3GPP 23.501 v20.2.0 — the document's own text
8.2.5 Control Plane for trusted non-3GPP Access
Taught in 8. What actually travels on the wire (The 5G system architecture, in depth).


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

In the above figures 8.2.5-2 and 8.2.5-3, the UDP protocol may be used between the UE and TNGF to enable NAT traversal for IKEv2 and IPsec traffic.
The NWt connection is defined in clause 4.2.8.3 and in clause 4.12a.2.2 of TS 23.502 [3].