Question: In Unsolicited Application Reporting mode, what triggers a Traffic Detection Function - User plane (TDF-U) to communicate with the Traffic Detection Function - Control plane (TDF-C) for application reporting?
Option 1: Periodic timer expiration in TDF-U
Option 2: Receipt of new user data packets from the User Equipment (UE)
Option 3: Change in network congestion levels
Option 4: Instructions provided by TDF-C during the Sx session management procedure indicating a need for application reporting
Explanation: According to the specified behavior for Unsolicited Application Reporting mode, TDF-U communicates with TDF-C for application reporting based on instructions received from TDF-C during the Sx session management procedure. This indicates that the trigger is not periodic, nor solely based on new data packets or network conditions, but rather on explicit instructions from TDF-C regarding when to report.