[Ntp] Wtrlt: NTv5 and polling interval

Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de> Wed, 14 April 2021 07:11 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 []) by ietfa.amsl.com (Postfix) with ESMTP id D92963A10AD for <ntp@ietfa.amsl.com>; Wed, 14 Apr 2021 00:11:44 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.901
X-Spam-Status: No, score=-1.901 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([]) by localhost (ietfa.amsl.com []) (amavisd-new, port 10024) with ESMTP id HYXxOZzOFHpg for <ntp@ietfa.amsl.com>; Wed, 14 Apr 2021 00:11:42 -0700 (PDT)
Received: from mx4.uni-regensburg.de (mx4.uni-regensburg.de []) (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 3B29D3A10AC for <ntp@ietf.org>; Wed, 14 Apr 2021 00:11:40 -0700 (PDT)
Received: from mx4.uni-regensburg.de (localhost []) by localhost (Postfix) with SMTP id 6453A6000057 for <ntp@ietf.org>; Wed, 14 Apr 2021 09:11:36 +0200 (CEST)
Received: from gwsmtp.uni-regensburg.de (gwsmtp1.uni-regensburg.de []) by mx4.uni-regensburg.de (Postfix) with ESMTP id 3C0E06000055 for <ntp@ietf.org>; Wed, 14 Apr 2021 09:11:34 +0200 (CEST)
Received: from uni-regensburg-smtp1-MTA by gwsmtp.uni-regensburg.de with Novell_GroupWise; Wed, 14 Apr 2021 09:11:34 +0200
Message-Id: <607695A4020000A100040673@gwsmtp.uni-regensburg.de>
X-Mailer: Novell GroupWise Internet Agent 18.3.1
Date: Wed, 14 Apr 2021 09:11:32 +0200
From: "Ulrich Windl" <Ulrich.Windl@rz.uni-regensburg.de>
To: "ntp@ietf.org" <ntp@ietf.org>
References: <607692F2020000A10004066D@gwsmtp.uni-regensburg.de>
Mime-Version: 1.0
Content-Type: multipart/mixed; boundary="=__Part5F5E44B4.0__="
Archived-At: <https://mailarchive.ietf.org/arch/msg/ntp/OGfxU7meJbaNn9aA350jieF8JOM>
Subject: [Ntp] Wtrlt: NTv5 and polling interval
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: Wed, 14 Apr 2021 07:11:45 -0000

Sorry, the first address was undeliverable, so I'm trying this one.

--- Begin Message ---

I feel there's an issue with NTPv4 and the polling interval (see attached image):
After a host reboot, the polling interval goes up while "the sync" is not stable yet, so it goes down again, then going up again, etc.
Maybe the polling interval is going up too early and going down too late.
(In the graph you also see some "micro clock hopping effect" that I really couldn't tame in the LAN)
I'm attaching another graph that shows that clock hopping in more detail.

It would be great if those issues could be addressed in NTPv5.


--- End Message ---