Re: [art] New Version Notification for draft-touch-time-05.txt
Steve Allen <sla@ucolick.org> Tue, 12 November 2019 07:47 UTC
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Date: Mon, 11 Nov 2019 23:47:16 -0800
From: Steve Allen <sla@ucolick.org>
To: Joe Touch <touch@strayalpha.com>
Cc: "art@ietf.org" <art@ietf.org>
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Subject: Re: [art] New Version Notification for draft-touch-time-05.txt
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On Mon 2019-11-11T18:57:53-0800 Joe Touch hath writ: > A little more about PTP, found here: > https://www.iol.unh.edu/sites/default/files/knowledgebase/1588/ptp_overview.pdf > The source above claims PTP tries to coordinate the local clock to TAI. > > That doc confirms it isn’t a time scale, as I originally indicated. In many cases it does not really matter whether a particular instance of PTP is trying to match TAI or any other atomic time scale. The issues of Bulletin Horaire show that the value of TAI is based on re-setting all atomic time scales so that they all had UT2(BIH) - A3 = -1.4123 s at the epoch 1961-01-01T20:00:00 UT2. https://www.ucolick.org/~sla/leapsecs/taiepoch.html The offsets of GPS and other satellite systems are also arbitrary, so the value of any atomic time scale is unrelated to any observable phenomenon. What matters is that the time scale used by a PTP implementation is uniform within the scope of its systems. -- Steve Allen <sla@ucolick.org> WGS-84 (GPS) UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 https://www.ucolick.org/~sla/ Hgt +250 m
- [art] Fwd: New Version Notification for draft-tou… Joe Touch
- Re: [art] New Version Notification for draft-touc… Joe Touch
- Re: [art] Fwd: New Version Notification for draft… Tony Finch
- Re: [art] Fwd: New Version Notification for draft… Joe Touch
- Re: [art] Fwd: New Version Notification for draft… Joe Touch
- Re: [art] Fwd: New Version Notification for draft… Tony Finch
- Re: [art] Fwd: New Version Notification for draft… Joe Touch
- Re: [art] New Version Notification for draft-touc… Joe Touch
- Re: [art] New Version Notification for draft-touc… Steve Allen
- Re: [art] New Version Notification for draft-touc… Tony Finch
- Re: [art] Fwd: New Version Notification for draft… Tony Finch
- Re: [art] New Version Notification for draft-touc… Joe Touch
- Re: [art] New Version Notification for draft-touc… Joe Touch