Question: Which of the following statements is TRUE regarding the detection and handling of requests that have timed out at the originating entity in a 3GPP Evolved Packet System (EPS)?
Option 1: The procedure requires only the originating entities (e.g., MME, SGSN) to be NTP synchronized.
Option 2: Both originating entities (e.g., MME, SGSN, TWAN, ePDG) and receiving entities (e.g., SGW, PGW, PCRF, 3GPP AAA Server) shall be NTP synchronized for this procedure to work effectively.
Option 3: This procedure is exclusively used between entities of different Public Land Mobile Networks (PLMNs) with no operator policy restrictions.
Option 4: The use of this procedure overrides the setting of retransmission timers by intermediate entities like the SGW.
Explanation: For the detection and handling of timed-out requests to work seamlessly, synchronization is crucial. Since both the sender and receiver need a common time reference to accurately determine timeouts, it's logical that both originating and receiving entities must be synchronized using NTP (Network Time Protocol) for consistency in timekeeping across all involved network elements, facilitating effective timeout handling.