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

Ted Lemon <> Wed, 06 January 2021 12:17 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 801823A03EE for <>; Wed, 6 Jan 2021 04:17:39 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -1.897
X-Spam-Status: No, score=-1.897 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, HTML_MESSAGE=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: (amavisd-new); dkim=pass (2048-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id V1_c0eO_a-rM for <>; Wed, 6 Jan 2021 04:17:37 -0800 (PST)
Received: from ( [IPv6:2607:f8b0:4864:20::d2e]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id B04D03A03EB for <>; Wed, 6 Jan 2021 04:17:37 -0800 (PST)
Received: by with SMTP id i18so2536539ioa.1 for <>; Wed, 06 Jan 2021 04:17:37 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20150623; h=from:message-id:mime-version:subject:date:in-reply-to:cc:to :references; bh=4LlZbIUceEaVckEvBwddjJ9hRtWzsxnSprME/90jWOA=; b=uTdOfJ1HYvu8mCXpj+YDIp4V+Z5+qJD6mieOhxjFl7snIlTbXS+0rxTYIvtlrr1W3T +W+kdQX7tIDMffJ8KGSKzAYYtguoZDJ+sZu+iWBg3lRLmzHER9QSDi6fFGDZLhFDAwlg kANkkZ1BIyZgdyXRiaMqGaiNbWKGiWbXw83q4a5GaB8kDNNJXW8Rg7e98IIShpbjR14D RBWo/s2uD6hwRGj6eW+okdfBrd1ozxrZgtK3es1unD4REMliZyfpGkZh/GUPwjVq8ujy Z1cQW+jOlmd1tOiVtQQZaWauraHpIMJmoKGc+G+sAln/RXf2/6OyL8I7VAYGBt+GTOPN M2fg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=x-gm-message-state:from:message-id:mime-version:subject:date :in-reply-to:cc:to:references; bh=4LlZbIUceEaVckEvBwddjJ9hRtWzsxnSprME/90jWOA=; b=qppReHkT4n79KS7K3ZILu8nJtto+pz8py/P5vLldRY9S/ASJawSr6w2IpABH/cQ6Y3 mcq0O+q0Xr7mMJH02p2Pie0LWsN4lpOyuMSzStbmq/rEwLF4JOoVQnTreftqOyy7Kftu 9gw58bLxN2C1YhgyXTPD0BoDdUBBO09b+Ow7SHZkRS4zqcvDcCuxxECL/0r/+WinFpgR ruPNQg6d6nuGkvlmdHPN73JugI664a4fBhds7ura7YkZ79zwX1cjiWOR7lBWL2pGw0PS cdIcQsg7lwufXI9yddRocZEESY8XmYusq4gPd92d/1x8agQ+YCWa7FHvbk3D2V1ZEryC 6Ctg==
X-Gm-Message-State: AOAM531ESXfJnDsvbkcuVow0NoSHNSN990n50r0NLXl0rhhOJne7COaA 80l+jf0WPTeSyQhdPxH0KbyXKQ==
X-Google-Smtp-Source: ABdhPJxJsngGd9akaIiVZjq97k/GB1FRzARSuG/2+EZ86+DgDmsLhhGWtnEG9h9rNJ5O7GqCt5bu2A==
X-Received: by 2002:a6b:4f13:: with SMTP id d19mr2603904iob.121.1609935456681; Wed, 06 Jan 2021 04:17:36 -0800 (PST)
Received: from mithrandir.lan ( []) by with ESMTPSA id r12sm1908049ile.59.2021. (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 06 Jan 2021 04:17:35 -0800 (PST)
From: Ted Lemon <>
Message-Id: <>
Content-Type: multipart/alternative; boundary="Apple-Mail=_10497EDE-6AC7-4BB4-BBC2-0FE624F2F492"
Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.\))
Subject: Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)
Date: Wed, 6 Jan 2021 07:17:33 -0500
In-Reply-To: <>
Cc: Fernando Gont <>, IPv6 Operations <>, "" <>
To: David Farmer <>
References: <> <> <>
X-Mailer: Apple Mail (2.3654.
Archived-At: <>
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "IPv6 Maintenance Working Group \(6man\)" <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Wed, 06 Jan 2021 12:17:40 -0000

On Jan 5, 2021, at 11:38 PM, David Farmer <> wrote:
> I think this is the right direction the previous draft indirectly defined a new scope "non-global", I much prefer explicitly defining a new local scope.

Actually, I think you’ve got it right here: the scope is “non-global.”

> I would add something like the following to better define the relationship between the three scopes;
> The boundary of the link-local scope is strongly defined, limiting the extent of the link-local scope to an individual link. However, in contrast, the boundary of the local scope is weakly defined, it is amorphous and imprecise. In some instances, the extent of the local scope can be a single site, in other instances, a group of unrelated sites, a single organization, or even a cooperating group of organizations. Furthermore, the extent of an individual instance of the local scope doesn't necessarily remain constant, it may expand or contract over time as the local situation dictates, for example when two organizations merge. Nevertheless, the extent of the local scope doesn’t encompass the entirety of the Internet which the global scope does.

There is at least one obvious problem with this definition: the term “local.” ULAs aren’t really local, despite the name. Using the name “local” is what leads to this confusion. Consider this taxonomy:

GUA: “valid everywhere on the internet scope”
ULA: “not valid everywhere scope”
LLA: “valid only on this link scope”

Of course these names are awkward, but I hope they are clarifying. A ULA is “not valid everywhere.” That’s really all you can say about it. You can’t put a ULA prefix in a global routing domain. You can put it in a site routing domain. You can put it in a multi-site routing domain. You can not route it at all. All these uses are valid.

So I don’t really object to your text, but I do object to the name “local.” How about “explicit”? That is, the scope of a ULA is explicit, in the sense that it must be _made_ explicit by the user(s) of the ULA? If that doesn’t work, I’m sure we can come up with a more agreeable term, but please let it not be “local.” Sorry to be a sticky wicket. :)