Section: 14.2 Home network realm
Content: The home network realm shall be in the form of an Internet domain name, e.g. operator.com, as specified in RFC 1035 [19]. When attempting to authenticate within WLAN access, the WLAN UE shall derive the home network domain name from the IMSI as described in the following steps: 1. take the first 5 or 6 digits, depending on whether a 2 or 3 digit MNC is used (see 3GPP TS 31.102[ Characteristics of the Universal Subscriber Identity Module (USIM) application ]  [27], 3GPP TS 51.011[ Specification of the Subscriber Identity Module - Mobile Equipment (SIM-ME) interface ]  [66]) and separate them into MCC and MNC; if the MNC is 2 digits then a zero shall be added at the beginning; 2. use the MCC and MNC derived in step 1 to create the "mnc<MNC>.mcc<MCC>. 3gppnetwork.org" domain name; 3. add the label "wlan." to the beginning of the domain name. An example of a WLAN NAI realm is: IMSI in use: 234150999999999; Where: MCC = 234; MNC = 15; MSIN = 0999999999 Which gives the home network domain name: wlan.mnc015.mcc234.3gppnetwork.org. NOTE: If it is not possible for the WLAN UE to identify whether a 2 or 3 digit MNC is used (e.g. SIM is inserted and the length of MNC in the IMSI is not available in the "Administrative data" data file), it is implementation dependent how the WLAN UE determines the length of the MNC (2 or 3 digits).