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-   -   Help understanding NTP behaviour (http://www.linux-archive.org/debian-isp/672215-help-understanding-ntp-behaviour.html)

Ross Halliday 05-29-2012 01:28 PM

Help understanding NTP behaviour
 
> An offset of almost 1 second suggests that the GPS receivers are using
> a pulse-per-second for high accuracy, but are have synched their
> ticking to the wrong second. In other words, they know when each
> second of UTC ticks, just their clock is one second out to start with.

Thanks, it makes sense that these devices would be so slow (sounds plausible to me, anyway) as they weren't supposed to be clocks originally. Even so, why would my server keep changing the offset? Should it not remain constant?

---
Ross Halliday
Network Operations
WTC Communications

Office: 613-547-6939 x203
Helpdesk: 866-547-6939 option 2
http://www.wtccommunications.ca


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Ross Halliday 05-29-2012 01:52 PM

Help understanding NTP behaviour
 
> I don't think that this is a Debian-specific issue. In my experience
> WiFi latency is simply too unstable for timing. Plus these router/CPE
> devices are reputed to be less than suitable for use as time servers.

Indeed WiFi is - and almost none of these backhauls are 802.11-based. The majority of these links are Motorola/Orthogon and Redline OFDM gear suitable for transporting TDM voice with a bit of Dragonwave thrown in for fun :) I'm not sure where the router/CPE comment comes from as these are devices installed on towers for providing GPS timing pulse to access points, but I do agree.

> You may also want to ask your question on the comp.protocols.time.ntp
> Usenet news-group or the gatewayed questions@lists.ntp.org mailing
> list.
> These fora will get you in contact with the NTP developers and core
> user
> community.
>
> Please note that you will need to visit
> http://lists.ntp.org/listinfo/questions and subscribe prior to posting
> to the mailing list.
>
> Fair warning: The NTP developers are rather FreeBSD-centric and don't
> care
> about package manager integrity; the usual knee-jerk advice is to tell
> you to upgrade to the current ntp-developement release from their
> source
> distribution.

Thanks! Appreciate the heads up :) I will ask the folks over there.

Cheers
---
Ross Halliday
Network Operations
WTC Communications

Office: 613-547-6939 x203
Helpdesk: 866-547-6939 option 2
http://www.wtccommunications.ca


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