Subject: Re: [core] Multicast and error codes

From: Carsten Bormann <[email-masked]>
Date: Sun, 6 Nov 2011 17:40:51 +0100

Matthieu,

thanks for reporting this; I have opened ticket #177 for this:

	http://trac.tools.ietf.org/wg/core/trac/ticket/177

Please see my work-in-progress response there.

Grüße, Carsten

On Oct 25, 2011, at 18:08, [email-masked] wrote:

> Hi all,
> 
> In section 4.1 multicast of coap 03 there is a proposition to eliminate 
> responses with an error code
> 
> This text has been removed in 07 and the text "SHOULD be a Non-confirmable 
> request" is now a "MUST be Non-confirmable request".
> But as I understand coap 07 it is possible to send a response with an 
> error code to a NON request as a NON response.
> So I think the text in coap 03 is now missing to avoid response floods.
> What do you think?
> 
> Matthieu
> _______________________________________________
> core mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/core

---

From: [email-masked]
Date: Mon, 7 Nov 2011 10:16:21 +0100

Hi Carsten,

>This needs to be defined
> a bit better, I think (even an empty 2.04 might qualify for a "not
> applicable" here, say in a link-format request with a query. 

I agree the term error code is rather restrictive. The "not applicable" 
flag may be relevant for success codes too.
Typically any response without payload has little value for a multicast 
request. But this condition might be simplistic as the options might 
provide useful information too. For example the location option in a "2.01 
Created" response to a POST or any new fancy option that may come later as 
an extension to the core spec. Anyway do you think that sending a 
non-idempotent multicast request is something wise?

> Note that
> section 4.1 of draft-ietf-core-link-format-07.txt also has something to
> say about multicast.
I agree that draft-ietf-core-link-format-07.txt should probably avoid 
empty responses to a multicast request.

Regards,
Matthieu