PFCP Dictionary (PFCP / N4)¶
A dictionary for looking up the key PFCP messages and forwarding rules used for the control between SMF and UPF (N4). The SMF configures the UPF's behavior with rules.
Related: Protocol Dictionary / N4 page / UPF page / PDU Session chapter
PFCP key messages¶
| Message | Direction | Purpose | Notes | Spec |
|---|---|---|---|---|
| PFCP Association Setup Request/Response | SMF⇔UPF | Establish inter-node association | The inter-node association that is a prerequisite for session control | TS 29.244 |
| PFCP Session Establishment Request/Response | SMF→UPF | Establish a session | Initially configures PDR/FAR, etc. PDU Session chapter | TS 29.244 |
| PFCP Session Modification Request/Response | SMF→UPF | Modify a session | Rule update (PDU Modification/Release) | TS 29.244 |
| PFCP Session Deletion Request/Response | SMF→UPF | Delete a session | Session release | TS 29.244 |
| PFCP Session Report Request/Response | UPF→SMF | Report | Usage reporting (URR) and event notification (such as the DL data arrival notification in the Paging chapter) | TS 29.244 |
| PFCP Heartbeat Request/Response | SMF⇔UPF | Liveness monitoring | Liveness check between nodes | TS 29.244 |
Forwarding rules (Rules)¶
| Rule | Full name | Role |
|---|---|---|
| PDR | Packet Detection Rule | Packet detection conditions (identifies which packets are the target) |
| FAR | Forwarding Action Rule | Specifies forwarding/discard/buffer action |
| QER | QoS Enforcement Rule | QoS enforcement (rate limiting, etc.) |
| URR | Usage Reporting Rule | Usage measurement/charging (N40 coordination) |
| BAR | Buffering Action Rule | Control of buffering action |
(All from TS 29.244)