CompTIA Network+ (N10-009)Network OperationsHard
A network engineer configures an internal NTP server that receives its time directly from a GPS receiver connected via a serial cable. This internal server then distributes time to all other devices on the corporate network. What stratum level is this internal NTP server?
- AStratum 2
- BStratum 0
- CStratum 1
- DStratum 3
Show answer & explanationAnswer & explanation
Correct answer: C. Stratum 1
Stratum 0 devices are the reference clocks themselves (such as GPS or atomic clocks) and do not communicate on the network. A server directly connected to a stratum 0 source, like this GPS-linked server, is stratum 1. Devices that then sync from this server become stratum 2.
Why the other options are wrong
- A. Stratum 2 would apply to devices syncing their time from this stratum 1 server.
- B. Stratum 0 refers to the GPS reference clock itself, not the server connected to it.
- D. Stratum 3 would be even further removed, syncing from a stratum 2 source.
NTP Stratum Levels
A numbering system describing a device's distance from an authoritative time reference, with lower numbers being closer to the source.
- Stratum 0: reference clocks (GPS, atomic) - not networked
- Stratum 1: servers directly connected to stratum 0 sources
- Each additional hop from the source increases the stratum number by 1
Memory trick: Stratum counts hops from the GPS 'ground zero'.