3GPP 23.501 v20.2.0 — the document's own text
5.30.2.9.1 General
Taught in 24. Networks that are not for everybody (The 5G system architecture, in depth).
SNPNs may support UE access using credentials owned by a Credentials Holder separate from the SNPN. In this case the Session Management procedures (i.e. PDU Sessions) terminate in an SMF in the SNPN.
When an SNPN supports UE access using credentials assigned by a Credentials Holder separate from the SNPN, it is assumed that is supported homogeneously within the whole SNPN.
Credentials Holder using AAA Server for primary authentication and authorization is described in clause 5.30.2.9.2 and Credentials Holder using AUSF and UDM for primary authentication and authorization is described in clause 5.30.2.9.3.