A network administrator configures a Cisco IOS router to synchronize its internal clock with an enterprise NTP server operating at Stratum 2. Arrange the operational steps in chronological order from initial packet transmission to the point where the router can act as a valid time source for downstream clients.
- 1The router sends an NTP client mode query (UDP port 123) to the configured Stratum 2 server IP address.
- 2The router receives an NTP server mode response containing time payload data, reference ID, and Stratum 2 metadata.
- 3The router computes round-trip delay, dispersion, and clock offset algorithms to validate time accuracy.
- 4The router synchronizes its system clock and increments its own operational stratum level to Stratum 3.
- 5The router begins answering incoming NTP queries from downstream clients using its newly established Stratum 3 reference.
Answer
The correct sequence of operations is: 1) The router sends an NTP client mode query (UDP port 123) to the server. 2) The router receives an NTP server mode response with Stratum 2 metadata. 3) The router computes round-trip delay, dispersion, and clock offset algorithms. 4) The router synchronizes its system clock and increments its operational stratum to Stratum 3. 5) The router begins answering incoming NTP queries from downstream clients.
NTP synchronization follows a strict sequential process: outbound UDP 123 request initiation, receipt of server time payload and stratum attributes, statistical filtering of offset and round-trip delay, local clock adjustment accompanied by stratum incrementing (), and finally responding to downstream client requests as a synchronized master time source.
Step-by-Step Solution
Key Concept
NTP Client-Server Initialization Sequence and Stratum Calculation