A network administrator configures a Cisco IOS router to synchronize its time with an upstream NTP server operating at Stratum 2. Arrange the following steps in the correct chronological order from the initial synchronization attempt to successful time synchronization on the router.
- 1The router transmits an NTP client request packet destined to UDP port 123 on the NTP server.
- 2The NTP server replies with an NTP packet containing its current reference timestamp and a Stratum level of 2.
- 3The router processes the received timestamps to compute the network round-trip delay and local clock offset.
- 4The router updates its local system clock and assumes a Stratum level of 3.
- 5The router marks the NTP server association with an asterisk () in the output of the `show ntp associations` command.
Answer
The correct sequence starts with transmitting the NTP request packet (UDP 123), followed by receiving the server response with Stratum 2 details, calculating offset and delay, updating the local clock to Stratum 3, and finally marking the peer association as synchronized ().
The NTP synchronization process must follow a logical operational sequence: first, sending a client poll via UDP port 123; second, receiving the server's timestamp and Stratum 2 payload; third, computing time drift and transit delay; fourth, adjusting the local clock and incrementing stratum to 3; and fifth, marking the verified peer as synchronized () in system output.
Step-by-Step Solution
Key Concept
NTP Client-Server Synchronization Sequence and Stratum Hierarchy Propagation