL buffering suggested packet count parameters and deletes these parameters from the BAR (without explicit request from the SMF) when extended buffering of downlink data packets ends in the UPF. The UPF does not apply buffering when it receives the new instruction from the SMF. The buffered packets are either dropped or forwarded following the packet forwarding model and considering that the buffered packets are already processed earlier.

The SMF sends the PPI value in Create QER or Update QER, if UPF needs to set Paging Policy Indicator in outgoing PDU packets.