School of Specs 23.501v20.2.0

3GPP 23.501 v20.2.0 — the document's own text

8.2.4 Control Plane for untrusted non 3GPP Access

Taught in 8. What actually travels on the wire (The 5G system architecture, in depth).

Figure 8.2.4-1: Control Plane before the signalling IPsec SA is established between UE and N3IWF
Figure 8.2.4-1: Control Plane before the signalling IPsec SA is established between UE and N3IWF
Figure 8.2.4-2: Control Plane after the signalling IPsec SA is established between UE and N3IWF
Figure 8.2.4-2: Control Plane after the signalling IPsec SA is established between UE and N3IWF

Large NAS messages may be fragmented by the "inner IP" layer or by TCP.

Figure 8.2.4-3: Control Plane for establishment of user-plane via N3IWF
Figure 8.2.4-3: Control Plane for establishment of user-plane via N3IWF

In the above figures 8.2.4-1, 8.2.4-2 and 8.2.4-3, the UDP protocol may be used between the UE and N3IWF to enable NAT traversal for IKEv2 and IPsec traffic.

The "signalling IPsec SA" is defined in clause 4.12.2 of TS 23.502 [3].