Re: [v6ops] [EXTERNAL] Re: Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)

Bob Hinden <bob.hinden@gmail.com> Tue, 16 February 2021 03:17 UTC

Return-Path: <bob.hinden@gmail.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 628343A0BFA; Mon, 15 Feb 2021 19:17:03 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.097
X-Spam-Level:
X-Spam-Status: No, score=-2.097 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, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com
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 EplBmXeOSz6R; Mon, 15 Feb 2021 19:17:01 -0800 (PST)
Received: from mail-wr1-x42a.google.com (mail-wr1-x42a.google.com [IPv6:2a00:1450:4864:20::42a]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 2CAC83A0BF9; Mon, 15 Feb 2021 19:17:01 -0800 (PST)
Received: by mail-wr1-x42a.google.com with SMTP id 7so11455146wrz.0; Mon, 15 Feb 2021 19:17:01 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:message-id:mime-version:subject:date:in-reply-to:cc:to :references; bh=7/S3Nz2XWds1pEGALIcxwe1oash7WIugORveB/cPiFA=; b=gkEE27k+u0sNXtQm+SjDNrdOpptMRIhoeTzrsQEUTDhkXCjP0P0Ab8zMO35laCTznX aSrfch80lPYMNjSxqt7SRxgxZoR8RZapzNH5jpKdhO4Rcst7KDvgVYohXYKofiz73tbS shwcpNvbzkFQ7+1npLsr4ZvhL9TO+DNHBCjZpmNnqPV6H9If0HQvOsjteeGdIW/JXw85 /kJXu9ZxtXA9uP8pdbO+0fn5CAYxREDg0MK3fFedKV2cpDweUvuUu1xJ/gSMOlNMkC3d 74Tth78cTyMb6ffbWIWA322+i9W7HmoQc9iV4NcA2+f8bsnw4l1q1NjNgR/fqPPcNWBF 7MPw==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:message-id:mime-version:subject:date :in-reply-to:cc:to:references; bh=7/S3Nz2XWds1pEGALIcxwe1oash7WIugORveB/cPiFA=; b=TQuCqplkFNlEWILher1IWINHOUb4F7gGucEGZ1P75jlZv/FPiVac24uhucNW7tMBFR VYNa2870Hh8TGuUG5KxBceDp68DLoL6KNLAREqYMI2/wfjyJSc81Wqfl1pCMITZU9LR6 TiJoR42DZ9XmG2TEXJlNrJnIIqWAOVfunSydJ6rHco5PT7aEdFs9RTWGStcRwY3Ep6dW rmAx7Urh0fNBqYqKNsDxZR2LDCWGGB17L7vbi0rgliTeVyxqFqHpRC58cVEHOBiDhiqh KIjxaVnNM76GX5cQVe7YxSazFLYFZ+ObnPUiOInpWAKMKcu8y2AsuqxRPyFXMgP4eB5p gXEA==
X-Gm-Message-State: AOAM5300ErV465Q4Tzc2fNdcnsGnqMB7VDEPvb8r3U487LD0zb4mdxo0 AwVcOJf/nzy47CoaIr+wS+4=
X-Google-Smtp-Source: ABdhPJwKg5iDwHiHaor6pP370sgUz9c2+sLmYVz93JFtQUsNZNCQIWD5q8Bs9C3ewWZJddXNP7oVoA==
X-Received: by 2002:adf:e4c3:: with SMTP id v3mr22443644wrm.210.1613445419449; Mon, 15 Feb 2021 19:16:59 -0800 (PST)
Received: from [10.0.0.199] (c-24-5-53-184.hsd1.ca.comcast.net. [24.5.53.184]) by smtp.gmail.com with ESMTPSA id l2sm15617482wrm.6.2021.02.15.19.16.57 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 15 Feb 2021 19:16:58 -0800 (PST)
From: Bob Hinden <bob.hinden@gmail.com>
Message-Id: <7EE1DA6D-0751-48FF-8238-FFEE15CE891E@gmail.com>
Content-Type: multipart/signed; boundary="Apple-Mail=_D824A508-7B6C-4849-95BA-AD5EE6E0B9C0"; protocol="application/pgp-signature"; micalg=pgp-sha512
Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.17\))
Date: Mon, 15 Feb 2021 19:16:55 -0800
In-Reply-To: <98707BCB-C0BF-434A-B6F2-70CE20418CDD@fugue.com>
Cc: Bob Hinden <bob.hinden@gmail.com>, "Manfredi (US), Albert E" <albert.e.manfredi@boeing.com>, Fernando Gont <fgont@si6networks.com>, IPv6 Operations <v6ops@ietf.org>, "6man@ietf.org" <6man@ietf.org>
To: Ted Lemon <mellon@fugue.com>
References: <160989494094.6024.7402128068704112703@ietfa.amsl.com> <6fe3a45e-de65-9f88-808d-ea7e2abdcd16@si6networks.com> <F4E00812-E366-4520-AE17-7BB46E28D575@gmail.com> <CAN-Dau3iOjjU+FLpdtA7nqfKRX+sjjSanAU8U-O3pH-k5nSoig@mail.gmail.com> <a3fbfb94-90ae-961c-a2ab-33ade27e074e@si6networks.com> <672bd5e6-bdce-5915-1082-1ed30d3c5980@gmail.com> <CAN-Dau1CvbwZccq2Zyr8xBkiW1z0nKX_YcGW-y3VL7=pm+wA+w@mail.gmail.com> <227CDF8C-E929-4AA5-9D24-733381EB5C69@fugue.com> <CAN-Dau0JsMJ6Ad1pqeEKSKpRiSXDibMG4yKdVOKL4uFoqi5sAQ@mail.gmail.com> <EED3FE0C-1CE6-4472-895A-7BA6C6A998F3@fugue.com> <4cebe185-0b1b-04c1-4a89-b6c207bb82bb@si6networks.com> <b31c8eddd0c14e539f7c4fb472eb3563@boeing.com> <c0cd20f7-aa40-0053-9056-4df913716ac7@si6networks.com> <d1ea3406ec70488696a091ac1d5d0ff9@boeing.com> <98707BCB-C0BF-434A-B6F2-70CE20418CDD@fugue.com>
X-Mailer: Apple Mail (2.3445.104.17)
Archived-At: <https://mailarchive.ietf.org/arch/msg/v6ops/Afg5XXEMzinMQ2i57UhglSt377U>
Subject: Re: [v6ops] [EXTERNAL] Re: Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)
X-BeenThere: v6ops@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: v6ops discussion list <v6ops.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/v6ops>, <mailto:v6ops-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/v6ops/>
List-Post: <mailto:v6ops@ietf.org>
List-Help: <mailto:v6ops-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/v6ops>, <mailto:v6ops-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 16 Feb 2021 03:17:03 -0000

