[Ntp] Antw: Re: Antw: Re: Calls for Adoption -- NTP Extension Field drafts -- Four separate drafts
"Ulrich Windl" <Ulrich.Windl@rz.uni-regensburg.de> Wed, 28 August 2019 12:25 UTC
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Date: Wed, 28 Aug 2019 14:25:49 +0200
From: Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>
To: "ntp@ietf.org" <ntp@ietf.org>, Heiko Gerstung <heiko.gerstung@meinberg.de>, stenn@nwtime.org
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> <1c374597-c431-9149-f655-d69d9b21b187@nwtime.org> <E58275AC-9EC8-46D7-B160-7F8F3EF1C817@meinberg.de>
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Subject: [Ntp] Antw: Re: Antw: Re: Calls for Adoption -- NTP Extension Field drafts -- Four separate drafts
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>>> Heiko Gerstung <heiko.gerstung@meinberg.de> schrieb am 28.08.2019 um 13:59 in Nachricht <E58275AC-9EC8-46D7-B160-7F8F3EF1C817@meinberg.de>: > Harlan, > > I asked why we would not want to improve the loop prevention mechanism, I do > not have a solution at hand which I sketched out in full detail already. But > here is a possibility that came to my mind just now, it certainly needs to be > refined and checked and modified: > > - create a random ID on each server at startup I'd add a "double-may" there: The ID MAY be random, and it MAY be re-created on each server startup. Maybe think of it like the driftfile that preserves some value across restarts. > - communicate that ID to each client which indicates (e.g. by an EF) that it > is interested in this information, for example if it wants to be a server > itself (stratum 2+) Why not always add it? > - a tier-2 server uses that ID from its upstream server as its refID > - any server that is interested in degree n - loop detection will indicate > this (using an EF, maybe something like the I-DO EF) to its upstream > server(s) > - those servers respond with an EF containing a list of IDs representing the > sync chain, maybe limited to n entries (if the requesting client asks for > only n entries) > - now, if this server which received the chain of IDs from its upstream > server(s) now is questioned by one of its downstream clients about the chain > of sync, it will add the RefID of its upstream servers to the sync chain > received by that upstream server and push this down to the client > > This way, those clients interested in only degree 1 loop protection just use > the RefID field. And those who are interested in degree n loop protection can > request the chain of IDs from their upstream servers. > > The freedom to change the packet header format would allow us to increase > the number of bytes for the RefID to improve security (more bytes, harder to > guess). > > We have had cases where a server A was synchronized by server B which was > synchronized by server C. Server C also used Server D which was synchronized > by Server A, i.e. whenever your client believes it has more than one source > of time and it turns out that all of them go back to one single source. > Adding non-randomized IDs like "GPS" to the sync chain (by the stratum 1 > server) would also allow the clients to identify if they are relying on one > single source of time, which in turn would make it possible to choose another > server with a different source (like Galileo) instead. So this applies only to stratum-1 servers (which had spacial refIDs anyway). What about having a "normal" REFID for stratum 1 servers, and adding a mandatory "reference source class" (like "GPS", "Gallileo" (note the extra length!), "NTP" (for stratum > 1), "DCF-77", etc? (Or even do it the GPT-way: Allocate UUIDs (well, GUIDs will do as well) for all known reference clock sources?) And if you like splitting hairs, you could have different IDs for the "time source" (like TAI), the "time carrier" (like GPS) and the "time access point" (effectively the interface providing GPS time) like "Product X from Vendor Y with further details Z"... So if a specific product has a bug, you could filter it; if a specific carrier has a problem, you could filter it, and if you distrust some source, you could filter it... ;-) Regards, Ulrich > > Best Regards, > Heiko > > > -- > Heiko Gerstung > Managing Director > > MEINBERG® Funkuhren GmbH & Co. KG > Lange Wand 9 > D-31812 Bad Pyrmont, Germany > Phone: +49 (0)5281 9309-404 > Fax: +49 (0)5281 9309-9404 > > Amtsgericht Hannover 17HRA 100322 > Geschäftsführer/Management: Günter Meinberg, Werner Meinberg, Andre > Hartmann, Heiko Gerstung > > Email: > heiko.gerstung@meinberg.de > Web: > Deutsch https://www.meinberg.de > English https://www.meinbergglobal.com > > Do not miss our Time Synchronization Blog: > https://blog.meinbergglobal.com > > Connect via LinkedIn: > https://www.linkedin.com/in/heikogerstung > > > > On 28.08.19, 13:38 "ntp im Auftrag von Harlan Stenn" <ntp-bounces@ietf.org > im Auftrag von stenn@nwtime.org> wrote: > > > > On 8/28/2019 4:23 AM, 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. > > Exactly how would this work? > > Has there been any reported instances of this being useful or needed for > NTP? > > What abuse vectors would this create? > > > Regards, > > Heiko > > > > -- > Harlan Stenn, Network Time Foundation > http://nwtime.org - be a Member! > > _______________________________________________ > ntp mailing list > ntp@ietf.org > https://www.ietf.org/mailman/listinfo/ntp > > > > _______________________________________________ > ntp mailing list > ntp@ietf.org > https://www.ietf.org/mailman/listinfo/ntp
- [Ntp] Calls for Adoption -- NTP Extension Field d… Karen O'Donoghue
- Re: [Ntp] Calls for Adoption -- NTP Extension Fie… Heiko Gerstung
- [Ntp] Antw: Re: Calls for Adoption -- NTP Extensi… Ulrich Windl
