Section: 21.2.3 Format of HA-APN Operator Identifier
Content: The HA-APN Operator Identifier is composed of six labels. The last three labels shall be "pub.3gppnetwork.org". The second and third labels together shall uniquely identify the PLMN. The first label distinguishes the domain name as a HA-APN. For each operator, there is a default HA-APN Operator Identifier (i.e. domain name). This default HA-APN Operator Identifier is derived from the IMSI as follows: "ha-apn.mnc<MNC>.mcc<MCC>.pub.3gppnetwork.org" where: "mnc" and "mcc" serve as invariable identifiers for the following digits. <MNC> and <MCC> are derived from the components of the IMSI defined in clause 2.2. Alternatively, the default HA-APN Operator Identifier is derived using the MNC and MCC of the VPLMN. In order to guarantee inter-PLMN DNS translation, the <MNC> and <MCC> coding used in the "ha-apn.mnc<MNC>.mcc<MCC>.pub.3gppnetwork.org" format of the HA-APN OI shall be: - <MNC> = 3 digits - <MCC> = 3 digits If there are only 2 significant digits in the MNC, one "0" digit shall be inserted at the left side to fill the 3 digits coding of MNC in the HA-APN OI. As an example, the HA-APN OI for MCC 345 and MNC 12 is coded in the DNS as: "ha-apn.mnc012.mcc345.pub.3gppnetwork.org".