3GPP 23.501 v20.2.0 — the document's own text
4.3.2 Roaming architecture
Taught in 18. Being served by somebody else's network (The 5G system architecture, in depth), 19. Living next to 4G (The 5G system architecture, in depth), 7. Roaming, other accesses, the edge and the outside (The 5G system architecture, overview).
Figure 4.3.2-1 represents the Roaming architecture with local breakout and Figure 4.3.2-2 represents the Roaming architecture with home-routed traffic for interworking between 5GS and EPC/E-UTRAN.
NOTE 1: There can be another UPF (not shown in the figure above) between the NG-RAN and the UPF + PGW-U, i.e. the UPF + PGW-U can support N9 towards the additional UPF, if needed.
NOTE 2: S9 interface from EPC is not required since no known deployment exists.
