IETF Logo Mail Archive

Re: [Ntp] ntp-over-ptp concerns

"heiko.gerstung@meinberg.de" <heiko.gerstung@meinberg.de> Wed, 13 March 2024 15:44 UTC

Return-Path: <heiko.gerstung@meinberg.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 4489AC14F680 for <ntp@ietfa.amsl.com>; Wed, 13 Mar 2024 08:44:28 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.406
X-Spam-Level:
X-Spam-Status: No, score=-4.406 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_ZEN_BLOCKED_OPENDNS=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01, URIBL_BLOCKED=0.001, URIBL_DBL_BLOCKED_OPENDNS=0.001, URIBL_ZEN_BLOCKED_OPENDNS=0.001] autolearn=unavailable autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=meinberg.de
Received: from mail.ietf.org ([50.223.129.194]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id DlGhkKJRDwcH for <ntp@ietfa.amsl.com>; Wed, 13 Mar 2024 08:44:23 -0700 (PDT)
Received: from server1b.meinberg.de (server1b.meinberg.de [213.239.234.28]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id B8D45C14F617 for <ntp@ietf.org>; Wed, 13 Mar 2024 08:44:21 -0700 (PDT)
Received: from seppmail.py.meinberg.de (unknown [193.158.22.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by server1b.meinberg.de (Postfix) with ESMTPSA id 9F3AC3A00FF8; Wed, 13 Mar 2024 16:44:18 +0100 (CET)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=meinberg.de; s=d2021; t=1710344658; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=wbMmTQnSRqBf/UVTDyXSS1fT8hLjToTxXXUcE8jcySY=; b=I5Jmt3ptoofhXKwEJDx2rlvDnN84xL+ldB2q0kUoMl8kuRoSrY01pRmMa+/S19Yg+ewaKb qeFF2ZRJ1jPbyQOpUHtIi8F0hPCJvTqTXCAozlGNwg/1m8oJ5Fcd4jaXESpYwR5MMddTs+ ZlucuGjSV4s80fAfX/29p2Bra4Pnh7ooBijYByUJh5uZ3FnimGpJbePd3JQAAW29lkDc74 5PHmbO1FkMJOvtzSpjZqQFonZijjsqyWdXs6o1Ku//r9pplQHDoqfX4Pk3IHpDWva9Ir7K M9frkcP+q5PpqwyffjDNR6Qzr7k8jVfZ1R+YbSvc/2Czpi2CbzgoJ/JKZY9tlg==
Received: from seppmail (localhost [127.0.0.1]) by seppmail.py.meinberg.de (Postfix) with SMTP id 4TvvvQ3JyCz36pt; Wed, 13 Mar 2024 16:44:18 +0100 (CET)
Received: from srv-kerioconnect.py.meinberg.de (srv-kerioconnect.py.meinberg.de [172.16.3.65]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by seppmail.py.meinberg.de (Postfix) with ESMTPS; Wed, 13 Mar 2024 16:44:17 +0100 (CET)
X-Footer: bWVpbmJlcmcuZGU=
User-Agent: Microsoft-MacOutlook/16.82.24021813
Date: Wed, 13 Mar 2024 16:44:16 +0100
Message-ID: <7B033A12-5A14-4501-A296-8CD888A54920@meinberg.de>
Thread-Topic: [Ntp] ntp-over-ptp concerns
References: <DM6PR17MB3484BA12E5E0214094779270832B2@DM6PR17MB3484.namprd17.prod.outlook.com> <AM7PR02MB57656DD84240E26C98BAFC95CF2A2@AM7PR02MB5765.eurprd02.prod.outlook.com> <ZfG9Z70isj-QXdQ_@localhost>
In-Reply-To: <ZfG9Z70isj-QXdQ_@localhost>
Importance: Normal
X-Priority: 3
Thread-Index: AZ2x3tU+ODk0MDM1MTc0YjY1YTljYQ==
From: "heiko.gerstung@meinberg.de" <heiko.gerstung@meinberg.de>
To: Miroslav Lichvar <mlichvar@redhat.com>, Doug Arnold <doug.arnold=40meinberg-usa.com@dmarc.ietf.org>
Cc: Rodney Cummings <rodney.cummings@keysight.com>, NTP WG <ntp@ietf.org>
X-SM-outgoing: yes
MIME-Version: 1.0
Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg="sha-256"; boundary="----7F3FDD40C0AA85AEBE08F95C22C851A0"
Archived-At: <https://mailarchive.ietf.org/arch/msg/ntp/Yb1JgrB97JFKo87kgGxPsiJJ09c>
Subject: Re: [Ntp] ntp-over-ptp concerns
X-BeenThere: ntp@ietf.org
X-Mailman-Version: 2.1.39
Precedence: list
List-Id: Network Time Protocol <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, 13 Mar 2024 15:44:28 -0000

Hi,

to remind you why you started NTP-over-PTP in the first place:
- network switches and routers do not support NTP hardware timestamping and do not provide a way to correct for the residence time of NTP packets
- COTS network interface chips do not support hardware timestamping for NTP and therefore do not allow to correct for any delays caused by the network stack and other OS parts

The IEEE1588 working group came to the conclusion that a client-server-variant of PTP can be useful and would combine the advantages of NTP and PTP. 

And yes, the SPTP approach is one possible way of achieving this. CSPTP will be the standardized version which is created by the IEEE 1588 WG.

Regards,
  Heiko



Regards,

Am 13.03.24, 15:51 schrieb "ntp im Auftrag von Miroslav Lichvar" <ntp-bounces@ietf.org <mailto:ntp-bounces@ietf.org> im Auftrag von mlichvar@redhat.com <mailto:mlichvar@redhat.com>>:


On Wed, Mar 13, 2024 at 01:45:02PM +0000, Doug Arnold wrote:
> In principle, one will be able to do with CSPTP what one can do with NTP.


Ok, so CSPTP is reinventing NTP from scratch? Was this effort prompted
by the SPTP announced by Facebook recently? Why not simply adopt NTP
instead? If anything is missing we can specify extension fields.


-- 
Miroslav Lichvar


_______________________________________________
ntp mailing list
ntp@ietf.org <mailto:ntp@ietf.org>
https://www.ietf.org/mailman/listinfo/ntp <https://www.ietf.org/mailman/listinfo/ntp>

v2.23.0 | Report a Bug | By Email