[v6ops] Re: [E] New Version Notification for draft-mishra-v6ops-variable-iids-problem-statement-01.txt
Jeremy Duncan <jduncan@tachyondynamics.com> Thu, 19 September 2024 16:24 UTC
Return-Path: <jduncan@tachyondynamics.com>
X-Original-To: v6ops@ietfa.amsl.com
Delivered-To: v6ops@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id A7EC8C14F6B5 for <v6ops@ietfa.amsl.com>; Thu, 19 Sep 2024 09:24:18 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -7.109
X-Spam-Level:
X-Spam-Status: No, score=-7.109 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, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H2=-0.001, RCVD_IN_ZEN_BLOCKED_OPENDNS=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01, URIBL_DBL_BLOCKED_OPENDNS=0.001, URIBL_ZEN_BLOCKED_OPENDNS=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=tachyondynamics.com
Received: from mail.ietf.org ([50.223.129.194]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id kX5dm96Zcn5h for <v6ops@ietfa.amsl.com>; Thu, 19 Sep 2024 09:24:14 -0700 (PDT)
Received: from NAM10-MW2-obe.outbound.protection.outlook.com (mail-mw2nam10on2118.outbound.protection.outlook.com [40.107.94.118]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id BD1C6C14F68F for <v6ops@ietf.org>; Thu, 19 Sep 2024 09:24:14 -0700 (PDT)
ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=dgGTFH48D0O7kVszEkaShlV4E/BOD0sA7bD10WM3zn1ytec4Q4NJRb2UuopJn6ZMplqzNsOe8mCS4cnmXiiMA7pqzFsV3lzNCzCTLTkL3o+4k6xHAh3kkSd31WYHvOiK8Mui6clUsaTmH9pXllahd+zNW5ItxEQc5MJ1OfqWR+GBhLSDNib/yS6eb/jPEBzLd3A9Xxye2MPxE2DOdd2C5zxjqlXPlO8u7lQIwFYNZ2UeSzQanMgwZhY9TGhZ9k7VSRxks3TeftFKgJIPHvMgkinffl1iiPSGyv7jeRTL4oAdv4rajeXVQnUWBois0xv9itZSSKSOd6QSeRcbT2gHqA==
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=63RQQC/EHOqCKdGxcroOoln7PWThWcDpJCgVXwxFhRw=; b=u6J59KLaIYuMc3jxXSqN7sV/dGe1YbLaXB3m7vcoHp4YDanf520//Rs4HPIHvMz0Xt81M3C/jFEO4W5RnXJepP1bmBkNn024Ec29PKH4SCaKG+Mc5WZ4QOX4gTRZFlglObqWO1cwWw/qcFO+z4eIQGUctYvxwkKhXw1J26EzmW84B+60GSLXzTGxQSzKRYzU8LpAuPOnx0EHWHQBxDDnGQaDRYNdTsdi5QmSufg38sMw6kJxXxrRvIBF3n2DQa1LiA59/84I+627J8Q1xxRx4AtYRsuHwydvEqXRkJ1VSjCHKk67rXCXn6UMgRjpuYireA3CLX3wDblWpyLSHrKEDA==
ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=tachyondynamics.com; dmarc=pass action=none header.from=tachyondynamics.com; dkim=pass header.d=tachyondynamics.com; arc=none
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tachyondynamics.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=63RQQC/EHOqCKdGxcroOoln7PWThWcDpJCgVXwxFhRw=; b=OxBsH+iolGYkFywndC7G9/BJTsuVAo/8JymUegy+ZE7hMrPH/nJpAXOn87NXfGRc7KshjilMEILlFddFPZt1KshgfJFhYq3NLqaJijP+U8t7xR8D8a3X2fEpJ1oJLxhL+sc+bVrFnrl2A/2tfiD91EAos3jf4c6Xh91/5O0RiUE=
Received: from BL1PR18MB4277.namprd18.prod.outlook.com (2603:10b6:208:308::11) by SA1PR18MB5995.namprd18.prod.outlook.com (2603:10b6:806:3e5::9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7962.24; Thu, 19 Sep 2024 16:24:11 +0000
Received: from BL1PR18MB4277.namprd18.prod.outlook.com ([fe80::e357:79f4:f41a:c329]) by BL1PR18MB4277.namprd18.prod.outlook.com ([fe80::e357:79f4:f41a:c329%7]) with mapi id 15.20.7982.016; Thu, 19 Sep 2024 16:24:11 +0000
From: Jeremy Duncan <jduncan@tachyondynamics.com>
To: Gert Doering <gert@space.net>
Thread-Topic: [v6ops] Re: [E] New Version Notification for draft-mishra-v6ops-variable-iids-problem-statement-01.txt
Thread-Index: AQHbCobyfE1hxn6QJESxKkQOmjr9f7JfOeKAgAAD1ICAAAXegIAABAsggAACXACAAAGtIA==
Date: Thu, 19 Sep 2024 16:24:11 +0000
Message-ID: <BL1PR18MB427773F64F722CD554AB369AAC632@BL1PR18MB4277.namprd18.prod.outlook.com>
