[Ntp] [Errata Verified] RFC5905 (5600)

RFC Errata System <rfc-editor@rfc-editor.org> Mon, 29 August 2022 23:27 UTC

To: takashi.nakamoto@nao.ac.jp, mills@udel.edu, jrmii@isc.org, jack.burbank@jhuapl.edu, william.kasch@jhuapl.edu
From: RFC Errata System <rfc-editor@rfc-editor.org>
Cc: ek.ietf@gmail.com, iesg@ietf.org, ntp@ietf.org, iana@iana.org, rfc-editor@rfc-editor.org
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Message-Id: <20220829232605.5EB6C55D49@rfcpa.amsl.com>
Date: Mon, 29 Aug 2022 16:26:05 -0700
Archived-At: <https://mailarchive.ietf.org/arch/msg/ntp/WMACav-O4e_ByFbcFZpt0y9XceM>
Subject: [Ntp] [Errata Verified] RFC5905 (5600)
Precedence: list

The following errata report has been verified for RFC5905,
"Network Time Protocol Version 4: Protocol and Algorithms Specification". 

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You may review the report below and at:
https://www.rfc-editor.org/errata/eid5600

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Status: Verified
Type: Technical

Reported by: Takashi Nakamoto <takashi.nakamoto@nao.ac.jp>
Date Reported: 2019-01-15
Verified by: Erik Kline (IESG)

Section: 10.

Original Text
-------------
   Let the first stage offset in the sorted list be theta_0; then, for
   the other stages in any order, the jitter is the RMS average

                          +-----                 -----+^1/2
                          |  n-1                      |
                          |  ---                      |
                  1       |  \                     2  |
      psi   =  -------- * |  /    (theta_0-theta_j)   |
                (n-1)     |  ---                      |
                          |  j=1                      |
                          +-----                 -----+

Corrected Text
--------------
   Let the first stage offset in the sorted list be theta_0; then, for
   the other stages in any order, the jitter is the RMS average

               +-----                             -----+^1/2
               |              n-1                      |
               |              ---                      |
               |    1         \                     2  |
      psi   =  | -------- *   /    (theta_0-theta_j)   |
               |  (n-1)       ---                      |
               |              j=1                      |
               +-----                             -----+

Notes
-----
The formula to calculate jitter "psi" in section "10.  Clock Filter Algorithm" is incorrect, and also inconsistent with the formulate to calculate "psi_s" in section "11.2.2.  Cluster Algorithm".

"psi" is defined as RMS average, so the term 1/(n-1) should be within [ ]^1/2 block.

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RFC5905 (draft-ietf-ntp-ntpv4-proto-13)
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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] [Errata Verified] RFC5905 (5600) RFC Errata System