Question: Upon receiving an SGsAP-EPS-DETACH-ACK message from the VLR, what action does the MME take regarding timer Ts8, and what is its approach to sending a detach confirmation to the UE?
Option 1: The MME starts timer Ts8 and waits for its expiration before sending a detach confirmation to the UE.
Option 2: The MME stops timer Ts8 but only sends a detach confirmation to the UE after receiving the SGsAP-EPS-DETACH-ACK message.
Option 3: The MME stops timer Ts8 and does not wait for the SGsAP-EPS-DETACH-ACK message to send a detach confirmation to the UE if needed.
Option 4: The MME ignores timer Ts8's state and never sends a detach confirmation to the UE after receiving the SGsAP-EPS-DETACH-ACK.
Explanation: This is correct because, upon receiving an SGsAP-EPS-DETACH-ACK from the VLR, the MME stops timer Ts8. If a detach confirmation needs to be sent to the UE, the MME does not delay this action pending receipt of the SGsAP-EPS-DETACH-ACK message, indicating an independent decision-making process for each action based on the received message.