Re: [core] [Last-Call] Last Call: <draft-ietf-core-senml-more-units-02.txt> (Additional Units for SenML) to Proposed Standard

Carsten Bormann <> Tue, 22 October 2019 15:50 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id E5C94120145; Tue, 22 Oct 2019 08:50:15 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -4.199
X-Spam-Status: No, score=-4.199 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id bdI7rRZyH_oL; Tue, 22 Oct 2019 08:50:13 -0700 (PDT)
Received: from ( []) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 9A2D71200E7; Tue, 22 Oct 2019 08:50:13 -0700 (PDT)
Received: from [] ( []) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by (Postfix) with ESMTPSA id 46yHyW4M1MzySN; Tue, 22 Oct 2019 17:50:11 +0200 (CEST)
Content-Type: text/plain; charset=utf-8
Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.1\))
From: Carsten Bormann <>
In-Reply-To: <>
Date: Tue, 22 Oct 2019 17:50:11 +0200
Cc: Cullen Jennings <>,,, IETF <>, core <>,
X-Mao-Original-Outgoing-Id: 593452209.385865-e1671ccef4f53aeffa15a70caec5bfc7
Content-Transfer-Encoding: quoted-printable
Message-Id: <>
References: <> <> <>
To: Pete Resnick <>
X-Mailer: Apple Mail (2.3445.9.1)
Archived-At: <>
Subject: Re: [core] [Last-Call] Last Call: <draft-ietf-core-senml-more-units-02.txt> (Additional Units for SenML) to Proposed Standard
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Constrained RESTful Environments \(CoRE\) Working Group list" <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Tue, 22 Oct 2019 15:50:16 -0000

On Oct 22, 2019, at 17:33, Pete Resnick <> wrote:
> Implementations are perfectly capable of multiplying and adding.

I think after 40+ years in the industry I can refute that statement :-)

But, seriously, this draft is based on a specific request from an SDO, OMA/IPSO, for which this secondary registry would enable porting their existing data models to ones based on the SenML units registry.  Other SDOs from this space might follow suit.

Clearly, when we did SenML, we didn’t want to go this route.  Currently, there is an amazing pull towards data model harmonization that has changed the fundamentals enough that this draft now makes sense.  I’ll leave it to IPSO people to explain this in more details.

“MAY, but SHOULD NOT” means exactly what it says; I don’t think there is a contradiction.
But of course we can contract this to “SHOULD NOT” if that helps.  Oh, and “cm” isn’t registered yet because OMA didn’t need it, not because it couldn’t be registered if that turns out to be desirable.

SenML is now in a position to play a centerpiece in the harmonized IoT data landscape.  Not going for this draft is likely to thwart this opportunity.

Grüße, Carsten