Question: Upon receiving an SGsAP-EPS-DETACH-INDICATION message, what action does a Visitor Location Register (VLR) take with its implicit detach timer if it was already running?
Option 1: Reset and restart the implicit detach timer to ensure synchronization with the Mobility Management Entity (MME).
Option 2: Stop the implicit detach timer as the detachment for EPS services is already in progress.
Option 3: Continue running the implicit detach timer without any adjustments, as the received message does not affect its state.
Option 4: Immediately trigger a detach procedure for all associated User Equipment (UE).
Explanation: According to the specified behavior, if the VLR’s implicit detach timer is already running, the reception of an SGsAP-EPS-DETACH-INDICATION message does not affect the VLR’s implicit detach timer. This means the timer continues to run without any adjustments, ensuring existing procedures are not interrupted by potentially redundant detachment indications.