NTP Stratum Levels and Clock Synchronization: CCIE Security Exam

NTP Stratum Levels

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Which NTP stratum level means that the clock is unsynchronized?



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A. B. C. D.


In the Network Time Protocol (NTP), stratum level is used to indicate the number of hops away from a highly accurate time source. A stratum 1 time server is directly connected to an accurate time source, such as an atomic clock, while a stratum 2 time server receives its time from a stratum 1 server, and so on.

Each NTP server in a hierarchy is assigned a stratum level based on its distance from the reference clock, with the most accurate time source having a stratum level of 0. Stratum levels range from 0 to 15, with 16 being reserved for unsynchronized systems.

So, the answer to the question is D. Stratum level 16 means that the clock is unsynchronized. This can occur if the NTP server is unable to synchronize with any reference clock, or if the NTP server has not yet been able to synchronize its clock since starting up.

It is important to note that NTP servers should always be configured to obtain time from a highly accurate and reliable source, such as a stratum 1 server, to ensure accurate time synchronization throughout the network.