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

Brian E Carpenter <> Sat, 13 February 2021 03:08 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 574273A12A6; Fri, 12 Feb 2021 19:08:10 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -2.099
X-Spam-Status: No, score=-2.099 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, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-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 F-DEVJDJKQ3j; Fri, 12 Feb 2021 19:08:09 -0800 (PST)
Received: from ( [IPv6:2607:f8b0:4864:20::42f]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 2EABD3A12A5; Fri, 12 Feb 2021 19:08:09 -0800 (PST)
Received: by with SMTP id w18so690164pfu.9; Fri, 12 Feb 2021 19:08:09 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=subject:to:cc:references:from:organization:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=pr1HxHgfPNW6JPBLeLBmrCRkaghmaenPF9/v2K5Qrk4=; b=RTyGNcymH/ZZg4FaGPWmiQ7KeC3UX0eCyHr1QDZhYlL7JRGqerd6Fgh27TIoqvfoRK TjikTreGsdoM4IPSs9OT2BjCukg47/6dayFtc7UXOnHROLCTCj9pdxGCAwyk1GA4PzXQ LvtirpacPwMC0cARvz1snw84caoSq52KR7kjGM7Q6IBDgm2b9qwjCr2cfxDG2pPKaq1h //ZIUpU6dneA59WI/8QJ0b0/mFfzc8HYHT8Cmo4/LJT9R/dOriW+UBx393e8EHlqL3zb mA38cSy7/V+BGyQvH2BH/M4XhXvIGUDx0RNEYllf2MM6L2uxGGMg/Q8+NnQsQO1NaD0L mC4Q==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:organization :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=pr1HxHgfPNW6JPBLeLBmrCRkaghmaenPF9/v2K5Qrk4=; b=pUTfcaDnvJKgnaVOx6DsvbY7nv8pVVqe52vMY9zxHYaxfE/CZnJymuke/8ep4kMWm0 rDUSM5qLNsloBsOY/hl35KVmeoJQpKQ3pV6j/mkoRT/HP3zLjMfF9mZcm4F+18NUvwjE 96zgebC0bJAX2WqKtXZq0zTYcm66kS/LHgz3hpVEQS77a0iUDoM9EGXpkfhITPvm5FOH WxT/lyQx+iWcrSvl1YSOz1zb+IOZhpSkHe56RTY0gfGismENvl3KRfVrXoCNMZKrVDY2 mFVRduHg8o22xm0DVxULwZtJBbdono0p4/VFNjewiO3Nauv9VF8khhOGNh5ilhd4QyTO 2s4w==
X-Gm-Message-State: AOAM531wWvXQYX8DcYa8EjEn12qT2dvzXfAFzX45e59ocbTZOgzpafts fZA1hhPJhI2kEYGiP293Kgu0YeGh1i7nTA==
X-Google-Smtp-Source: ABdhPJzLkF8YlKB7KFfKBv7oUKExil8Ypx5PJZWtHMfe5RL2/+SDLYVOArJQHGARsQ21eP6rp8pk4w==
X-Received: by 2002:a05:6a00:1707:b029:1cc:2d49:9f29 with SMTP id h7-20020a056a001707b02901cc2d499f29mr5622307pfc.8.1613185686565; Fri, 12 Feb 2021 19:08:06 -0800 (PST)
Received: from [] ([]) by with ESMTPSA id p8sm10457580pgi.21.2021. (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 12 Feb 2021 19:08:05 -0800 (PST)
To: Fernando Gont <>, Ted Lemon <>, Fred Baker <>
Cc: IPv6 Operations <>, "" <>
References: <> <> <> <> <> <> <> <> <> <>
From: Brian E Carpenter <>
Organization: University of Auckland
Message-ID: <>
Date: Sat, 13 Feb 2021 16:08:00 +1300
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1
MIME-Version: 1.0
In-Reply-To: <>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Archived-At: <>
Subject: Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: v6ops discussion list <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Sat, 13 Feb 2021 03:08:11 -0000

OK, I have deleted all the content (but basically I agree with Ted Lemon). IMHO:

ULAs SHOULD be treated exactly like GUAs for all practical purposes (including using a default router for them), with the exception that they MUST be filtered by border routers at a domain boundary that is defined administratively. The only extra requirement is that ULA prefixes MUST be unique within that domain boundary. That's all, I think.

As for the word "scope" and the phrase "global scope" it may be best to not use them at all. We originally had a false notion of concentric rings of address scope, but reality is a very complex Venn diagram. Even link-local may stop being very meaningful as we see more and more mesh networks. That will be much harder to handle than any aspect of ULAs.

   Brian Carpenter