Re: [Ntp] Calls for Adoption -- NTP Extension Field drafts -- Four separate drafts

kristof.teichel@ptb.de Fri, 30 August 2019 12:33 UTC

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Subject: Re: [Ntp] Calls for Adoption -- NTP Extension Field drafts -- Four separate drafts
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Hello all,

I also oppose adoption of the four draft as documents intended for use 
with NTPv4.

I broadly agree with Heiko's assessment insofar as I think most of the 
individual content in the four drafts is relevant, but should be treated 
in a different context: 
not as an attempt to repair the holes that are opening up in NTPv4, but as 
a set of principles going into the next revision of NTP ("NTPv5", likely).

Best regards,
Kristof


P.S.:

This is especially drastic for the I-DO proposal, where I do not see how 
it makes sense to try to catch implementation that are too old to 
understand certain newer EFs by forcing them to understand another new EF 
with which they can talk about which EFs they do understand.
It does seem important to do something akin to this, but I really think it 
only makes sense if you can assume ALL implementations to a) understand 
the I-DO-inspired EF and b) be able to use crypto methods to provide 
authentication for whatever is in the I-DO-inspired EF.

Semi-related, I really believe NTPv5 should enable behavior that splits 
messages (especially server responses) into two parts, the first as small 
as possible, basically only an identifier saying that it is an NTP packet 
and providing an ID for the association/exchange it belongs to, the second 
carrying all the timestamps and meta information.
This would enable an almost completely free choice of information that a 
client could request, each piece of it in its own extension field, without 
it endangering speed or accuracy.
But it is another feature you can only have if you can expect all 
participants to understand it.





Von:    "Heiko Gerstung" <heiko.gerstung@meinberg.de>
An:     "Karen O'Donoghue" <odonoghue@isoc.org>rg>, "ntp@ietf.org" 
<ntp@ietf.org>
Datum:  28.08.2019 08:55
Betreff:        Re: [Ntp] Calls for Adoption -- NTP Extension Field drafts 
-- Four separate drafts
Gesendet von:   "ntp" <ntp-bounces@ietf.org>



Hi,

I do not support adopting all four drafts, I believe that we should either 
integrate them into a new revision of NTP ("NTPv5") or fix them 
problems/issues they address in that new "NTPv5" RFC. Most of the issues 
addressed by those drafts can be easily solved by changing/expanding the 
NTP packet format for "NTPv5". 

The "REFID" draft would be obsolete if an NTPv5 packet header for a server 
mode packet by definition includes  a "MY_ID" field. 

The "MAC/last extension field" draft would be obsolete if we define that 
NTPv5 does only support Extension Fields as allowed additional data and a 
MAC in v5 is always transported inside an extension field (the "MAC-EF" 
approach as described in the draft, for example). 

The "I-DO extension field" draft would be something I would integrate into 
a "NTPv5" RFC as a mandatory requirement for NTP servers. 

The "Extended Information Extension Field" draft would be obsolete if we 
introduce either additional packet header fields in v5 or just defined a 
new EF for information that we think should be available from the server. 
That EF could be sent or not, based on whether the client wants it or not 
(indicated by an EF sent by that client in its request, for example). 

Best Regards,
   Heiko


-- 
Heiko Gerstung 
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On 28.08.19, 05:38 "ntp im Auftrag von Karen O'Donoghue" 
<ntp-bounces@ietf.org im Auftrag von odonoghue@isoc.org> wrote:

    Folks,
 
    The following four drafts are four different proposals for new 
extension fields. Please review each draft and indicate whether these 
should be adopted by the working group. I am sending them all as one set 
because they are all extension fields, but we need a response for each 
draft listed below. 
 
    Thanks!
    Karen and Dieter
 
    1.  Network Time Protocol Extended Information Extension Field
    https://datatracker.ietf.org/doc/draft-stenn-ntp-extended-information/
 
    2.  Network Time Protocol I-Do Extension Field
    https://datatracker.ietf.org/doc/draft-stenn-ntp-i-do/
 
    3.  Network Time Protocol MAC/Last Extension Fields
    https://datatracker.ietf.org/doc/draft-stenn-ntp-mac-last-ef/
 
    4.  Network Time Protocol Suggested REFID Extension Field
    https://datatracker.ietf.org/doc/draft-stenn-ntp-suggest-refid/
 
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