Question: What action should a Traffic Detection Function (TDF) take when it needs to send a TDF Session update request to a Policy and Charging Rules Function (PCRF) that is known to have restarted since the TDF Session establishment?
Option 1: Send the TDF Session update request to an alternative PCRF.
Option 2: Buffer the update request until the PCRF confirms its restoration.
Option 3: Ignore the need for an update, assuming the new PCRF session will handle it.
Option 4: Refrain from sending the TDF Session update request and may clean up related TDF session information.
Explanation: This is because, according to the specified behavior in case of a known PCRF restart, the TDF should not send the update to prevent potential inconsistencies. Cleaning up related TDF session information is also permissible as part of this process, which aligns with managing resources efficiently post-PCRF restart. This approach ensures that application traffic control on the PDN connection is removed without affecting the PDN connection's state, relying on the PCEF for corresponding cleanup actions.