nanog mailing list archives
Re: Recommendation on NTP appliances/devices
From: Will Orton <will () loopfree net>
Date: Thu, 3 Apr 2014 21:25:27 -0700
On Thu, Apr 03, 2014 at 09:06:57PM -0700, George Herbert wrote:
Sadly, right now that either means your own real clock, or WWV. The cellphone time is (as far as I know, for the networks I saw data on) all coming off GPS. Fortunately real clocks are coming way down in cost.
There are commercially available NTP servers with GPS + Rb oscillators... for NTP use you could basically let it sync up a couple days, disconnect the GPS and let it freerun. You'd still be within a millisecond of GPS even after a couple years most likely. Reconnect it to GPS for a couple days every 1-2 years to resync it. More fun and cheaper to build your own I'd bet, if you had the time. With clocks/oscillators designed to provide hold-over for synchronous networks and microwave RF systems (parts per million or billion) the demands of NTP for general use in an IP network are pretty modest. You lose more accuracy in NTP stratum 1->2 across a (relaively) jittery WAN link than a cheap atomic clock does in a long time. -Will
Current thread:
- Recommendation on NTP appliances/devices David Hubbard (Apr 03)
- Re: Recommendation on NTP appliances/devices Majdi S. Abbas (Apr 03)
- Re: Recommendation on NTP appliances/devices Julien Goodwin (Apr 04)
- Re: Recommendation on NTP appliances/devices William F. Maton Sotomayor (Apr 04)
- <Possible follow-ups>
- Re: Recommendation on NTP appliances/devices Berry Mobley (Apr 03)
- Re: Recommendation on NTP appliances/devices Rob Seastrom (Apr 03)
- Re: Recommendation on NTP appliances/devices Chris Adams (Apr 03)
- Re: Recommendation on NTP appliances/devices Rob Seastrom (Apr 03)
- Re: Recommendation on NTP appliances/devices George Herbert (Apr 03)
- Re: Recommendation on NTP appliances/devices Will Orton (Apr 03)
- Re: Recommendation on NTP appliances/devices Saku Ytti (Apr 03)
- Re: Recommendation on NTP appliances/devices Julien Goodwin (Apr 04)
- Re: Recommendation on NTP appliances/devices Saku Ytti (Apr 04)
- Re: Recommendation on NTP appliances/devices Julien Goodwin (Apr 04)
- Re: Recommendation on NTP appliances/devices Saku Ytti (Apr 04)
- Re: Recommendation on NTP appliances/devices Dan Drown (Apr 04)
- Re: Recommendation on NTP appliances/devices Rob Seastrom (Apr 03)
- Re: Recommendation on NTP appliances/devices Majdi S. Abbas (Apr 03)
- Re: Recommendation on NTP appliances/devices bmanning (Apr 03)