Hi Ted,

> On Feb 15, 2021, at 2:05 PM, Ted Lemon <mellon@fugue.com> wrote:
> 
> On Feb 15, 2021, at 4:49 PM, Manfredi (US), Albert E <albert.e.manfredi@boeing.com> wrote:
>> Your mention of birthday paradox depends on how many organizations use ULAs. If not many do, then the likelihood of global uniqueness goes up.
> 
> There are also different uses for ULA. ULA can be used for internal addressing by large orgs, and there there’s potential for overlaps, if for no other reason than that large orgs sometimes merge.
> 
> Another use for ULAs is on home networks. In this case, we don’t expect ULAs to ever need to cross the router. So the set of networks on which home network ULAs need to work is very tightly constrained, and we don’t need to worry about ambiguities.

As a datapoint for this, I own two home style routers from different vendors.   Both generate ULA prefixes automatically.   Vendors seem to have figured this out.

Bob


> 
> Another use for ULAs is stub networks. In this case, again we do not expect the ULA to ever make it past the adjacent infrastructure link (the link to which the stub network is attached).
> 
> So chasing after global uniqueness is not necessary in most cases; even in the case where it is possible that there will be conflicts, /global/ uniqueness is not really the issue. In a case where two orgs are merging, the likelihood of a ULA collision, assuming they used a real RNG to generate the ULA, is small, and if it happens, the worst case scenario is that one or both of the orgs need to renumber before they merge. This is not something that’s going to just randomly cause a problem.
> 
> _______________________________________________
> v6ops mailing list
> v6ops@ietf.org
> https://www.ietf.org/mailman/listinfo/v6ops