Gating Control

Gating Control in the UPF enables or disables the forwarding of IP packets belonging to a service data flow or detected application's traffic to pass through to the desired endpoint. See 3GPP TS 23.203, subclause 4.3.2.

The SMF controls the gating in the UPF by creating PDRs for the service data flow(s) or application's traffic to be detected, and by associating a QER, including the Gate Status IE, to the PDRs.

The Gate Status IE indicates whether the service data flow or detected application traffic is allowed to be forwarded (the gate is open) or to be discarded (the gate is closed) in the uplink and/or in downlink directions.

The UPF identifies the UL and DL flows by the Source Interface IE in the PDI of the PDRs or the destination Interface IE in the FARs. The UPF applies UL and DL gating accordingly.

The SMF requests the UPF to discard the packets that are received for the PDR by setting the gate fields in the Gate Status IE of QERs to CLOSED.