Section: 4.6.2.3 Provision of NSSAI to lower layers in 5GMM-IDLE mode
Content: 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 subclauses 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 The UE shall store the NSSAI inclusion mode: a) indicated by the AMF, if the AMF included the NSSAI inclusion mode IE in the REGISTRATION ACCEPT message; or b) if the AMF did not include the NSSAI inclusion mode IE in the REGISTRATION ACCEPT message: 1) if the UE is pre-configured by operator to operate by default to according to mode C in the HPLMN (see the DefaultNSSAIInclusionMode leaf of the NAS configuration MO in 3GPP TS 24.368[ Non-Access Stratum (NAS) configuration Management Object (MO) ]  [17] or the USIM file EFNASCONFIG in 3GPP TS 31.102[ Characteristics of the Universal Subscriber Identity Module (USIM) application ]  [22]), then mode C; 2) otherwise: i) mode D for 3GPP access and trusted non-3GPP access; or ii) 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: a) no NSSAI if the UE is performing the registration procedure over 3GPP access; or b) 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.