Subject: [core] Observe clarification

From: Jim Schaad <[email-masked]>
Date: Wed, 5 Aug 2020 10:53:32 -0700

In section 4.5 the text "A notification can be sent in a confirmable or a
non-confirmable message."  Depending on how you read this, the notification
could also be sent in an ACK piggyback message as well.  That is you CAN do
this, but you don't have to.  The text "A notification is sent in a
confirmable or non-confirmable message." Would have the connotation that
these are the only allowable options.

I believe that the latter is what the text was intending to say, but I do
not know that is true.

Comments?

Jim

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From: Achim Kraus <[email-masked]>
Date: Wed, 5 Aug 2020 21:48:06 +0200

Hi Jim,

I hope, that the later interpretation is the right one.

A notification as an ACK-piggybacked would allocate the request MID,
that would have strange consequences.

best regards
Achim

Am 05.08.20 um 19:53 schrieb Jim Schaad:
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From: <[email-masked]>
Date: Wed, 5 Aug 2020 21:31:59 +0100

Hi Jim,

As I read RFC7641 the initial request with Observe:0 can have the response
in an ACK piggyback.  However, this response is not an Observe notification
- it is the current representation.

4.1.  Request

   A GET request with an Observe Option set to 0 (register) requests the
   server not only to return a current representation of the target
   resource, but also to add the client to the list of observers of that
   resource.  Upon success, the server returns a current representation
   of the resource and MUST keep this representation updated (as
   described in Section 1.3) as long as the client is on the list of
   observers.

When an Observer notification is triggered, this can only be Confirmable or
Non-confirmable.

Regards

Jon

> -----Original Message-----
> From: core [mailto:[email-masked]] On Behalf Of Achim
> Kraus
> Sent: 05 August 2020 20:48
> To: Jim Schaad; [email-masked]
> Subject: Re: [core] Observe clarification
> 
> Hi Jim,
>