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

5.17.7.2.3 Relaying

Taught in 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).

The AMF performs relaying between N2 and N26 messages as described in TS 38.413 [34] and TS 29.274 [101].

The MME performs relaying between S1 and N26 message as described in TS 36.413 [100] and TS 29.274 [101].