3GPP 23.501 v20.2.0 — the document's own text
5.8.2.5.1 General
Taught in 13. Where the packets actually go (The 5G system architecture, in depth), 5. The connection, and what is promised on it (The 5G system architecture, overview).
The SMF controls user-plane packet forwarding for traffic detected by a PDR by providing a FAR with instructions to the UPF, including:
- Forwarding operation information;
- Forwarding target information.
The details of the forwarding target and operation will depend on the scenario and is described below. The following forwarding functionality is required by the UPF:
- Apply N3 /N9 tunnel related handling, i.e. encapsulation.
- Forward the traffic to/from the SMF, e.g. as described in Table 5.8.2.5.2-1.
- Forward the SM PDU DN Request Container from SMF to DN-AAA server
- Forward the traffic according to locally configured policy for traffic steering.
- Forward the traffic according to N4 rules of a 5G VN group for 5G VN group communication.
- Forward the traffic to/from the EASDF.
Data forwarding between the SMF and UPF is transmitted on the user plane tunnel established on N4 interface, defined in TS 29.244 [65].