- Re: [Ntp] Calls for Adoption -- NTP Extension Fie… tglassey@earthlink.net
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Heiko Gerstung
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Miroslav Lichvar
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Miroslav Lichvar
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Harlan Stenn
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Heiko Gerstung
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Miroslav Lichvar
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Harlan Stenn
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Heiko Gerstung
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Miroslav Lichvar
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Harlan Stenn
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Harlan Stenn
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Heiko Gerstung
- [Ntp] Antw: Re: Antw: Re: Calls for Adoption -- N… Ulrich Windl
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Miroslav Lichvar
- Re: [Ntp] Calls for Adoption -- NTP Extension Fie… Daniel Franke
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Heiko Gerstung
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Heiko Gerstung
- Re: [Ntp] Calls for Adoption -- NTP Extension Fie… Watson Ladd
- Re: [Ntp] Calls for Adoption -- NTP Extension Fie… Salz, Rich
- [Ntp] Antw: Re: Antw: Re: Calls for Adoption -- N… Ulrich Windl
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Dieter Sibold
- Re: [Ntp] Calls for Adoption -- NTP Extension Fie… kristof.teichel
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Magnus Danielson
- [Ntp] Antw: Re: Antw: Re: Calls for Adoption -- N… Ulrich Windl
- [Ntp] Antw: Antw: Re: Antw: Re: Calls for Adoptio… Ulrich Windl
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Miroslav Lichvar
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Heiko Gerstung
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Hal Murray
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Miroslav Lichvar
- [Ntp] Antw: Re: Antw: Re: Calls for Adoption -- N… Ulrich Windl
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Harlan Stenn
- [Ntp] Antw: Re: Antw: Re: Antw: Re: Calls for Ado… Ulrich Windl
- [Ntp] Antw: Re: Antw: Re: Antw: Re: Calls for Ado… Ulrich Windl
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Heiko Gerstung
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Harlan Stenn
- [Ntp] Antw: Re: Antw: Re: Antw: Re: Calls for Ado… Ulrich Windl
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Heiko Gerstung
- Re: [Ntp] Calls for Adoption -- NTP Extension Fie… Miroslav Lichvar
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Harlan Stenn
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Magnus Danielson
- Re: [Ntp] Antw: Re: Antw: Re: Antw: Re: Calls for… Harlan Stenn
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Heiko Gerstung
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Harlan Stenn
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Harlan Stenn
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Daniel Franke
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Miroslav Lichvar
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Harlan Stenn
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Heiko Gerstung
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Hal Murray
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Heiko Gerstung
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Harlan Stenn
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Harlan Stenn
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Heiko Gerstung
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Hal Murray
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Miroslav Lichvar
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Heiko Gerstung
- [Ntp] Antw: Re: Antw: Re: Antw: Re: Calls for Ado… Ulrich Windl
- [Ntp] Antw: Re: Antw: Re: Antw: Re: Calls for Ado… Ulrich Windl
- Re: [Ntp] Antw: Re: Antw: Re: Antw: Re: Calls for… Watson Ladd
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Salz, Rich
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Daniel Franke
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Salz, Rich
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Daniel Franke
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Salz, Rich
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Salz, Rich
- [Ntp] NTP errors Hal Murray
- Re: [Ntp] Calls for Adoption -- NTP Extension Fie… Harlan Stenn
- [Ntp] Antw: Re: Antw: Re: Calls for Adoption -- N… Ulrich Windl
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Watson Ladd
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Hal Murray
- [Ntp] Antw: Re: Antw: Re: Antw: Re: Calls for Ado… Ulrich Windl
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Miroslav Lichvar
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Hal Murray
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Miroslav Lichvar
- Re: [Ntp] Calls for Adoption -- NTP Extension Fie… Fernando Gont
- Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Ext… Miroslav Lichvar
- [Ntp] Antw: Re: Antw: Re: Calls for Adoption -- N… Ulrich Windl
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Harlan Stenn
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Miroslav Lichvar
- [Ntp] Antw: Re: Antw: Re: Antw: Re: Calls for Ado… Ulrich Windl
- Re: [Ntp] Antw: Re: Antw: Re: Antw: Re: Calls for… Watson Ladd
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Hal Murray
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Mark Atwood
- Re: [Ntp] Antw: Re: Antw: Re: Calls for Adoption … Steven Sommars
- [Ntp] Antw: Re: Antw: Re: Antw: Re: Calls for Ado… Ulrich Windl