3GPP 24.501 v20.0.0 — the document's own text
4.6.2.3 Provision of NSSAI to lower layers in 5GMM-IDLE mode
The UE NAS layer may provide the lower layers with an NSSAI (either requested NSSAI or allowed NSSAI) when the UE in 5GMM-IDLE mode sends an initial NAS message.
The AMF may indicate, via the NSSAI inclusion mode IE of a REGISTRATION ACCEPT message, an NSSAI inclusion mode in which the UE shall operate over the current access within the current PLMN or SNPN, if any (see clauses 5.5.1.2.4 and 5.5.1.3.4), where the NSSAI inclusion mode is chosen among the following NSSAI inclusion modes described in table 4.6.2.3.1.
Table 4.6.2.3.1: NSSAI inclusion modes and NSSAI which shall be provided to the lower layers
| Initial NAS message | NSSAI inclusion mode A | NSSAI inclusion mode B | NSSAI inclusion mode C | NSSAI inclusion mode D |
|---|---|---|---|---|
| REGISTRATION REQUEST message:i) including the 5GS registration type IE set to "initial registration" | Requested NSSAI, if any | Requested NSSAI, if any | Requested NSSAI, if any | No NSSAI |
| REGISTRATION REQUEST message:i) including the 5GS registration type IE set to "mobility registration updating"; andii) initiated by case other than case g) or n) in clause 5.5.1.3.2 | Requested NSSAI, if any | Requested NSSAI, if any | Requested NSSAI, if any | No NSSAI |
| REGISTRATION REQUEST message:i) including the 5GS registration type IE set to "mobility registration updating"; andii) initiated by case g) or n) in clause 5.5.1.3.2 | Allowed NSSAI, and partially allowed NSSAI, if any | Allowed NSSAI, and partially allowed NSSAI, if any | No NSSAI | No NSSAI |
| REGISTRATION REQUEST message:i) including the 5GS registration type IE set to "periodic registration updating" | Allowed NSSAI, and partially allowed NSSAI, if any | Allowed NSSAI, and partially allowed NSSAI, if any | No NSSAI | No NSSAI |
| SERVICE REQUEST message | Allowed NSSAI, and partially allowed NSSAI, if any | See NOTE 1 | No NSSAI | No NSSAI |
| NOTE 1: All the S-NSSAIs of the PDU sessions that have the user-plane resources requested to be re-established by the service request procedure or the S-NSSAIs of a control plane interaction triggering the service request is related to (see 3GPP TS 23.501 [8])NOTE 2: For a REGISTRATION REQUEST message which is triggered by emergency services, a DEREGISTRATION REQUEST message, and a SERVICE REQUEST message which is triggered by emergency services (e.g. a SERVICE REQUEST message includes the service type IE set to "emergency services" or "emergency services fallback", a SERVICE REQUEST message triggered for emergency services includes the service type IE set to “high priority access” as specified in clause 5.6.1.2.1), no NSSAI is provided to the lower layers. If the UE performs initial registration for onboarding services in SNPN or is registered for onboarding services in SNPN, the UE NAS layer shall not provide the lower layers with an NSSAI.NOTE 3: The mapped configured S-NSSAI(s) from the S-NSSAI(s) of the HPLMN are not included as part of the S-NSSAIs in the requested NSSAI or the allowed NSSAI when it is provided to the lower layers. |
The UE shall store the NSSAI inclusion mode:
- indicated by the AMF, if the AMF included the NSSAI inclusion mode IE in the REGISTRATION ACCEPT message; or
- if the AMF did not include the NSSAI inclusion mode IE in the REGISTRATION ACCEPT message:
- if the UE is pre-configured by operator to operate by default to according to mode C in the HPLMN (if the EHPLMN list is not present or is empty) or EHPLMN (if the EHPLMN list is present), (see the DefaultNSSAIInclusionMode leaf of the NAS configuration MO in 3GPP TS 24.368 [17] or the USIM file EFNASCONFIG in 3GPP TS 31.102 [22]), then mode C;
- otherwise:
- mode D for 3GPP access and trusted non-3GPP access; or
- mode B for untrusted non-3GPP access and wireline access,
together with the identity of the current PLMN or SNPN and access type in a non-volatile memory in the ME as specified in annex C.
The UE shall apply the NSSAI inclusion mode received in the REGISTRATION ACCEPT message over the current access within the current PLMN and its equivalent PLMN(s), if any, or the current SNPN in the current registration area.
When a UE performs a registration procedure to a PLMN which is not a PLMN in the current registration area or an SNPN, if the UE has no NSSAI inclusion mode for the PLMN or the SNPN stored in a non-volatile memory in the ME, the UE shall provide the lower layers with:
- no NSSAI if the UE is performing the registration procedure over 3GPP access; or
- requested NSSAI if the UE is performing the registration procedure over non-3GPP access.
When a UE performs a registration procedure after an inter-system change from S1 mode to N1 mode, if the UE has no NSSAI inclusion mode for the PLMN stored in a non-volatile memory in the ME and the registration procedure is performed over 3GPP access, the UE shall not provide the lower layers with any NSSAI over the 3GPP access.