Question: What action does an MME (Mobility Management Entity) take upon receiving a UPLINK UE ASSOCIATED LPPA (Location Services Protocol A) TRANSPORT message with an unknown Routing ID for the UE (User Equipment)?
Option 1: The MME sends a failure notification to the eNodeB and then ignores the message.
Option 2: The MME attempts to resolve the Routing ID through a secondary lookup process before taking further action.
Option 3: The MME immediately responds with an error message to the source of the LPPA TRANSPORT message.
Option 4: The MME ignores the message.
Explanation: According to standard procedures for handling abnormal conditions, if an MME receives a UPLINK UE ASSOCIATED LPPA TRANSPORT message with an unknown Routing ID for the UE, the prescribed action is for the MME to ignore the message. This prevents potential processing errors or security vulnerabilities, ensuring network stability and security until the issue can be resolved through other means.