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

"Ulrich Windl" <Ulrich.Windl@rz.uni-regensburg.de> Mon, 02 September 2019 06:36 UTC

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Date: Mon, 02 Sep 2019 08:35:58 +0200
From: "Ulrich Windl" <Ulrich.Windl@rz.uni-regensburg.de>
To: "ntp@ietf.org" <ntp@ietf.org>,<magnus@rubidium.se>
References: <1B4A56E7-16A6-4767-9268-BCF4BEB9A247@isoc.org> <BCA949D7-7D92-43A9-9766-573559A9FC70@meinberg.de> <5D66392D020000A100033273@gwsmtp.uni-regensburg.de> <8F6BAF5F-CC7B-47B9-90FD-BD20D6ABE845@meinberg.de> <20190828103752.GI24761@localhost> <3f4b55ca-02d9-a470-229b-40860866efbf@nwtime.org> <20190828111458.GJ24761@localhost> <e50112dd-f918-1135-74c8-a738ecb70b70@nwtime.org> <55867E75-9813-466B-8E57-0E157DE5AEB9@meinberg.de> <d308b5d4-3d6e-981b-3dfc-9d5938bad78d@rubidium.se>
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Subject: [Ntp] Antw: Re: Antw: Re: Calls for Adoption -- NTP Extension Field drafts -- Four separate drafts
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>>> Magnus Danielson <magnus@rubidium.se> schrieb am 28.08.2019 um 13:30 in
Nachricht <d308b5d4-3d6e-981b-3dfc-9d5938bad78d@rubidium.se>se>:
> I agree. If someone knocks on the door with v5 packets, reply in v5
> form, if someone knocks on the door with v4 packets, reply in v4 form.
> As people migrate to v5, they can start using all the benefits from it.
> For loop‑protection, keeping a list of nodes from the source is a very
> easy base condition to avoid routing loops, since as an announcement

But remember that a "note" is NOT "an IP address". With multi-homed hosts you
can have interesting synchronization loops... ;-)

> comes in, if none of the nodes in the list is oneself, you may use it,
> where as if any of the nodes is oneself, a loop is for sure detected.
> While the trace loop detection mechanism is sufficient in theory, it
> does not completely solve all loop problems, as transient loops may
> occur, but it at least avoids problems in the long term.
> If I only had time to describe all the things I would do to enhance NTP,
> it has a number of built‑in assumptions which is not useful or correct.
> Cheers,
> Magnus
> On 2019‑08‑28 13:23, Heiko Gerstung wrote:
>> Why not define a method in v5 that not only protects against degree 1 loops

> but maybe also against degree 2,3 or n? 
>> This is what I meant when trying to explain that we should not stick to the

> existing packet format with its shortcomings.
>> Regards,
>>    Heiko
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