IETF Logo Mail Archive

Re: [lp-wan] IID computation for SCHC over LoRaWAN

Olivier Gimenez <ogimenez@semtech.com> Mon, 27 January 2020 09:38 UTC

Return-Path: <ogimenez@semtech.com>
X-Original-To: lp-wan@ietfa.amsl.com
Delivered-To: lp-wan@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 93F11120133 for <lp-wan@ietfa.amsl.com>; Mon, 27 Jan 2020 01:38:30 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.899
X-Spam-Level:
X-Spam-Status: No, score=-1.899 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HTML_IMAGE_RATIO_02=0.001, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_PASS=-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 g142LRYv1fQS for <lp-wan@ietfa.amsl.com>; Mon, 27 Jan 2020 01:38:28 -0800 (PST)
Received: from mail1.bemta24.messagelabs.com (mail1.bemta24.messagelabs.com [67.219.250.213]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 57034120132 for <lp-wan@ietf.org>; Mon, 27 Jan 2020 01:38:28 -0800 (PST)
Received: from [100.112.135.85] (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256 bits)) by server-1.bemta.az-b.us-west-2.aws.symcld.net id 59/9B-11790-29FAE2E5; Mon, 27 Jan 2020 09:38:26 +0000
X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrCJsWRWlGSWpSXmKPExsXiofbjue6k9Xp xBttes1hM6f7JaHHw92l2izez7C1mTHnH6MDiMWP9emaPKb83snosWfKTyaPl2Um2AJYo1sy8 pPyKBNaMFa8nMhfcfMpc8ffBctYGxlM3mbsYuTiEBB4xSmxadZEJwnnBKLHi3mw2CGcno8St7 ofsXYycHGwCOhL/n89i7WJk5xARkJFYXwtSwiwwjVFi9uPXLCAlwgLWEl/3d4OViwjYSHzv6W WEsP0k7l3eywpiswioSsy42w1WzytgJbH3824WiF2/mSQWNV1hBklwCgRKNNx/C9bAKCAm8f3 UGiYQm1lAXOLWk/lgtoSAiMTDi6fZIGxRiZeP/7GCDJIQOMYiMfn5B1aIhILExWlbGCGaayS2 7OphhtgsKHFy5hOwK4QEFCVapy1knsAoNgvJjllIWmYhaYGIJ0rsu/6HEcLWkViw+xMbhK0ts Wzha2YY+8yBx0yY4joSv791QdUrSty+OpV1FjgklzBK9HdMYYcpOvzkFgtM0RRgJCxg5F3FaJ FUlJmeUZKbmJmja2hgoGtoaKRraGyia2RkqJdYpZukV1qsW55aXKJrpJdYXqxXXJmbnJOil5d asokRmIRSCtru7mC8svy93iFGSQ4mJVHeabP14oT4kvJTKjMSizPii0pzUosPMcpwcChJ8Mas A8oJFqWmp1akZeYAEyJMWoKDR0mEVxUkzVtckJhbnJkOkTrF6M0x4eXcRcwcB4/OA5LfmxcCy Xc/FwPJj6uWgERApBBLXn5eqpQ47921QCMEQEZklObBLYAl9kuMslLCvIwMDAxCPAWpRbmZJa jyrxjFORiVhHmPgEzhycwrgbvjFdCJTEAnvhEDO7EkESEl1cAUkvn05ot1WYqtu7eq1Tl8Uk6 JtI8xE9cXE3yXEZqb8vFHo++8z182Pbu4Mr2T9f2pE7qMav9rnQ6uP3dnnuXO8tAdjm/KrRJm 5/bWH9A9f2xR8YTAWUKfC086/T/VsScnfHucx2nhLSKWEb++eS1LOhGYvW/WZKYvbHw/Du1P3 mrA7ML9oPxsLPeS7ttO9s82eot5Shi8cbcWkrvYfnjz1AAVvuNGbH0/EhMXflf5qrDxZa3bbC W5hZomOXMeHZ/178znZWxfM7N19rbsLVbLvNWXm+G8rUzcQco5Udxo38RjkYGMq8v1RGYaT/w m/ExDye3CkfJGhnfr3QoX/GzytBduf235PNN1EleHerISS3FGoqEWc1FxIgB5Mx1IZwQAAA==
X-Env-Sender: ogimenez@semtech.com
X-Msg-Ref: server-16.tower-345.messagelabs.com!1580117904!585255!1
X-Originating-IP: [72.38.248.231]
X-SYMC-ESS-Client-Auth: outbound-route-from=pass
X-StarScan-Received:
X-StarScan-Version: 9.44.25; banners=semtech.com,-,-
X-VirusChecked: Checked
Received: (qmail 20986 invoked from network); 27 Jan 2020 09:38:25 -0000
Received: from s72-38-248-231.static.datacom.cgocable.net (HELO ca01exedge1.semnet.dom) (72.38.248.231) by server-16.tower-345.messagelabs.com with ECDHE-RSA-AES256-SHA384 encrypted SMTP; 27 Jan 2020 09:38:25 -0000
Received: from CA01MAIL1.semnet.dom (10.2.50.40) by ca01exedge1.semnet.dom (192.168.34.22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_RSA_WITH_AES_256_GCM_SHA384) id 15.1.1034.26; Mon, 27 Jan 2020 04:38:20 -0500
Received: from ca01mail2.semnet.dom (10.2.50.41) by CA01MAIL1.semnet.dom (10.2.50.40) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1034.26; Mon, 27 Jan 2020 04:38:22 -0500
