What NTP Stratum level is a server that is connected directly to an authoritative time source?

Question

Exhibit

Options

• AStratum 0
• BStratum 1
• CStratum 14
• DStratum 15

• A
  1% (1)
• B
  94% (66)
• C
  1% (1)
• D
  3% (2)

Explanation

Stratum 1 servers are directly connected to an authoritative time source (such as an atomic clock, GPS receiver, or radio clock), making them the highest level of network time servers in the NTP hierarchy.

Why the distractors are wrong:

• Stratum 0 refers to the authoritative time source itself (e.g., the atomic clock or GPS device) - it is a reference device, not a network time server that other devices sync from.
• Stratum 14 and 15 are near the bottom of the NTP hierarchy (which goes from 0–15); Stratum 15 specifically indicates an unsynchronized server, making these clearly incorrect.

Memory Tip: Think of it this way - Stratum 0 is the source (the clock itself), and Stratum 1 is one step away from that source. Each additional stratum number represents one more hop away from the original time reference. "1st in line from the source = Stratum 1."

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