Re: Predictable Internet Time

Joe Touch <touch@isi.edu> Tue, 03 January 2017 18:25 UTC

Return-Path: <touch@isi.edu>
X-Original-To: ietf@ietfa.amsl.com
Delivered-To: ietf@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 540BE129A80 for <ietf@ietfa.amsl.com>; Tue, 3 Jan 2017 10:25:08 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -10
X-Spam-Level:
X-Spam-Status: No, score=-10 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, RP_MATCHES_RCVD=-3.1] 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 bb8q4uooFVFR for <ietf@ietfa.amsl.com>; Tue, 3 Jan 2017 10:25:07 -0800 (PST)
Received: from boreas.isi.edu (boreas.isi.edu [128.9.160.161]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 487041295DE for <ietf@ietf.org>; Tue, 3 Jan 2017 10:25:07 -0800 (PST)
Received: from [128.9.160.81] (nib.isi.edu [128.9.160.81]) (authenticated bits=0) by boreas.isi.edu (8.13.8/8.13.8) with ESMTP id v03INsvw016813 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NOT); Tue, 3 Jan 2017 10:23:54 -0800 (PST)
Subject: Re: Predictable Internet Time
To: =?UTF-8?B?UGF0cmlrIEbDpGx0c3Ryw7Zt?= <paf@frobbit.se>
References: <CAMm+LwgfQJ8aG5wB=d3fRbbeje3J9o7Z4_DCuP8DL88ouDeKzw@mail.gmail.com> <504e2cea0d1668c31486b05fec0a967a4446aefe@webmail.weijax.net> <CAMm+Lwi_jU6gjdtdM6a2n_9_89tUvWBNXxnMtSjTEA++h1D4Ew@mail.gmail.com> <e0a43370-751f-808c-3719-9716f9cd57d1@isi.edu> <B990A5A4-D62B-4E10-9FF7-7BA4377C0958@frobbit.se>
From: Joe Touch <touch@isi.edu>
Message-ID: <b487d605-6a6d-c5d2-4837-c7847f1c9083@isi.edu>
Date: Tue, 3 Jan 2017 10:23:56 -0800
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1
MIME-Version: 1.0
In-Reply-To: <B990A5A4-D62B-4E10-9FF7-7BA4377C0958@frobbit.se>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 8bit
X-ISI-4-43-8-MailScanner: Found to be clean
X-MailScanner-From: touch@isi.edu
Archived-At: <https://mailarchive.ietf.org/arch/msg/ietf/xWKfQvdSLpzjP-7_ibyIeQWB9H0>
Cc: Phillip Hallam-Baker <phill@hallambaker.com>, IETF Discussion Mailing List <ietf@ietf.org>
X-BeenThere: ietf@ietf.org
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: IETF-Discussion <ietf.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ietf>, <mailto:ietf-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/ietf/>
List-Post: <mailto:ietf@ietf.org>
List-Help: <mailto:ietf-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ietf>, <mailto:ietf-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 03 Jan 2017 18:25:08 -0000

+1

You can deny the ITU all you want, but we are not in control of the time
standards used by financial, governmental, etc. systems.

Note that everything below also assumes a consistent view of time
itself; conversion from "seconds since epoch measured locally" always
needs to be translated to UTC at sea level on Earth anyway.

Time within the machine should be measured relative to its own temporal
frame, but whenever we communicate with another machine we need to
strive to be as close to UTC as possible - warts and all. Anything else
- including and especially smearing - compromises *correct* behavior.

Joe


On 1/2/2017 10:29 PM, Patrik Fältström wrote:
> I think personally, as long as we do have leap seconds:
>
> - we should have the leap second information available somewhere in clear machine readable format. Some suggestions exists, including encoding it in A-records in DNS ;-)
>
> - we should look at having the time since epoch really be the number of SI-seconds since the epoch
>
> - we should have translation between number of seconds and UTC take leap seconds into account
>
> - we should fix the code that do not accept 61 seconds in a minute