Re: [core] RFC 7967 (No-Response) together with block-wise transfers in CoAP

Carsten Bormann <cabo@tzi.org> Wed, 26 June 2019 11:43 UTC

Return-Path: <cabo@tzi.org>
X-Original-To: core@ietfa.amsl.com
Delivered-To: core@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id A54C01200DB for <core@ietfa.amsl.com>; Wed, 26 Jun 2019 04:43:53 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.197
X-Spam-Level:
X-Spam-Status: No, score=-4.197 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_NONE=0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 5Id-gconJSnx for <core@ietfa.amsl.com>; Wed, 26 Jun 2019 04:43:51 -0700 (PDT)
Received: from smtp.uni-bremen.de (gabriel-vm-2.zfn.uni-bremen.de [134.102.50.17]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 95826120121 for <core@ietf.org>; Wed, 26 Jun 2019 04:43:51 -0700 (PDT)
Received: from [192.168.217.110] (p54A6CA4C.dip0.t-ipconnect.de [84.166.202.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.uni-bremen.de (Postfix) with ESMTPSA id 45Yh4j3WQCzybF; Wed, 26 Jun 2019 13:43:49 +0200 (CEST)
Content-Type: text/plain; charset="utf-8"
Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.1\))
From: Carsten Bormann <cabo@tzi.org>
In-Reply-To: <95486C6F-A08A-487E-974B-5692D474C06B@wittra.se>
Date: Wed, 26 Jun 2019 13:43:48 +0200
Cc: core <core@ietf.org>
X-Mao-Original-Outgoing-Id: 583242206.6311359-f1db63e45bb7266562de534b1f11a3a7
Content-Transfer-Encoding: quoted-printable
Message-Id: <135E11E6-07C7-471B-B2F9-94F875191199@tzi.org>
References: <95486C6F-A08A-487E-974B-5692D474C06B@wittra.se>
To: Fredrik Wegelid <fredrik.wegelid@wittra.se>, Abhijan Bhattacharyya <abhijan.bhattacharyya@tcs.com>
X-Mailer: Apple Mail (2.3445.9.1)
Archived-At: <https://mailarchive.ietf.org/arch/msg/core/CkoKnh3FX-FGihnW8ofYTm2a32w>
Subject: Re: [core] RFC 7967 (No-Response) together with block-wise transfers in CoAP
X-BeenThere: core@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Constrained RESTful Environments \(CoRE\) Working Group list" <core.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/core>, <mailto:core-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/core/>
List-Post: <mailto:core@ietf.org>
List-Help: <mailto:core-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/core>, <mailto:core-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 26 Jun 2019 11:43:54 -0000

Hi Fredrik,

I’m not sure I entirely understand the message exchanges you envision; maybe you can provide an example.

RFC 7967 has a way to suppress responses based on the response code.
Unfortunately, the granularity is on the class only at the moment.
The option that carries this information isn’t explicitly defined as an extension point.  Still, someone (the original author?  The WG?) might want to go ahead, e.g., by defining a bit in the option value that says “Not interested in 2.31 responses”.  (Maybe we want to understand what exactly a client would not be interested in a bit more before we go ahead allocating bits like this.)

Abhijan, what do you think?

Grüße, Carsten


> On Jun 26, 2019, at 13:30, Fredrik Wegelid <fredrik.wegelid@wittra.se> wrote:
> 
> Hi,
> 
> I hope that I am using this email list in the correct way. I apologise if that is not the case.
> I have some questions/thoughts about using the No-Response option (RFC 7967) together with block-wise transfers in COAP.
> 
> In my team we are using CoAP to send messages from devices to a server. The messages are of such a size that we need to make block-wise transfers. In an attempt to reduce the amount of traffic in the network we have looked at using the No-Response option. We are however not clear on how this would work if used together with block-wise transfers. We would like to use the No-Response option to make the server omit the 2.31 Continue responses from the server on each block. We would however still like to be able to get a response on the last block to indicate the status of the entire block sequence. 
> 
> Does this make sense? In RFC 7967 block-wise transfers are not mentioned. Are they meant to be used together?
> 
> Best regards,
> Fredrik Wegelid
> _______________________________________________
> core mailing list
> core@ietf.org
> https://www.ietf.org/mailman/listinfo/core
>