Re: [Ntp] Antw: [EXT] [Errata Verified] RFC5905 (5020)

Hi Erik,

The errata has been set to Reported, so you should be able to access to it again.  Let me know if you run into any issues.

Thanks,
Sandy 

> On Jul 28, 2022, at 10:35 AM, Erik Kline <ek.ietf@gmail.com> wrote:
> 
> Ah, yes, I think was not paying sufficient attention to the sign of various expressions.
> 
> I can ask for the erratum to be reopened so that I can revise that.  May I copy from your explanation here to prepare the rejection explanation?
> 
> On Thu, Jul 28, 2022 at 10:19 AM Steven Sommars <stevesommarsntp@gmail.com> wrote:
> I don't get it.
> 
> Theta is "the offset of B relative to A".   The proposed revision is
>    1/2 * [(T2-T1) + (T4-T3)] 
> Example: Let's assume that B and A are exactly synced to UTC and that the network delay is 50msec in each direction.
>     T2-T1 is the NTP mode 3 request delay (including network delay).    This gives 50 msec
>     T4-T3 is the NTP mode 4 response delay (including network delay).   This gives 50 msec.
> The proposed revision gives 100msec/2 = RTT/2, not the expected offset of zero.
> 
> The RFC5905 formula seems correct.
>     theta = T(B) - T(A) = 1/2 * [(T2-T1) + (T3-T4)]
> but might have been clearer had it been written:
>     theta = T(B) - T(A) = 1/2 * [(T2-T1) - (T4-T3)]
> 
> 
> On Thu, Jul 28, 2022 at 4:54 AM Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de> wrote:
> >>> RFC Errata System <rfc-editor@rfc-editor.org> schrieb am 27.07.2022 um
> 17:06 in
> Nachricht <20220727150611.170A66AB09@rfcpa.amsl.com>:
> > The following errata report has been verified for RFC5905,
> > "Network Time Protocol Version 4: Protocol and Algorithms Specification". 
> > 
> > --------------------------------------
> > You may review the report below and at:
> > https://www.rfc-editor.org/errata/eid5020 
> > 
> > --------------------------------------
> > Status: Verified
> > Type: Technical
> > 
> > Reported by: Ferenc Wágner <wferi@niif.hu>
> > Date Reported: 2017-05-15
> > Verified by: Erik Kline (IESG)
> > 
> > Section: 8
> > 
> > Original Text
> > -------------
> > theta = T(B) - T(A) = 1/2 * [(T2-T1) + (T3-T4)]
> > 
> > Corrected Text
> > --------------
> > theta = T(B) - T(A) = 1/2 * [(T2-T1) + (T4-T3)]
> 
> If that's wrong, RFC 1305 would be just as wrong, because it says (page 25 in
> PDF):
> ((Ti−2 − Ti−3) + (Ti−1 − Ti)) / 2
> ,
> 
> > 
> > Notes
> > -----
> > The corresponding code line in A.5.1.1. agrees with this correction:
> > 
> > offset = (LFP2D(r->rec - r->org) + LFP2D(r->dst - r->xmt)) / 2;
> > 
> > taking Figure 7 into account:
> > 
> > | org       | T1         | origin timestamp      |
> > | rec       | T2         | receive timestamp     |
> > | xmt       | T3         | transmit timestamp    |
> > | dst       | T4         | destination timestamp |
> > 
> > --------------------------------------
> > RFC5905 (draft-ietf-ntp-ntpv4-proto-13)
> > --------------------------------------
> > Title               : Network Time Protocol Version 4: Protocol and 
> > Algorithms Specification
> > Publication Date    : June 2010
> > Author(s)           : D. Mills, J. Martin, Ed., J. Burbank, W. Kasch
> > Category            : PROPOSED STANDARD
> > Source              : Network Time Protocols
> > Area                : Internet
> > Stream              : IETF
> > Verifying Party     : IESG
> > 
> > _______________________________________________
> > ntp mailing list
> > ntp@ietf.org 
> > https://www.ietf.org/mailman/listinfo/ntp 
> 
> 
> 
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