Re: [core] [SenML] Multiple values in a measurement

Christian Amsüss <christian@amsuess.com> Thu, 08 November 2018 18:37 UTC

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Date: Thu, 8 Nov 2018 19:37:16 +0100
From: Christian =?iso-8859-1?Q?Ams=FCss?= <christian@amsuess.com>
To: Michael Koster <michaeljohnkoster@gmail.com>
Cc: Shantanoo Desai <des@biba.uni-bremen.de>, "fluffy@cisco.com" <fluffy@cisco.com>, "core@ietf.org" <core@ietf.org>
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Subject: Re: [core] [SenML] Multiple values in a measurement
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Hi Michael,

On Thu, Nov 08, 2018 at 10:17:41AM -0800, Michael Koster wrote:
> I don't believe RFC8428 places any normative constraints on the scope
> of the identifiers that result from bn+n, either in section 4.5.1
> names or 4.6 resolved records. 

Quote:

| Name:  Name of the sensor or parameter.  When appended to the Base
|      Name field, this must result in a globally unique identifier for
|      the resource.

I'm not particularly fond of of that, but remember very clear reasoning
from the authors that having unique IDs in there is a stronger
requirement than playing nice with URI references.

> Specifically, I don't imagine there being a senML validator that would
> check for the uniqueness of bn+n resolved names. I don't even know how
> right offhand.

I figure "We funnel data from all our devices into our Enterprise
server whose database behaves like a concatenation of all SenML files"
was one application. That'd get confused quite fast if different devices
all reported their first accelerometer as "3313/0/".

> What do the authors say?

I'd be very happy to be told I'm wrong on this (it would allow more
elegant core-interfaces), and look forward to a response from them.

Christian

-- 
To use raw power is to make yourself infinitely vulnerable to greater powers.
  -- Bene Gesserit axiom