Non-GPS derived timing sources (was Re: NTp sources that work in a datacenter)

Sean Donelan sean at
Sun Jun 1 12:18:45 UTC 2003

On Sat, 31 May 2003, Peter Lothberg wrote:
> Time2.Stupi.SE and Time4.Stupi.SE are both stratum-1 accessable through
> the Internet, tracable to UTC-SP (part of TAI) without use of GPS or slaving
> to CDMA (that slaves to GPS).

I was wondering about everyone using GPS-derived timing sources last week.
I looked at 23 different American backbone providers and I think 19 were
traceable back to a GPS clock.  3 were traceable back to USNO/NIST NTP
servers on the Internet synched to their respective master clocks.  And
one claimed to be using the ACTS dialup time service.

I don't expect GPS to spin out of control soon, but I did wonder how
hard it is to find a another reliable clock source of similar quality to
GPS to double check GPS.  US clocks account for 40% of the input to TAI.

More information about the NANOG mailing list