Re: [core] Using CoAP for P2P

John Carter <> Mon, 06 April 2020 20:48 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id DE3D93A08E0 for <>; Mon, 6 Apr 2020 13:48:33 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -2.098
X-Spam-Status: No, score=-2.098 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, HTML_MESSAGE=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (1024-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id rijboe9NTkji for <>; Mon, 6 Apr 2020 13:48:32 -0700 (PDT)
Received: from ( [IPv6:2a00:1450:4864:20::52e]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 49F3A3A08B1 for <>; Mon, 6 Apr 2020 13:48:32 -0700 (PDT)
Received: by with SMTP id a43so1231114edf.6 for <>; Mon, 06 Apr 2020 13:48:32 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=6iaMRbLOQdCiDahEh58Do6qcKmaAKmHIN9lif2Cph/U=; b=Ki+4TqPvY7wtTr1z/FesQCGezQu4AtNFMs6VOL8G5tfUwSf8ZXY19cSczTNAAGvryu Tg5bD3WcHkRYGdnX6TgW9EsJcPnWOG4jeDtpGP2Prjw4lVmV91nWAFCMqK8HGH0oELf5 ZjDPvvYfCWxNDYmgYd64YEym6FXsZu4v4EGBc=
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=6iaMRbLOQdCiDahEh58Do6qcKmaAKmHIN9lif2Cph/U=; b=Kw3tdCoFqtLcub17dV1A7ASGxr+3AyrFLnO8xjws/U5POVyO3hgC9azyok59ZV95gH gAxsxxUg+CReAqLng302v4gEdvCjiEpRSydv0Z33CW72pMa9N8CRvFuxqOiLCtA7Cl/e SV2xFCSdV/UYzOVt3AunLTJH6oSUKBz5A93nxDkAsO01qsABWcL/mOpDT+x7euWm/5ay 4rb4DCdoyPa1pEjCAA7cFd2Fhxoa94I/n0AxDwhZ/8v9rLzZujzFFimONAAvEWGVZltd PVXtzQpazx92FCfLyi9S2iktWSKncAcljQL621STFljXwQXpfpkZMqhWkJHHrNzdx4s1 iy+w==
X-Gm-Message-State: AGi0Puao46BPnAOilv8FjNXiJHwQynwwBH9N8r1LqvtxDuzXgvtCHN4S 6mTvNSPEXEdYYq5rrSjCmZlYJGv1Wlv5/RSmfX6gY9kfw7ByobU8hKUIUXp+t8LuXyagVacuv26 Qyfi1Dd8AeDj7qybX0A==
X-Google-Smtp-Source: APiQypKZAympLPSdjOgpr3BfmSWeZPY594IbVpi8RmYm5qzWU50ScHBlTF2Yt82RyJBQHfLjnYc81cejt/sYEGdQdbA=
X-Received: by 2002:a17:906:5a90:: with SMTP id l16mr1289414ejq.276.1586206110597; Mon, 06 Apr 2020 13:48:30 -0700 (PDT)
MIME-Version: 1.0
References: <>
In-Reply-To: <>
From: John Carter <>
Date: Tue, 07 Apr 2020 08:48:18 +1200
Message-ID: <>
To: Abhijan Bhattacharyya <>
Cc: core <>
Content-Type: multipart/alternative; boundary="000000000000c3696905a2a563b5"
Archived-At: <>
Subject: Re: [core] Using CoAP for P2P
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Constrained RESTful Environments \(CoRE\) Working Group list" <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Mon, 06 Apr 2020 20:48:35 -0000

While the standard is, unlike the http standard, agnostic as to who is the
client and who is the server and the roles can switch.... in practical
experience I'd advise caution.

1. If you are not careful you end up with a system that only works if and
only if all nodes are up and working. The best thing about REST is it
reduces coupling and dependencies between client and server. If you two way
couple them, you have made the coupling a lot stronger.

2. If you are not careful, you can end up with update loops. ie. Node A
updates an observable resource, in response to which Node B updates a
derived observable resource, which Node.... updates a derived observable
resource, which triggers an update on Node A and around we go.

On Thu, Apr 2, 2020 at 12:31 AM Abhijan Bhattacharyya <> wrote:

> Hi,
> Is there any standardized mechanism to use CoAP for a P2P connection?
> Thanks.
> --
> Regards,
> Abhijan Bhattacharyya,
> *Technologist by profession [IoT| Internet Protocols| 5G]*
> _______________________________________________
> core mailing list

John Carter
Phone : (64)(3) 358 6639
Tait Electronics
PO Box 1645 Christchurch
New Zealand

This Communication is Confidential. We only send and receive email on the

basis of the terms set out at