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RE: [TF-AP]: Using CoAP for bi-directional communication

From: Nilsson, Claes1 <Claes1.Nilsson@sonymobile.com>
Date: Mon, 14 Sep 2015 22:39:46 +0200
To: 'Carsten Bormann' <cabo@tzi.org>
CC: "public-wot-ig@w3.org" <public-wot-ig@w3.org>
Message-ID: <6DFA1B20D858A14488A66D6EEDF26AA303DBEB6409B6@seldmbx03.corpusers.net>
Thanks Carsten!

I am not familiar with the IETF work on standardizing CoAP over TCP. Just for my understanding, if a device is capable of running TCP is the memory and processing requirements much lower for CoAP over TCP than using Web Sockets? Or is the main architecture for CoAP over TCP a GW running CoAP over TCP on the cloud side and CoAP over UDP on the local constrained side?


Claes Nilsson
Master Engineer - Web Research

Sony Mobile Communications
Tel: +46 70 55 66 878


> -----Original Message-----
> From: Carsten Bormann [mailto:cabo@tzi.org]
> Sent: den 13 september 2015 16:12
> To: Nilsson, Claes1
> Cc: public-wot-ig@w3.org
> Subject: Re: [TF-AP]: Using CoAP for bi-directional communication
> Generally, yesterday's IPv4 NATs require the use of TCP for reasonably
> efficient NAT traversal.  The need for supporting that legacy is one of
> the two reasons why we are standardizing CoAP over TCP (the other one
> is for backend usage).
> Websockets is not a protocol I would expect to see used on a
> constrained device.  (There is indeed a draft specification for CoAP
> over Websockets, but that is really for use in Web browsers, which as
> of today don't speak CoAP over UDP or DTLS directly.)
> Grüße, Carsten
Received on Monday, 14 September 2015 20:40:18 UTC

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