Subject: [core] WGLC observe comment: responsiveness to unacknowledged confirmable notifications

From: "Peter A. Bigot" <[email-masked]>
Date: Wed, 16 Oct 2013 12:54:42 -0500

Several places in observe-11 state that a client's failure to
acknowledge a confirmable notification will cause the client to be
removed from the list of observers, but the timeliness of that result is
not clear: "after several transmission attempts" (section 1.2)
"eventually remove" (section 3.5).

Only the steps in section 4.5, which are conditional on the resource
changing while a notification is outstanding, specify that the client
should be dropped if a confirmable message remains unacknowledged after
its last retransmission ("last attempt to deliver a notification").

The timeliness of dropping the client should not depend on a resource
changing during the process of notification transmission.  Somewhere it
should be made clear that the client is dropped the first time it fails
to acknowledge a confirmable message within the EXCHANGE_LIFETIME, 
either by reworking the steps 4.5 to not be conditional or by putting 
the requirement somewhere else.

Peter

---

From: Klaus Hartke <[email-masked]>
Date: Wed, 16 Oct 2013 21:38:12 +0300

Hi Peter,

good catch. Section 4 of observe-11 indeed never states the
requirement to remove the client when the last transmission attempt
times out, as hinted at in the previous sections. I've opened ticket
#350 for this <http://tools.ietf.org/wg/core/trac/ticket/350>.

Best regards,
Klaus

On 16 October 2013 20:54, Peter A. Bigot <[email-masked]> wrote:
> to acknowledge a confirmable message within the EXCHANGE_LIFETIME, either by
> reworking the steps 4.5 to not be conditional or by putting the requirement
> somewhere else.
>
> Peter