Section: 14.4 Decorated NAI
Content: The Decorated NAI shall take the form of a NAI and shall have the form '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 draft 2486-bisRFC 4282 [53]. 'Homerealm' is the realm as specified in clause 14.2, using the HPLMN ID ('homeMCC' + 'homeMNC)'. 'Otherrealm' is the realm built using the PLMN ID (visitedMCC + visited MNC) of the PLMN selected as a result of WLAN PLMN selection (see 3GPP TS 24.234[ 3GPP system to Wireless Local Area Network (WLAN) interworking; WLAN User Equipment (WLAN UE) to network protocols; Stage 3 ]  [48]). The username part format of the Root NAI shall comply with IETF RFC 4187 [50] when EAP AKA authentication is used and with IETF RFC 4186 [51], when EAP SIM authentication is used. When the username part of Decorated NAI includes the IMSI, it shall be built following the same steps specified for Root NAI in clause 14.3. The result will be a decorated NAI of the form: "wlan.mnc<homeMNC>.mcc<homeMCC>.3gppnetwork.org !0<IMSI>@wlan.mnc<visitedMNC>.mcc<visitedMCC>.3gppnetwork.org", for EAP AKA authentication and " wlan.mnc<homeMNC>.mcc<homeMCC>.3gppnetwork.org !1<IMSI>@wlan.mnc<visitedMNC>.mcc<visitedMCC>.3gppnetwork.org ", for EAP SIM authentication For example, for EAP AKA authentication: If 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 wlan.mnc015.mcc234.3gppnetwork.org!0234150999999999@wlan.mnc071.mcc610.3gppnetwork.org. NOTE: the 'otherrealm' specified in the present document is resolved by the WLAN AN. If the WLAN AN does not have access to the GRX, then the WLAN AN should resolve the realm by other means e.g. static look-up table, private local DNS server acting as an authoritative name server for that sub-domain.