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Re: [gpsd-dev] [PATCH] Clarifications needed for the time-service HOWTO
From: |
Beat Bolli |
Subject: |
Re: [gpsd-dev] [PATCH] Clarifications needed for the time-service HOWTO |
Date: |
Mon, 21 Oct 2013 22:13:18 +0200 |
User-agent: |
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:24.0) Gecko/20100101 Thunderbird/24.0.1 |
On 21.10.13 19:34, Eric S. Raymond wrote:
> Other experts, feel free to chime in.
>
> Gary E. Miller <address@hidden>:
>>> Is it really true that most public NTP servers are Stratum 2, or
>>> are there more layers in normal use?
>>
>> Maybe most, but you'll see a lof of 1 and 3's.
>
> I've been doing research. Revised text near the end of first section:
>
> You will hear time service people speak of "Stratum 0" (the reference
> clocks) "Stratum 1" (NTP servers directly connected to reference
> clocks over a path with known and compensated-for latency)
> "Stratum 2" (publicly accessible servers that get time from Stratum 1
> over a network link.) Stratum 3 chimers redistribute time from Stratum
> 2, and so forth. There are defined higher strata up to 15, but
> you will probably never see a public chimer higher than Stratum 3.
>
> Ordinary client computers are normally configured to get time from one
> or more Stratum 2 (or less commonly Stratum 3) servers. With GPSD and
> a suitable GPS, you can easily condition your clock to higher
> accuracy than typical Stratum 2; with a little effort you can do
> better than public Stratum 1 servers.
>
> If this is misstating the facts in any way - for example, if Stratum 3
> and up servers are more common than we are implying here - someone
> please speak up.
>
>>> More generally: what can I discover about the quality of the chimers
>>> I listen to?
>>
>> Just compare several.
>
> "Just compare several". How delightfully vague! What I need to
> document for the HOWTO is *how to do this*. Concrete procedure.
>
> (1) What reporting tool do I run?
>
> (2) Where among the numbers it will display for each chimer is
> the figure of merit I should be paying attention to?
>
> (3) What do reasonable values of that figure look like? What
> do weird outliers look like?
>
> It would be illuminating if you replied with a transcript of how
> the report looks on your system and pointed out which numbers are
> the significant ones. If you can include a contrasting report
> from a system with bad chimers, please do.
Let me try this one (see the attachment).
Regards,
Beat
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tuning.diff
Description: Text document
signature.asc
Description: OpenPGP digital signature
- Re: [gpsd-dev] Clarifications needed for the time-service HOWTO, (continued)
Re: [gpsd-dev] Clarifications needed for the time-service HOWTO, Eric S. Raymond, 2013/10/21
Re: [gpsd-dev] Clarifications needed for the time-service HOWTO, Hal Murray, 2013/10/21
Re: [gpsd-dev] Clarifications needed for the time-service HOWTO, Sanjeev Gupta, 2013/10/22
Re: [gpsd-dev] Clarifications needed for the time-service HOWTO, Harlan Stenn, 2013/10/22
Re: [gpsd-dev] [PATCH] Clarifications needed for the time-service HOWTO,
Beat Bolli <=
Re: [gpsd-dev] [PATCH] Clarifications needed for the time-service HOWTO, Gary E. Miller, 2013/10/21
Re: [gpsd-dev] [PATCH] Clarifications needed for the time-service HOWTO, Eric S. Raymond, 2013/10/22
Re: [gpsd-dev] Clarifications needed for the time-service HOWTO, Greg Troxel, 2013/10/21
Re: [gpsd-dev] Clarifications needed for the time-service HOWTO, Andy Walls, 2013/10/21
Re: [gpsd-dev] Clarifications needed for the time-service HOWTO, Hal Murray, 2013/10/22
Re: [gpsd-dev] Clarifications needed for the time-service HOWTO, Eric S. Raymond, 2013/10/22
Re: [gpsd-dev] Clarifications needed for the time-service HOWTO, Andy Walls, 2013/10/22
[gpsd-dev] Direct GPS support in ntpd makes me nervous, Eric S. Raymond, 2013/10/22
Re: [gpsd-dev] Direct GPS support in ntpd makes me nervous, Gary E. Miller, 2013/10/22
Re: [gpsd-dev] Direct GPS support in ntpd makes me nervous, tz, 2013/10/22