Subject: [ntpwg] I-D ACTION:draft-ietf-ntp-ntpv4-proto-05.txt

From: brian at innovationslab.net (Brian Haberman)
Date: Mon, 14 May 2007 10:12:08 -0400

All,
     This version of the protocol specification incorporates all
comments received to date (to my knowledge).  Please review.  My plan is
to start a working group last call on this document in the next week or so.

Regards,
Brian

Internet-Drafts at ietf.org wrote:
> A New Internet-Draft is available from the on-line Internet-Drafts 
> directories.
> This draft is a work item of the Network Time Protocol Working Group of the IETF.
> 
> 	Title		: Network Time Protocol Version 4 Protocol And Algorithms Specification
> 	Author(s)	: J. Burbank, et al.
> 	Filename	: draft-ietf-ntp-ntpv4-proto-05.txt
> 	Pages		: 108
> 	Date		: 2007-5-11
> 	
> The Network Time Protocol (NTP) is widely used to synchronize
>    computer clocks in the Internet.  This document describes NTP Version
>    4 (NTPv4), which is backwards compatible with NTP Version 3 (NTPv3)
>    described in RFC 1305, as well as previous versions of the protocol.
> 
>    It includes a modified protocol header to accommodate the Internet
>    Protocol Version 6 address family.  NTPv4 includes fundamental
>    improvements in the mitigation and discipline algorithms which extend
>    the potential accuracy to the tens of microseconds with modern
>    workstations and fast LANs.  It includes a dynamic server discovery
>    scheme, so that in many cases specific server configuration is not
>    required.  It corrects certain errors in the NTPv3 design and
>    implementation and includes an optional extension mechanism.
> 
> A URL for this Internet-Draft is:
> http://www.ietf.org/internet-drafts/draft-ietf-ntp-ntpv4-proto-05.txt

---

From: mills at udel.edu (David L. Mills)
Date: Tue, 15 May 2007 01:15:30 +0000

Brian,

Correct the equation and minor text on page 9: This is through Section 
6. More to follow.

A timestamp T(t) represents either the UTC date or time offset from
   UTC at running time t.  Which meaning is intended should be clear
   from the context.  Let T(t) be the time offset, R(t) the frequency
   offset, D(t) the ageing rate (first derivative of R(t) with respect
   to t).  Then, if T(t_0) is the UTC time offset determined at t = t_0,
   the UTC time offset at time t is

   T(t) = T(t_0) + R(t_0)(t-t_0) + 1/2 * D(t_0)(t-t_0)^2 + e,

   where e is a stochastic error term discussed later in this document.

Brian Haberman wrote:

> _______________________________________________
> ntpwg mailing list
> ntpwg at lists.ntp.isc.org
> https://lists.ntp.isc.org/mailman/listinfo/ntpwg

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From: mills at udel.edu (David L. Mills)
Date: Wed, 23 May 2007 01:30:49 +0000

Brian,

Further checking the latest draft reveals the appendix is all messed up. 
Some tabs (spaces) are mutiliated and some pages are truncated. I spent 
a lot of time reformatting the original version and verified Harlan's 
initial draft preserved the formatting. This may be the same thing that 
happend in the original draft and I later painstakingly repaired.

Further reports may be expected.

Dave

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From: mills at udel.edu (David L. Mills)
Date: Wed, 23 May 2007 02:21:15 +0000

Brian,

Hold the train; I picked up the wrong version. Version -05 appendix is 
okay. Sorry about that.

Dave

David L. Mills wrote:

> Brian,
>
> Further checking the latest draft reveals the appendix is all messed 
> up. Some tabs (spaces) are mutiliated and some pages are truncated. I 
> spent a lot of time reformatting the original version and verified 
> Harlan's initial draft preserved the formatting. This may be the same 
> thing that happend in the original draft and I later painstakingly 
> repaired.
>
> ------------------------------------------------------------------------
>

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From: mills at udel.edu (David L. Mills)
Date: Thu, 24 May 2007 02:20:48 +0000

Brian,

Other than a brief discussion and correction of a couple formulas, I 
have seen no substantive contributions/corrections or even typos in the 
document. However, after a careful review there are several nitpicks and 
some broken things yet in the document.

Page 10. The equation for T(t) is wrong as previously noted.

Page 25. The last extension field is padded to a 64-bit boundary is 
false. All fields, including the last, are padded to a 32-bit boundary.

Page 29. The equation for theta is wrong as previously noted.

Page 31. A note has been added with respect to a recently found protocol 
vulnerabily. While replays of the server message are caught and 
suppressed, replays of the original client message, which cuases a 
spurious server message, are not. The note suggests a solution.

Page 33. A spurious sentence was inserted in the graf beginning "The 
variables defined in Figure 19..."

Page 39 and 45. The equations for jitter have gross errors.

Page 40. Graf beginning "It is important to note..." contains an awkward 
and misleading sentence.

Page 41, Figure 27. The system variable v is missing.

Page 47, first graf. Sentence added to set the clock if the step 
threshold is exceeded.

There are several other minor typos in the text that should not affect 
the formatting. As of tomorrow (23 May, the NTP project page will have 
(a) the -05 document, (b) the marked up (-06?) document and a context 
diff which shows all changes.

Another issue so far unresolved is what to do about the control and 
monitoring protocol, which has not changed from NTPv3. The simplest 
solution would be to incorporate the NTPv3 appendix by reference. 
However, this makes it hard to deprecate RFC 1305 completely. The RFC 
Editor may require the appendix be incorporated in the document or be 
the topic of a new RFC.

Dave

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