Question: What is the correct format for deriving a Home Network Domain Name from an IMSI when the Mobile Network Code (MNC) is 2 digits long, and how should it be structured?
Option 1: ocs.mnc<MNC>.mcc<MCC>.3gppnetwork.org without any modifications to the MNC length
Option 2: ocs.mnc0<MNC>.mcc<MCC>.3gppnetwork.org adding a zero at the end of the MNC
Option 3: ocs.<MNC>mnc.mcc<MCC>.3gppnetwork.org rearranging the order and omitting the 'mnc' prefix for the MNC value
Option 4: ocs.mnc0<MNC>.mcc<MCC>.3gppnetwork.org adding a zero at the beginning of the MNC to make it 3 digits long
Explanation: According to the specifications, if the MNC of the PLMN is 2 digits, then a zero shall be added at the beginning to derive the Home Network Domain Name from an IMSI. This ensures consistency in formatting, making all MNC representations 3 digits long for this purpose. The correct structure, therefore, includes adding a leading zero to the 2-digit MNC, as shown in Option 4.