Re: [core] Comments on draft-hartke-coap-observe-00

Zach Shelby <zach@sensinode.com> Mon, 05 July 2010 06:48 UTC

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From: Zach Shelby <zach@sensinode.com>
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Date: Mon, 05 Jul 2010 09:48:08 +0300
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To: Robert Cragie <robert.cragie@gridmerge.com>
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Subject: Re: [core] Comments on draft-hartke-coap-observe-00
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On Jul 4, 2010, at 8:20 PM, Robert Cragie wrote:

> Sorry these are a little late.
> 
> To summarize:
> 	• The document moves around layers of abstraction somewhat. Some of the concepts are quite abstract (observer, subject etc.), then it talks about messages, then it refers to reliable UDP. I think it should keep to the abstract level and defer discussion on the more specific layers to other documents

Definitely. In the next version I would like to see two parts to the document actually. 1. The requirements and purely abstract model (using sane terminology).  2. The solution for doing subscription using coap-01 (so it still makes it before the -01 cutoff). We decided to move the solution to the next version of coap-observe to avoid contaminating the base coap document while it is perfected. The goal is to move the feature to coap-02 after Maastricht. 

> 	• I know I have said this before but I believe it is important to abstract the transaction model from the methods themselves. This means we can put a clean break between the RESTful part (plus pub/sub) and the transactions (HTTP-like or more asynchronous for M2M). What may be missing is to specify abstract properties of the delivery, which is sort of addressed by message types in this document.

Bingo! This is exactly what we have done in coap-01, so far it seems to work nicely, and it even further simplified the header.

Zach

> I tried to attach as modified original but I think it was too large for mail server. In the attachment my comments are in as <RCC></RCC>. <snip> indicates where I have put out text not directly relevant to the comment.
> 
> Robert
> -- 
> Robert Cragie (Pacific Gas & Electric)
> 
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-- 
Zach Shelby, Chief Nerd, Sensinode Ltd.
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