5.19 Activation and Deactivation of Pre-defined PDRs

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

To reduce the signalling overhead for establishing a PFCP session (for a PDU session or a PDN connection) and improve the signalling efficiency, the CP and UP functions may support the Activation and Deactivation of a Pre-defined PDR (ADPDP) feature as described below.

When both the CP function and the UP function support the ADPDP feature, the CP function may activate one or more pre-defined PDRs for a PFCP session during a PFCP Session Establishment or a PFCP Session Modification procedure. A pre-defined PDR shall be configured in the UP function before it can be activated in a PFCP session.

A pre-defined PDR may contain all the necessary packets detection information to identify a service data flow or application traffic which may be common to many PFCP sessions, and it may be configured in the UPF associated with a pre-defined FAR, one or more pre-defined QER(s), and/or one or more pre-defined URR(s).

Any PFCP session specific information, e.g. traffic endpoint information, may not be part of a pre-defined PDR and is provisioned before or during the activation of the pre-defined PDR.

To activate one or more pre-defined PDR(s), the CP function shall provide one or more Activate Predefined Rules IE(s) in a Create PDR IE in a PFCP Session Establishment Request, or in a Create PDR IE or an Update PDR IE in a PFCP Session Modification Request message, that references a pre-defined PDR configured in the UP function, with the following information in the Create PDR or Update PDR IE:

– the traffic endpoint that the traffic shall match (e.g. Local F-TEID, UE IP Address or Traffic Endpoint ID);

– optionally the QFI that the traffic shall match, e.g. for a UL PDR where UL QoS flow binding verification is required (see clause 5.4.2);

– the precedence to be applied by the UP function among all PDRs of the PFCP session;

– optionally, an FAR containing instructions related to the processing of the packets matching the pre-defined PDR(s); when present, the UP function shall enforce it instead of the one defined in the pre-defined PDR(s) if any;

– optionally, one or more URRs to be used in addition to any URR(s) specified in the pre-defined PDR(s) (e.g. for session level Usage Monitoring);

– optionally, one or more QERs to be applied in addition to any QER(s) specified in the pre-defined PDR (e.g. for APN-AMBR enforcement).

When a pre-defined PDR is activated for a given PDR, an incoming packet matches the PDR if it matches the traffic endpoint, and the QFI if provisioned and one of the activated pre-defined PDR(s).

The CP function may update the use of pre-defined PDRs that are already activated in a PFCP session by including one or more Activate Predefined Rules IE(s) or Deactivate Predefined Rules IE(s) in a PFCP Session Modification Request and/or by updating the parameters provisioned in the PDR.

NOTE: The CP function cannot change a pre-defined PDR via PFCP session related procedure.

The CP function may deactivate a pre-defined PDR that is already activated in a PFCP session by including the Deactivate Predefined Rules IE in a PFCP Session Modification Request requesting to deactivate the predefined PDR(s).

In addition, this feature allows to define a group of pre-defined PDRs which can be activated, updated, and deactivated together. This allows the CP function to further optimize the signaling towards the UP function.

To activate, update, or deactivate a group of pre-defined PDRs, the CP shall follow the same procedure as for activating, updating, and deactivating a pre-defined PDR, but it shall use an Activate Predefined Rules IE that refers to a group of pre-defined PDRs.