Received: from ca01mail2.semnet.dom ([fe80::fdc8:c457:b09e:605d]) by ca01mail2.semnet.dom ([fe80::fdc8:c457:b09e:605d%22]) with mapi id 15.01.1034.026; Mon, 27 Jan 2020 04:38:22 -0500
From: Olivier Gimenez <ogimenez@semtech.com>
To: lp-wan <lp-wan@ietf.org>
CC: "dominique.barthel@orange.com" <dominique.barthel@orange.com>, Ivaylo Petrov <ivaylo@ackl.io>, "Pascal Thubert (pthubert)" <pthubert@cisco.com>
Thread-Topic: [lp-wan] IID computation for SCHC over LoRaWAN
Thread-Index: AQHVxwCYJQu0prjDVk6FFGBv03UPPKfidDIAgAAAYACAEmKf8IAAk6uAgAjkeog=
Date: Mon, 27 Jan 2020 09:38:22 +0000
Message-ID: <087f048de6394ac6828e66291bc1c608@semtech.com>
References: <11567_1578583345_5E174531_11567_198_1_DA3D02FA.6E7E3%dominique.barthel@orange.com> <11889_1578583565_5E17460D_11889_448_5_DA3D0478.6E7F1%dominique.barthel@orange.com> <MN2PR11MB35653D0A24CAE9BB7C8A6B1ED8390@MN2PR11MB3565.namprd11.prod.outlook.com> <e3a0968b393740ac9dc290175d5073a9@semtech.com>, <CAJFkdRyRsuNtC_AZkgqy2APJ_W503MkHCO6JdtF_+9DZKjaYpg@mail.gmail.com>
In-Reply-To: <CAJFkdRyRsuNtC_AZkgqy2APJ_W503MkHCO6JdtF_+9DZKjaYpg@mail.gmail.com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach: yes
X-MS-TNEF-Correlator:
x-dg-ref: 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
x-originating-ip: [10.144.16.38]
Content-Type: multipart/related; boundary="_004_087f048de6394ac6828e66291bc1c608semtechcom_"; type="multipart/alternative"
MIME-Version: 1.0
Archived-At: <https://mailarchive.ietf.org/arch/msg/lp-wan/mj3ojnhJEFX2leMDJThI8VkmtwY>
Subject: Re: [lp-wan] IID computation for SCHC over LoRaWAN
X-BeenThere: lp-wan@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Low-Power Wide Area Networking \(LP-WAN\), also known as LPWA or Low-Rate WAN \(LR-WAN\)" <lp-wan.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/lp-wan>, <mailto:lp-wan-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/lp-wan/>
List-Post: <mailto:lp-wan@ietf.org>
List-Help: <mailto:lp-wan-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/lp-wan>, <mailto:lp-wan-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 27 Jan 2020 09:38:31 -0000

Hi,



According to Wikipedia<https://en.wikipedia.org/wiki/Birthday_problem#Probability_table> for 64 bits IID:

  *   when 190 000 devices are in the network, collision probability is one out of a billion
  *   when 6 100 000 devices are in the network, collision probability is one out of a million

I am still convinced that we should not add any specification/code complexity with such low numbers, anyway we wonder if another approach can be used:

Please see attached picture, the gateway can be seen as a NAT router: the device is able to compute its IP address based on devEUI or whatever we find relevant, which will be unique inside an IPv6 network (but will not change over time or be obfuscated), then IP used outside LoRaWAN network is computed in the SCHC gateway, this way an address collision is detected in the gateway and a new IP can be generated.
Another pro is there is no more need to provision the network prefix into the device

Any thoughts ?

Thank you
Olivier

[cid:image001.png@01D5D4FD.E24206D0]

To view our privacy policy, including the types of personal information we collect, process and share, and the rights and options you have in this respect, see www.semtech.com/legal.

v2.23.0 | Report a Bug | By Email