IETF Logo Mail Archive

Re: [Ntp] [EXT] Re: The bump, or why NTP v5 must specify impulse response

Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de> Tue, 14 April 2020 20:39 UTC

Return-Path: <Ulrich.Windl@rz.uni-regensburg.de>
X-Original-To: ntp@ietfa.amsl.com
Delivered-To: ntp@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id F264B3A0F49 for <ntp@ietfa.amsl.com>; Tue, 14 Apr 2020 13:39:50 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.9
X-Spam-Level:
X-Spam-Status: No, score=-1.9 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 947Hl8Yjcvuu for <ntp@ietfa.amsl.com>; Tue, 14 Apr 2020 13:39:49 -0700 (PDT)
Received: from mx4.uni-regensburg.de (mx4.uni-regensburg.de [IPv6:2001:638:a05:137:165:0:4:4e7a]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 7A1BD3A0F4A for <ntp@ietf.org>; Tue, 14 Apr 2020 13:39:49 -0700 (PDT)
Received: from mx4.uni-regensburg.de (localhost [127.0.0.1]) by localhost (Postfix) with SMTP id 46E5D6000052; Tue, 14 Apr 2020 22:39:45 +0200 (CEST)
Received: from smtp2.uni-regensburg.de (smtp2.uni-regensburg.de [194.94.157.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "smtp.uni-regensburg.de", Issuer "DFN-Verein Global Issuing CA" (not verified)) by mx4.uni-regensburg.de (Postfix) with ESMTPS id BD0E96000051; Tue, 14 Apr 2020 22:39:44 +0200 (CEST)
To: Miroslav Lichvar <mlichvar@redhat.com>
References: <CACsn0c=zzDKP6iBjPJWGF0rkqSaY3AY738ynGwDZO14sdBJ-Bg@mail.gmail.com> <CAJm83bB2A3VUxXX47Y0ubmS9Xne7PRSyV_xHY_D9YvHjqE-vFA@mail.gmail.com> <CACsn0cm3jpKZTUQ=novTgVaFhc1xCJgmUF3oOgdrzQa-HgOCUQ@mail.gmail.com> <CAJm83bAqbMMs2W3SyH+3c17wcC85paY4-_jk2SxczgsxBLyYyA@mail.gmail.com> <CAJm83bAQeR_6U3jgmbWzdus3pu+OO2_KP+M9RtbCFYOfDQy4dw@mail.gmail.com> <DB8PR02MB56111CCA23CDCF97A3C9F3E8CFDD0@DB8PR02MB5611.eurprd02.prod.outlook.com> <4536_1586860567_5E959217_4536_221_1_20200414103543.GC1945@localhost>
Cc: ntp@ietf.org
From: Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>
Message-ID: <9a170387-201a-6ddd-3515-64413f2dee02@rz.uni-regensburg.de>
Date: Tue, 14 Apr 2020 22:37:41 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0
MIME-Version: 1.0
In-Reply-To: <4536_1586860567_5E959217_4536_221_1_20200414103543.GC1945@localhost>
Content-Type: text/plain; charset="utf-8"; format="flowed"
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Archived-At: <https://mailarchive.ietf.org/arch/msg/ntp/8x4Ve6Yf9k79IToaFe1IW8cKTQg>
Subject: Re: [Ntp] [EXT] Re: The bump, or why NTP v5 must specify impulse response
X-BeenThere: ntp@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: <ntp.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ntp>, <mailto:ntp-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/ntp/>
List-Post: <mailto:ntp@ietf.org>
List-Help: <mailto:ntp-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ntp>, <mailto:ntp-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 14 Apr 2020 20:39:51 -0000

On 4/14/20 12:35 PM, Miroslav Lichvar wrote:

[...]
> 
> In the context of NTP, which is supposed to synchronize computer
> clocks, the clock may be an even bigger problem than the network.

Yes, I also realized that our GPS-based startum-1 server basically 
measures room temperature when looking at the frequency correction.

But asymmetric network delays are also an important factor.
[...]

v2.23.0 | Report a Bug | By Email