Matt, Ari, and Harri,
While you give good support for adding these units, and I am OK with
that idea, do you have any objection to adding them to the main
registry, which was the other suggestion that Cullen made? I still have
not seen a convincing argument not to make these part of the main
registry.
pr
On 28 Oct 2019, at 10:40, Gillmore, Matthew wrote:
Hi Cullen,
I am the chair of the IPSO working group in OMA and also support what
Ari wrote. During the last IETF in Montreal, stakeholders from the
IPSO working group along with the Core working group met and it was
consensus amongst both working groups that the second registry is how
we would like to move forward.
Cheers,
Matt
-----Original Message-----
From: ietf <ietf-bounces@xxxxxxxx> On Behalf Of Ari Keränen
Sent: Tuesday, October 22, 2019 6:37 PM
To: Cullen Jennings <fluffy@xxxxxx>
Cc: core-chairs@xxxxxxxx; IETF Crazy <ietf@xxxxxxxx>; core
<core@xxxxxxxx>; draft-ietf-core-senml-more-units@xxxxxxxx
Subject: Re: [core] Last Call:
<draft-ietf-core-senml-more-units-02.txt> (Additional Units for SenML)
to Proposed Standard
Hi Cullen,
Carsten already replied to some of these issues later in the thread,
but let me add some more viewpoints.
On 22. Oct 2019, at 17.06, Cullen Jennings <fluffy@xxxxxx> wrote:
I am strongly opposed to the secondary registry - it will
significantly harm interoperability. This could be resolved by not
adding the items in the secondary repository or by adding them to the
main repository.
Having a registry of stuff that may or may not work simply means that
we will have less interoperability because what you can not decide
what is valid SenML or not. Sure some of the device vendors making
things that produce SenML have thought this was a good idea in the
past but I’d like to hear from a bunch of the people that have to
process the SenML data that is produced and see if they think it is a
good idea.
Both registries would work and their use would result in valid SenML.
In a sense the second registry is almost the same as "adding them to
the main repository", but having the second registry enables us to
give better guidance which units to use/prefer and also provide the
translation to the "main registry units".
The working group discussed this for a long time and was against the
items that are being added to the secondary repository.
If there is a large group of people that agree the consensus has
changed, then this should simply be put in the main registry. Many
people believe that since SenML is not meant to be human readable,
having a canonical form of just meters with a floating point number
is better than having both km, mm, and god only knows what else.
Yes, the canonical form of "just meters" is still the recommended way
in general, but that approach did not work as well as we hoped for all
use cases. For example when your sensor value is always in integers of
mm/h, it's more convenient and efficient to send integer values than
multiples of 2.777e-7. Also in many use cases there is a
well-established scaled unit that is used in the industry and forcing
to use a different one didn't turn out to be very productive (we can
still recommend, though, and that's one of the reasons why we are
proposing an additional registry). Finally, legacy models that use
non-scaled units but would like to use SenML as the wire format and
units registry would be expensive to update to use only non-scaled
units.
I note the secondary repository add mm but not cm. How is this
insanity going to work out? How will analytics code trying to process
this data know what it can use or not use. If we are going down this
path, this is the wrong way to do it. The right way is to define a
set of all SI prefixes and say they can be used with any unit.
Any implementation should not try to use anything that is not in the
IANA registry. We did also consider to enable all SI prefixes, but
concluded that it is still useful to have the smallest reasonable set
of units to facilitate interoperability. If there's a real use case
that uses a unit with SI prefix that is missing, it can be simply
registered. Also not all units in the additional registry would work
with just different SI prefix (e.g., min or dBm).
Cheers,
Ari
On Oct 16, 2019, at 11:42 AM, The IESG <iesg-secretary@xxxxxxxx>
wrote:
The IESG has received a request from the Constrained RESTful
Environments WG
(core) to consider the following document: - 'Additional Units for
SenML'
<draft-ietf-core-senml-more-units-02.txt> as Proposed Standard
The IESG plans to make a decision in the next few weeks, and
solicits
final comments on this action. Please send substantive comments to
the ietf@xxxxxxxx mailing lists by 2019-10-30. Exceptionally,
comments may be sent to iesg@xxxxxxxx instead. In either case,
please
retain the beginning of the Subject line to allow automated sorting.
Abstract
The Sensor Measurement Lists (SenML) media type supports the
indication of units for a quantity represented. This short document
registers a number of additional unit names in the IANA registry for
Units in SenML. It also defines a registry for secondary units that
cannot be in SenML's main registry as they are derived by linear
transformation from units already in that registry; RFC 8428 is
updated to also accept these units.
The file can be obtained via
https://urldefense.proofpoint.com/v2/url?u=https-3A__datatracker.ietf
.org_doc_draft-2Dietf-2Dcore-2Dsenml-2Dmore-2Dunits_&d=DwIGaQ&c=pqcuz
KEN_84c78MOSc5_fw&r=UdGshIy7O85QbjoqbIdb_K7GJN4Vxe8yisqNq0oQtS4&m=1HS
mPnFlr7WEiLKKLxMke_BtKIEXMq-xPdsDRzT3I1k&s=wIciltspG7rnX8nThlkp4SeFlD
uiYAwaeqZEOxVBC9Y&e=
IESG discussion can be tracked via
https://urldefense.proofpoint.com/v2/url?u=https-3A__datatracker.ietf
.org_doc_draft-2Dietf-2Dcore-2Dsenml-2Dmore-2Dunits_ballot_&d=DwIGaQ&
c=pqcuzKEN_84c78MOSc5_fw&r=UdGshIy7O85QbjoqbIdb_K7GJN4Vxe8yisqNq0oQtS
4&m=1HSmPnFlr7WEiLKKLxMke_BtKIEXMq-xPdsDRzT3I1k&s=cS56g5iiq-KyNYhVVTz
l1c5-ZTApK90BoaWReY-zR3Y&e=
No IPR declarations have been submitted directly on this I-D.
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