Question: During a subscriber's registration on a Visited Public Land Mobile Network (VPLMN), how does the Home Location Register (HLR) transfer relevant Localised Service Area (LSA) subscription data to the Visited Location Register (VLR)?
Option 1: Via a dedicated LSA Update protocol, separate from standard subscriber data updates.
Option 2: By adding the LSA information to the MAP_INSERT_SUBSCRIBER_DATA and MAP_DELETE_SUBSCRIBER_DATA messages.
Option 3: Through periodic bulk transfers of all subscription data, including LSA information, at set intervals.
Option 4: Only when explicitly requested by the VLR during the registration process.
Explanation: This is the correct method as per the provided context. Adding LSA information to the existing MAP_INSERT_SUBSCRIBER_DATA and MAP_DELETE_SUBSCRIBER_DATA messages ensures efficient and standardized transfer of relevant data between HLR and VLR, especially during subscriber registration or updates in subscription data.