[core] PubSub - Questions round 1

Jim Schaad <ietf@augustcellars.com> Thu, 14 September 2017 04:11 UTC

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From: Jim Schaad <ietf@augustcellars.com>
To: draft-ietf-core-coap-pubsub@ietf.org
CC: core@ietf.org
Date: Wed, 13 Sep 2017 21:10:34 -0700
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Subject: [core] PubSub - Questions round 1
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1  I am not clear what the visibility of the intermediate subtopic notes
should be.  Should these nodes appear in the link list when doing a GET on
the root of the pub-sub tree?  Should these nodes appear when doing a
discovery on /.well-known/core?

2.  I would appreciate a discussion for section 5 (resource directory) on
what the trade-offs for publishing items into a resource directory?  What
sets of nodes does it make sense to publish vs not publish - topics of
discussion would include intermediate nodes and max-age for nodes that might
disappear quickly.

3.  When doing discovery, I am not sure if you examples are correct.  My
understanding is that since a URI path is being returned as part of the link
format rather than a full path, the client is supposed to interpret this
value using the GET path as the context of the path.   This would be rule c
of section 2.1 of RFC6690.  This rule seems to have been modified for the
/.well-known/core to say only use the scheme + authority and ignore the path
to the resource.  However, I do not believe that this rule is suspended in
this case.  This means that the return value for figure 4 would be
"</currentTemp>;rt=temperature;ct=50".   Do you believe that I am wrong?

4.  Just because I don't understand.  In RFC 6690  - what is the origin for
rule (b)?  I would have thought this was the target URI value itself, but in
that case I would expect that (b) should be before (a) if it has a schema
and thus is an absolute path.

Jim