Re: [6tsch] payload format for CoAP

Xavier Vilajosana Guillen <xvilajosana@eecs.berkeley.edu> Sat, 05 October 2013 20:45 UTC

Return-Path: <xvilajosana@berkeley.edu>
X-Original-To: 6tsch@ietfa.amsl.com
Delivered-To: 6tsch@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 1681021F9CC5 for <6tsch@ietfa.amsl.com>; Sat, 5 Oct 2013 13:45:14 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.976
X-Spam-Level:
X-Spam-Status: No, score=-2.976 tagged_above=-999 required=5 tests=[AWL=-0.000, BAYES_00=-2.599, FM_FORGED_GMAIL=0.622, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-1]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id VYmQZtYVGYRr for <6tsch@ietfa.amsl.com>; Sat, 5 Oct 2013 13:45:10 -0700 (PDT)
Received: from mail-pb0-f46.google.com (mail-pb0-f46.google.com [209.85.160.46]) by ietfa.amsl.com (Postfix) with ESMTP id 592AE21F9CB5 for <6tsch@ietf.org>; Sat, 5 Oct 2013 13:45:09 -0700 (PDT)
Received: by mail-pb0-f46.google.com with SMTP id rq2so5416449pbb.5 for <6tsch@ietf.org>; Sat, 05 Oct 2013 13:45:01 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:reply-to:in-reply-to:references :date:message-id:subject:from:to:cc:content-type; bh=2KAxgJE+S5EBJlYHLf6RT44dGoeAWoHumYaAKdBNqAE=; b=YvQloFhiwB9rkArs+CVcJvBfsVASCxxfGSeaa+1MOFiW0CMp4TtpK40G4COb6Pav5z 7dBV8wuwBGAhEpXbo+dREe/b+DCZGEpRBsVguUQJSbFQYqrw/G7vY8F86C6OsFFZXgFI gFKGStea4CDXkyzZS7WrssONgQIQcfKmRbLAxQWv/w2eWbfd2FaD7VnP1KL6FN1GcWse g/Qq4vcoRNLfy/qp7/HBovkkaInULJLXgJXx+f9XaenQN2CNiDUVgETpgJkqR7yr/HVu QkZy6reqMsdhGiJ4hxd0TQVBE8CbpIGCaBl+66cus3SVoDtL0ORIOtcwk1d6CCT26nkV OJUg==
X-Gm-Message-State: ALoCoQkL9bI0fmF0Mm+2Gz8gAY4kvN0Swl4skuKqfs86fnbDVqyUeOTN160Ogvk1uJH2yPqZsYHk
MIME-Version: 1.0
X-Received: by 10.68.215.38 with SMTP id of6mr21842890pbc.14.1381005901737; Sat, 05 Oct 2013 13:45:01 -0700 (PDT)
Received: by 10.70.34.44 with HTTP; Sat, 5 Oct 2013 13:45:01 -0700 (PDT)
In-Reply-To: <C5D823CD-BBE8-473E-A0A0-42C8121EE500@tzi.org>
References: <2C3A8CAFDCAFCA41B8BF705CD9471C5B18609FCD@xmb-rcd-x04.cisco.com> <C5D823CD-BBE8-473E-A0A0-42C8121EE500@tzi.org>
Date: Sat, 5 Oct 2013 13:45:01 -0700
Message-ID: <CALEMV4Z5Aq0TV8E2AE-fadTYqW_cJbYdunZp7b3d9G0-r+vBzQ@mail.gmail.com>
From: Xavier Vilajosana Guillen <xvilajosana@eecs.berkeley.edu>
To: Carsten Bormann <cabo@tzi.org>
Content-Type: multipart/alternative; boundary=001a11346638357c4104e8047e93
Cc: "Raghuram Sudhaakar \(rsudhaak\)" <rsudhaak@cisco.com>, "6tsch@ietf.org" <6tsch@ietf.org>
Subject: Re: [6tsch] payload format for CoAP
X-BeenThere: 6tsch@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
Reply-To: xvilajosana@eecs.berkeley.edu
List-Id: "Discuss link layer model for Deterministic IPv6 over the TSCH mode of IEEE 802.15.4e, and impacts on RPL and 6LoWPAN such as resource allocation" <6tsch.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/6tsch>, <mailto:6tsch-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/6tsch>
List-Post: <mailto:6tsch@ietf.org>
List-Help: <mailto:6tsch-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/6tsch>, <mailto:6tsch-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sat, 05 Oct 2013 20:45:14 -0000

Hi Carsten

can we have access to a cbor parser implementation to do some testing in a
very small microcontroller (e.g msp430).

thanks!
Xavi




On Sat, Oct 5, 2013 at 9:02 AM, Carsten Bormann <cabo@tzi.org> wrote:

> On Oct 5, 2013, at 17:29, "Raghuram Sudhaakar (rsudhaak)" <
> rsudhaak@cisco.com> wrote:
>
> >       • the additional overhead of a CBOR parser. NVPs are easy to parse.
>
> CBOR is easy to parse, too.
>
> To inject some data here, if you are talking about code size overhead:
> size -m cn-cbor.o
>         Section (__TEXT, __text): 880
>
> If all you need is name-value pairs, a tailored CBOR parser will be even
> less than those 880 bytes, which is armv7 code for a fully generic parser
> (for instance, this code includes an implementation of half-precision
> floating point.).
>
> For every single application, it is of course easy to come up with a
> bespoke format that has some advantages over CBOR but only works for this
> application, and we engineers of course like doing that :-).
> Your node may need to do other things in addition to exchanging 6tisch
> data.
> So you already may have a CBOR parser in your constrained device, which
> could make the incremental cost for using it with 6tisch near zero.
>
> Grüße, Carsten
>
> _______________________________________________
> 6tsch mailing list
> 6tsch@ietf.org
> https://www.ietf.org/mailman/listinfo/6tsch
>