Question: What action does the MME take upon receiving a PDN DISCONNECT REQUEST message that is accepted by the network?
Option 1: The MME sends a DEACTIVATE EPS BEARER CONTEXT ACCEPT message to the UE.
Option 2: The MME initiates the bearer context deactivation procedure by sending a DEACTIVATE EPS BEARER CONTEXT REQUEST message to the UE.
Option 3: The MME releases all resources reserved for the PDN in the network immediately.
Option 4: The MME stops the timer T3492 and enters the state PROCEDURE TRANSACTION INACTIVE.
Explanation: When a PDN DISCONNECT REQUEST message is accepted by the network, the MME's next step is to initiate the bearer context deactivation procedure. This involves sending a DEACTIVATE EPS BEARER CONTEXT REQUEST message that includes the linked EPS bearer identity of the default bearer associated with the PDN to disconnect from and the PTI (Procedure Transaction Identity).