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

5.30.2.6 Cell (re-)selection in SNPN access mode

Taught in 24. Networks that are not for everybody (The 5G system architecture, in depth).

UEs operating in SNPN access mode only select cells and networks broadcasting both PLMN ID and NID of the selected SNPN or its equivalent SNPN.

NOTE: Further details on the NR idle and inactive mode procedures for SNPN cell selection is defined in TS 38.331 [28] and in TS 38.304 [50].