References: <CABNhwV1dspJRUZ15eX0sWupEAg+pLAp-3GMA5dEKF-X04MwQRw@mail.gmail.com> <CABNhwV0zP5C2uCcki=g7WDb_0Aqs8Q=15SV1r8yNM3E7-b+fVg@mail.gmail.com> <eb8789d5-dab1-af90-b40a-672d27d26198@foobar.org> <ZusLvEDEBs7R4HOt@Space.Net> <CAKD1Yr3qdqMNPJa7bietzat5HFM4g=OLHeJQgvc+tktd4+rW8w@mail.gmail.com> <A83B7972-6937-42FF-947F-47A9C0E8DBA5@gmail.com> <CAO42Z2ySu5mAFg26ZJR5sPFnYrgB3wCkYaA72RzMFNKKQr5fpg@mail.gmail.com> <ZuxEdwwAw4EkvDH7@Space.Net> <f74270ff-ba7b-40d7-8fc3-45a24613c8be@nsrc.org> <BL1PR18MB4277A9F29C8D3A98D324E5D0AC632@BL1PR18MB4277.namprd18.prod.outlook.com> <ZuxOwr-PEqF-wLbc@Space.Net>
In-Reply-To: <ZuxOwr-PEqF-wLbc@Space.Net>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
authentication-results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=tachyondynamics.com;
x-ms-publictraffictype: Email
x-ms-traffictypediagnostic: BL1PR18MB4277:EE_|SA1PR18MB5995:EE_
x-ms-office365-filtering-correlation-id: 1bc47dfc-a609-4d1c-0087-08dcd8c77e98
x-ms-exchange-senderadcheck: 1
x-ms-exchange-antispam-relay: 0
x-microsoft-antispam: BCL:0;ARA:13230040|376014|366016|1800799024|10070799003|38070700018;
x-microsoft-antispam-message-info: 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
x-forefront-antispam-report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BL1PR18MB4277.namprd18.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(366016)(1800799024)(10070799003)(38070700018);DIR:OUT;SFP:1102;
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: 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
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-OriginatorOrg: tachyondynamics.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: BL1PR18MB4277.namprd18.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 1bc47dfc-a609-4d1c-0087-08dcd8c77e98
X-MS-Exchange-CrossTenant-originalarrivaltime: 19 Sep 2024 16:24:11.3357 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 306ea27d-bb9d-47c1-a6ca-c70495fc7695
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: ZSFXso/jGsCy9Jxvi/gx+TizUpXAwiI+e6i8ssRV9wTwuYUZAeKTXg/exeW/1LVK8TgsayoGKou8r7UHlp2g4wxZOGAQxfSa7YmQMQ2C4rE=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA1PR18MB5995
Message-ID-Hash: 2YBS4WUPVC6SESC3ISWM3T4HZSVXLYPV
X-Message-ID-Hash: 2YBS4WUPVC6SESC3ISWM3T4HZSVXLYPV
X-MailFrom: jduncan@tachyondynamics.com
X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-v6ops.ietf.org-0; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header
CC: Lorenzo Colitti <lorenzo=40google.com@dmarc.ietf.org>, IPv6 Operations <v6ops@ietf.org>
X-Mailman-Version: 3.3.9rc4
Precedence: list
Subject: [v6ops] Re: [E] New Version Notification for draft-mishra-v6ops-variable-iids-problem-statement-01.txt
List-Id: v6ops discussion list <v6ops.ietf.org>
Archived-At: <https://mailarchive.ietf.org/arch/msg/v6ops/fJNaPLbDQptL70Y-jq0QvaJtOwY>
List-Archive: <https://mailarchive.ietf.org/arch/browse/v6ops>
List-Help: <mailto:v6ops-request@ietf.org?subject=help>
List-Owner: <mailto:v6ops-owner@ietf.org>
List-Post: <mailto:v6ops@ietf.org>
List-Subscribe: <mailto:v6ops-join@ietf.org>
List-Unsubscribe: <mailto:v6ops-leave@ietf.org>
I didn't say infinite I said it's not a problem that we need to solve in the next 1,000 years.
-Jeremy
-----Original Message-----
From: Gert Doering <gert@space.net>
Sent: Thursday, September 19, 2024 12:18 PM
To: Jeremy Duncan <jduncan@tachyondynamics.com>
Cc: Brian Candler <brian@nsrc.org>; Gert Doering <gert@space.net>; Mark Smith <markzzzsmith@gmail.com>; Lorenzo Colitti <lorenzo=40google.com@dmarc.ietf.org>; IPv6 Operations <v6ops@ietf.org>
Subject: Re: [v6ops] Re: [E] New Version Notification for draft-mishra-v6ops-variable-iids-problem-statement-01.txt
Hi
On Thu, Sep 19, 2024 at 04:11:28PM +0000, Jeremy Duncan wrote:
> That???s a disingenuous argument. It???s like saying we need to care for the amount of sunlight we receive because it???s going to run out??? in like 2-3 billion years???
