Question: What happens when an UPLINK GENERIC NAS TRANSPORT message is received from a UE which is in a location where the Public Land Mobile Network (PLMN) is not allowed to operate?
Option 1: The MME forwards the message to the UE's serving gateway.
Option 2: The MME discards the message.
Option 3: The MME sends an error message to the UE.
Option 4: The MME buffers the message for later delivery.
Explanation: According to the NAS protocol, if the MME determines that the UE is in a location where the PLMN is not allowed to operate, it discards the UPLINK GENERIC NAS TRANSPORT message. This ensures that the network does not process messages from unauthorized locations, maintaining security and compliance with regulatory requirements.