Section: 28.7.6 NAI used for 5G registration via trusted non-3GPP access
Content: While performing the EAP-authentication procedure when a UE attempts to register to 5GCN via a trusted non-3GPP access network in a selected PLMN (see clause 4.12a in 3GPP TS 23.502[ Procedures for the 5G System (5GS) ]  [120]), the UE shall derive a NAI from the identity of the selected PLMN in the following format: "<any_non_null_string>@nai.5gc.mnc<MNC>.mcc<MCC>.3gppnetwork.org" where: a) the username part <any_non_null_string> is any non null string; and b) the <MNC> and <MCC> identify the PLMN (either HPLMN or VPLMN) to which the UE attempts to connect via the trusted non-3GPP access network as described in clause 6.3.12 in 3GPP TS 23.501[ System architecture for the 5G System (5GS) ]  [119]. While performing the EAP-authentication procedure when a UE attempts to register to 5GCN via a trusted non-3GPP access network in a selected SNPN (see clause 5.30.2.13 in 3GPP TS 23.501[ System architecture for the 5G System (5GS) ]  [119]), the UE shall derive a NAI from the identity of the selected SNPN in the following format: "<any_non_null_string>@nai.5gc.nid<NID>.mnc<MNC>.mcc<MCC>.3gppnetwork.org"; where: a) the username part <any_non_null_string> is any non null string; and b) the <MNC>, <MCC> and <NID> identify the SNPN to which the UE attempts to connect via the trusted non-3GPP access network. While performing the EAP authentication procedure when a UE attempts to register to 5GCN via a trusted non-3GPP access network in a selected TNGF, the UE shall derive NAI from the identity of the selected TNGF in the following format: "<any_non_mull_string>@tngfid<TNGF ID>.nai.5gc.mnc<MNC>.mcc<MCC>.3gppnetwork.org"; where: a) The username part <any_non_mull_string> is any non null string; and b) The <MNC> and <MCC> identify the PLMN (either HPLMN or VPLMN) to which the UE attempts to connect via the trusted non-3GPP access network; and c) <TNGF ID> identifies the TNGF. The TNGF ID value shall comply with the syntax specified in clause 2.2 of IETF RFC 7542 [126] for a label in the realm part of a NAI. While performing the EAP-authentication procedure when a UE attempts to register to 5GCN via a trusted non-3GPP access network in a selected SNPN and TNGF, the UE shall derive a NAI from the identity of the selected SNPN and TNGF in the following format: "<any_non_null_string>@tngfid<TNGF ID>.nai.5gc.nid<NID>.mnc<MNC>.mcc<MCC>.3gppnetwork.org"; where: a) the username part <any_non_null_string> is any non null string; and b) the <MNC>, <MCC> and <NID> identify the SNPN to which the UE attempts to connect via the trusted non-3GPP access network; and c) <TNGF ID> identifies the TNGF. The TNGF ID value shall comply with the syntax specified in clause 2.2 of IETF RFC 7542 [126] for a label in the realm part of a NAI. NOTE 1: The username part of the NAI is not used to identify the UE since the UE is identified by its NAS registration to the 5GCN independent of using the NAI. The realm part of the NAI is however used by the trusted non-3GPP access for TNGF selection. NOTE 2: In case of 5GCN, there is no need for a decorated NAI as in EPC (see clause 19.3.3), since the UE sends a NAS registration request to the PLMN including a SUCI or 5G-GUTI.