3GPP 23.501 v20.2.0 — the document's own text
6.3.12b Access Network selection for 5G NSWO
Taught in 6. How one function finds another (The 5G system architecture, in depth).
In addition to the PLMN lists specified in clause 6.3.12 and in clause 6.3.12a, a WLAN access network may also advertise the following PLMN list:
- A PLMN List-5, which includes candidate PLMNs with which "AAA connectivity to 5GC" is supported. A WLAN access network supports "AAA connectivity to 5GC" in a candidate PLMN when it deploys an AAA function that can connect with a NSWOF in this PLMN or can connect with a NSWOF in another PLMN (i.e. HPLMN in roaming case) via AAA proxy. The NSWOF supports "WLAN connection using 5G credentials without 5GS registration", as defined in clause 4.2.15.
If the UE selects a PLMN that is neither UE's HPLMN nor EHPLMN through which the NSWO request should be sent towards the HPLMN, the UE shall use the decorated NAI format as specified in clause 4.2.15 and in TS 23.003 [19].
For access to SNPN or CH , a WLAN access network may also advertise the following SNPN list:
- A SNPN List-5, which includes SNPNs with which "AAA connectivity to 5GC" is supported. The SNPNs are the candidate serving SNPNs that the WLAN access network can connect with. A WLAN access network supports "AAA connectivity to 5GC" in a SNPN when it deploys an AAA function that can connect with a NSWOF in this SNPN or can connect with a NSWOF or AAA server in a CH via AAA Proxy. The SNPN or CH supports "WLAN connection using 5G credentials without 5GS registration", as defined in clause 4.2.15.
NOTE: The selected SNPN within the SNPN List-5 is interpreted as serving SNPN when the SNPN does not correspond to UE's subscribed SNPN.
When the UE wants to connect to a WLAN access network using the 5G NSWO procedure defined in TS 33.501 [29], Annex S, the UE may retrieve the PLMN List-5 or SNPN List-5 advertised by each discovered WLAN access network and may consider this list for selecting the WLAN access network to connect to. For example, if the UE identifies that the HPLMN or CH is included in the PLMN List-5 or SNPN List-5 advertised by a WLAN access network, the UE may select this WLAN access network to connect to using the 5G NSWO procedure.
When the UE is configured by HPLMN or CH to use 5G NSWO for connecting to WLAN access networks using its 5G credentials (as defined in TS 33.501 [29]), the UE shall attempt to select a WLAN that supports 5G NSWO and shall only use the 5G NSWO procedure for connecting to the selected WLAN.
A WLAN access network may also advertise a list of SNPNs which includes SNPNs with which "AAA connectivity to 5GC" is supported. A WLAN access network supports "AAA connectivity to 5GC" in an SNPN when it deploys an AAA function that can connect with a SNPN or CH using any of the architectures defined in clause 4.2.15. When the UE operating in SNPN access mode wants to connect to a WLAN access network using the 5G NSWO procedure defined in Annex S of TS 33.501 [29], the UE may retrieve the SNPNs with which "AAA connectivity to 5GC" is supported that are advertised by each discovered WLAN access network and may consider this information for selecting the WLAN access network to which it attempts to connect.