Section: 19.3.3 Decorated NAI
Content: The Decorated NAI shall take the form of a NAI and shall have the form 'homerealm!username@otherrealm' or 'Visitedrealm!homerealm!username@otherrealm' as specified in clause 2.7 of the IETF RFC 4282 [53]. The realm part of Decorated NAI consists of 'otherrealm', see the IETF RFC 4282 [53]. 'Homerealm' is the realm as specified in clause 19.2, using the HPLMN ID ('homeMCC' + 'homeMNC)'. 'Visitedrealm' is the realm built using the VPLMN ID ('VisitedMCC' + 'VisitedMNC)', 'Otherrealm' is: - the realm built using the PLMN ID (visitedMCC + visited MNC) if the service provider selected as a result of the service provider selection (see 3GPP TS 24.302[ Access to the 3GPP Evolved Packet Core (EPC) via non-3GPP access networks; Stage 3 ]  [77]) has a PLMN ID; or - a domain name of a service provider if the selected service provider does not have a PLMN ID (3GPP TS 24.302[ Access to the 3GPP Evolved Packet Core (EPC) via non-3GPP access networks; Stage 3 ]  [77]). When the username part of Decorated NAI includes the IMSI and the service provider has a PLMN ID, the Decorated NAI shall be built following the same steps as specified for Root NAI in clause 19.3.2. The result will be a decorated NAI of the form: - nai.epc.mnc<homeMNC>.mcc<homeMCC>.3gppnetwork.org !0<IMSI>@nai.epc.mnc<visitedMNC>.mcc<visitedMCC>.3gppnetwork.org for EAP AKA authentication. or - nai.epc.mnc<homeMNC>.mcc<homeMCC>.3gppnetwork.org !6<IMSI>@nai.epc.mnc<visitedMNC>.mcc<visitedMCC>.3gppnetwork.org for EAP AKA' authentication. For example, if the service provider has a PLMN ID and the IMSI is 234150999999999 (MCC = 234, MNC = 15) and the PLMN ID of the Selected PLMN is MCC = 610, MNC = 71, then the Decorated NAI takes the form either as: - nai.epc.mnc015.mcc234.3gppnetwork.org!0234150999999999@nai.epc.mnc071.mcc610.3gppnetwork.org for EAP AKA authentication or - nai.epc.mnc015.mcc234.3gppnetwork.org!6234150999999999@nai.epc.mnc071.mcc610.3gppnetwork.org for EAP AKA' authentication. For example, if the domain name of a service provider is 'realm.org' and IMSI-based permanent username is used, then the Decorated NAI takes the form either as: - nai.epc.mnc<homeMNC>.mcc<homeMCC>.3gppnetwork.org !0<IMSI>@realm.org for EAP AKA authentication or - nai.epc.mnc<homeMNC>.mcc<homeMCC>.3gppnetwork.org !6<IMSI>@realm.org for EAP AKA' authentication. If the UE has selected a WLAN that directly interworks with a service provider in the Equivalent Visited Service Providers (EVSP) list provided by the RPLMN, see 3GPP TS 23.402[ Architecture enhancements for non-3GPP accesses ]  [77], clause 4.8.2b, then the decorated NAI is constructed to include the realm of this service provider and the realm of RPLMN. If the domain name of a service provider is 'realm.org' and IMSI-based permanent username is used, then the Decorated NAI with double decoration takes the form either as: - nai.epc.mnc<rplmnMNC>.mcc<rplmnMCC>.3gppnetwork.org !nai.epc.mnc<homeMNC>.mcc<homeMCC>.3gppnetwork.org!0<IMSI>@realm.org for EAP AKA authentication or - nai.epc.mnc<rplmnMNC>.mcc<rplmnMCC>.3gppnetwork.org !nai.epc.mnc<homeMNC>.mcc<homeMCC>.3gppnetwork.org!6<IMSI>@realm.org for EAP AKA' authentication. When the username part of Decorated NAI includes a Fast Re-authentication NAI, the Decorated NAI shall be built following the same steps as specified for the Fast Re-authentication NAI in clause 19.3.4. When the username part of Decorated NAI includes a Pseudonym, the Decorated NAI shall be built following the same steps as specified for the Pseudonym identity in clause 19.3.5.