Re: Last Call: <draft-ietf-6man-rfc4291bis-07.txt> (IP Version 6 Addressing Architecture) to Internet Standard

Brian E Carpenter <> Wed, 15 February 2017 21:19 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 6AD2F129B8C; Wed, 15 Feb 2017 13:19:40 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -1.999
X-Spam-Status: No, score=-1.999 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, 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 O1yaD72dShZB; Wed, 15 Feb 2017 13:19:38 -0800 (PST)
Received: from ( [IPv6:2607:f8b0:400e:c05::230]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id CDC551297E8; Wed, 15 Feb 2017 13:19:38 -0800 (PST)
Received: by with SMTP id z67so7923414pgb.1; Wed, 15 Feb 2017 13:19:38 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=subject:to:references:cc:from:organization:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=nh9SNUUpdm9C/xHmZYhUSt0KWBBqFOBF1uOkKXZsXyg=; b=YRIGnOLTUX5FeObc8LFa85D+tuqINzcYE8pZ75+1qr/tTDa/wvxUhDn6zYg+xqOZAo OMs73r+jbmWTOpcp9NhA0AO/ETtCEccF9zq3FjtobEGKcMApWePhGL0Se0OT/QwYS44M 3XPyLFj1ga7ldc6UwyXyg/v4BO+FrAWtHFlBfv8ftAmdRD3lgnXNpBYMQ6PZreRlRf01 kI6BmZB4amzciqHZRsbXlfxxbPGRLnAGQnM9Tr2nte6zzsn5dhw8oGxvFWQqoKTngxH2 c2EwgplWq3NWvKCQ12jliS6tKzdfSBe8V9N6PWbyekqHE3r6v5FBQHmoD4Gr/mYeoYL1 15xA==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=x-gm-message-state:subject:to:references:cc:from:organization :message-id:date:user-agent:mime-version:in-reply-to :content-transfer-encoding; bh=nh9SNUUpdm9C/xHmZYhUSt0KWBBqFOBF1uOkKXZsXyg=; b=N50uOEaP5iqCsKGSuQ7y5VSEtM32ZWX1iXFqCsepKSPp5p+mXKqe2rO2lHxrcbrPgk l/6P+01W/ukw6hsbtvxfTNwixPcRTSQHDmU4ce+u5fJ4p8O4PQGMICw58voLm5LIhv1G RRY36T3PE9VPSMbyPwRGIVS4gzTcYuWqb/NNenN8RRZ08nJVUIs4FtvUUjLKBWIKy7X/ cVJm7YfPXJjRMXWy01zPdallFOgAksBiQy2wdh0m29w4qgxnzHrEM6ZdWeAZPXQhzu8N hwTtOZJgBGU0zpvKo8cTGhmUa16d1HujSP5GRq1JhaniRUDZskCG8W4VvugCpAV02xdl l/Xg==
X-Gm-Message-State: AMke39nL+f8YfIxohlzQO9dF5siABL6HpdGS49dl7ZRv19FqjbvAXqgqE/d5tHOGWaNsRw==
X-Received: by with SMTP id 33mr20815724plg.151.1487193578440; Wed, 15 Feb 2017 13:19:38 -0800 (PST)
Received: from [] ([]) by with ESMTPSA id y6sm9341615pgc.1.2017. (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 15 Feb 2017 13:19:37 -0800 (PST)
Subject: Re: Last Call: <draft-ietf-6man-rfc4291bis-07.txt> (IP Version 6 Addressing Architecture) to Internet Standard
References: <> <> <> <> <> <> <>
From: Brian E Carpenter <>
Organization: University of Auckland
Message-ID: <>
Date: Thu, 16 Feb 2017 10:19:39 +1300
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1
MIME-Version: 1.0
In-Reply-To: <>
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Archived-At: <>
Cc: 6man WG <>, IETF-Discussion Discussion <>, Suresh Krishnan <>,,
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: "IPv6 Maintenance Working Group \(6man\)" <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Wed, 15 Feb 2017 21:19:40 -0000

On 15/02/2017 22:31, wrote:
> Brian,
>>>> Brian, changing the 64 bit boundary is such a big change that I would
>>>> claim it is far outside the scope of advancing 4291 to Internet standard.
>>> Agreed.
>> Of course. The point is only that it's a parameter in the design of SLAAC,
>> whose value is set by the address architecture.
> If your statement is that we only have the 64 bit boundary because of SLAAC I believe you are wrong.
> Can you provide any support for that view?

No, that's not what I'm saying. I'm saying that SLAAC - by design - would work
with any reasonable IID length, but we've chosen to fix it at 64.

> If I understand you correctly, your proposal is to change the fixed 64 bit Interface-ID length in IPv6 to a variable one, with an exception for links where SLAAC is used.

No. At least not in the foreseeable future. But we should allow for the fact that if
prefixes between /64 and /127 are used, routing needs to just work. That's all.

> How do you practically suggest to do this, given the issues raised in ?

I'm not suggesting any change to normal subnets, where all those issues apply.
I can't see how /64 can be changed for them, without changing a great many
> Do you think this change is appropriate in the context of advancing 4291?

I don't think I have suggested text that would lead to a single instruction in
running code being changed.


> Do you have implementation reports and are there not interoperability problems here?
> Best regards,
> Ole