Do the math. IPv6 is far from infinite with the way people keep "rounding up because there is enough" left and right.
Gert Doering
-- NetMaster
--
have you enabled IPv6 on something today...?
SpaceNet AG Vorstand: Sebastian v. Bomhard, Ingo Lalla,
Karin Schuler, Sebastian Cler
Joseph-Dollinger-Bogen 14 Aufsichtsratsvors.: A. Grundner-Culemann
D-80807 Muenchen HRB: 136055 (AG Muenchen)
Tel: +49 (0)89/32356-444 USt-IdNr.: DE813185279
- [v6ops] Fwd: [E] New Version Notification for dra… Gyan Mishra
- [v6ops] Re: [E] New Version Notification for draf… Gert Doering
- [v6ops] Fwd: [E] New Version Notification for dra… Gyan Mishra
- [v6ops] Re: Fwd: [E] New Version Notification for… Daryll Swer
- [v6ops] Re: Fwd: [E] New Version Notification for… Brian E Carpenter
- [v6ops] Re: Fwd: [E] New Version Notification for… Daryll Swer
- [v6ops] Re: Fwd: [E] New Version Notification for… Nick Hilliard
- [v6ops] Re: Fwd: [E] New Version Notification for… Gyan Mishra
- [v6ops] Re: Fwd: [E] New Version Notification for… Gert Doering
- [v6ops] Re: Fwd: [E] New Version Notification for… Nick Buraglio
- [v6ops] Re: Fwd: [E] New Version Notification for… Brian E Carpenter
- [v6ops] Re: Fwd: [E] New Version Notification for… Nick Buraglio
- [v6ops] Re: Fwd: [E] New Version Notification for… Nick Hilliard
- [v6ops] Re: Fwd: [E] New Version Notification for… Lorenzo Colitti
- [v6ops] Re: Fwd: [E] New Version Notification for… Lorenzo Colitti
- [v6ops] Re: [E] New Version Notification for draf… Ivan Pepelnjak
- [v6ops] Re: [E] New Version Notification for draf… Mark Smith
- [v6ops] Re: [E] New Version Notification for draf… Daryll Swer
- [v6ops] Re: [E] New Version Notification for draf… Daryll Swer
- [v6ops] Re: [E] New Version Notification for draf… Gert Doering
- [v6ops] Re: [E] New Version Notification for draf… Brian Candler
- [v6ops] Re: [E] New Version Notification for draf… Jeremy Duncan
- [v6ops] Re: [E] New Version Notification for draf… Gert Doering
- [v6ops] Re: [E] New Version Notification for draf… Jeremy Duncan
- [v6ops] Re: [E] New Version Notification for draf… Jeremy Duncan
- [v6ops] Re: [E] New Version Notification for draf… Jeremy Duncan
- [v6ops] Re: [E] New Version Notification for draf… Gert Doering
- [v6ops] Re: [E] New Version Notification for draf… Gert Doering
- [v6ops] Re: [E] New Version Notification for draf… Jeremy Duncan
- [v6ops] Re: Fwd: [E] New Version Notification for… Brian E Carpenter
- [v6ops] Re: [E] New Version Notification for draf… Philipp S. Tiesel
- [v6ops] Re: [E] New Version Notification for draf… Gert Doering
- [v6ops] Re: [E] New Version Notification for draf… Brian Candler
- [v6ops] Re: [E] New Version Notification for draf… Brian E Carpenter
- [v6ops] Re: [E] New Version Notification for draf… Gert Doering
- [v6ops] Re: [E] New Version Notification for draf… Daryll Swer
- [v6ops] Re: [E] New Version Notification for draf… Gert Doering
- [v6ops] Re: [E] New Version Notification for draf… Lorenzo Colitti
- [v6ops] Re: [E] New Version Notification for draf… Lorenzo Colitti
- [v6ops] Re: [E] New Version Notification for draf… Philipp S. Tiesel
- [v6ops] Re: [E] New Version Notification for draf… Daryll Swer
- [v6ops] Re: [E] New Version Notification for draf… Gert Doering
- [v6ops] Re: [E] New Version Notification for draf… Lorenzo Colitti
- [v6ops] Re: [E] New Version Notification for draf… Daryll Swer
- [v6ops] Re: [E] New Version Notification for draf… Daryll Swer
- [v6ops] Re: [E] New Version Notification for draf… Nick Buraglio
- [v6ops] Re: [E] New Version Notification for draf… Brian E Carpenter
- [v6ops] Re: [E] New Version Notification for draf… Jeremy Duncan