[Ntp] Antw: [EXT] Re: I-D Action: draft-ietf-ntp-chronos-01.txt

[Ulrich Windl <[e-mail]>]

Hi!

A few random comments (on the HTML version):

Table 1: The "Meaning" column should not be centered. The descriptions for "Err" and "K" are very short (compared to the rest).

On "3": Instead of referring just to "Sections 10 and 11" the title of the sections could at least be mentioned. I guess nobody known by heart what these sections are about without openeing the RFC first...

On "3.1" Maybe explain what the outcome is, compared to that happening in NTP usually. More trustworthy error estimate? What can affect the result in a negative way?

On "3.2": "the third lowest-value samples": It reads like one sample (the thrid-lowest) is removed; did you mean you remove the lowest third of the samples? You use "2w" without explaining how w is determined.

All together section 3 is very abstact, and maybe could use some example numbers for illustration.

Section 4: Waht's the value of "K"? On "S": How is a sample oth tens servers stored in a single variable? Likewise "T".

It seems S and T are arrays. Maybe add a data type for variables, even for pseudo-code.


In summary, the draft reads very much like an "idea" (like the typical American patent request), but not at all like a specification.

Regards,
Ulrich Windl

>>> Neta R S <[e-mail]> schrieb am 03.09.2020 um 10:11 in Nachricht
<CAM-HxCMfF-+Ug9qzEfwfYvDys0CEE3=i7JQk=[e-mail]>:
> Dear all,
> 
> We updated Chronos' draft in order to avoid expiration.
> This version was presented in the last working group meeting about a
> month ago, as it is similar to version 00.
> 
> The current approach considers Chronos as a watchdog, which
> periodically monitors the NTP clock and only when a suspected attack
> is detected does the Chronos algorithm take over, replacing the NTP
> selection and combining algorithms.
> 
> We believe this approach resolves the concerns that were raised about
> the potentially low precision of previous versions of Chronos.
> 
> We would highly appreciate feedback about the current version of Chronos,
> and we invite members to join us and assist with the implementation.
> 
> Best regards,
> On behalf of the Chronos authors.
> 
> On Thu, Sep 3, 2020 at 10:46 AM <[e-mail]> 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 WG of the IETF.
>>
>>         Title           : A Secure Selection and Filtering Mechanism for
>> the Network Time Protocol Version 4
>>         Authors         : Neta Rozen-Schiff
>>                           Danny Dolev
>>                           Tal Mizrahi
>>                           Michael Schapira
>>         Filename        : draft-ietf-ntp-chronos-01.txt
>>         Pages           : 11
>>         Date            : 2020-09-03
>>
>> Abstract:
>>    The Network Time Protocol version 4 (NTPv4), as defined in RFC 5905,
>>    is the mechanism used by NTP clients to synchronize with NTP servers
>>    across the Internet.  This document specifies an extension to the
>>    NTPv4 client, named Chronos, which is used as a "watchdog" alongside
>>    NTPv4, and provides improved security against time shifting attacks.
>>    Chronos involves changes to the NTP client's system process only and
>>    is backwards compatible with NTPv4 servers.
>>
>>
>> The IETF datatracker status page for this draft is:
>> https://datatracker.ietf.org/doc/draft-ietf-ntp-chronos/ 
>>
>> There are also htmlized versions available at:
>> https://tools.ietf.org/html/draft-ietf-ntp-chronos-01 
>> https://datatracker.ietf.org/doc/html/draft-ietf-ntp-chronos-01 
>>
>> A diff from the previous version is available at:
>> https://www.ietf.org/rfcdiff?url2=draft-ietf-ntp-chronos-01 
>>
>>
>> Please note that it may take a couple of minutes from the time of
>> submission
>> until the htmlized version and diff are available at tools.ietf.org.
>>
>> Internet-Drafts are also available by anonymous FTP at:
>> ftp://ftp.ietf.org/internet-drafts/ 
>>
>>
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