Re: Proposal to further clarify prefix length issues in I-D.ietf-6man-rfc4291bis

Mark Smith <markzzzsmith@gmail.com> Sat, 11 March 2017 12:52 UTC

Return-Path: <markzzzsmith@gmail.com>
X-Original-To: ipv6@ietfa.amsl.com
Delivered-To: ipv6@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id B6DE81294E3 for <ipv6@ietfa.amsl.com>; Sat, 11 Mar 2017 04:52:21 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: 2.026
X-Spam-Level: **
X-Spam-Status: No, score=2.026 tagged_above=-999 required=5 tests=[DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, FROM_LOCAL_NOVOWEL=0.5, HK_RANDOM_ENVFROM=0.626, HK_RANDOM_FROM=0.999, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=no 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 zvIFU_3EeaAP for <ipv6@ietfa.amsl.com>; Sat, 11 Mar 2017 04:52:20 -0800 (PST)
Received: from mail-ua0-x229.google.com (mail-ua0-x229.google.com [IPv6:2607:f8b0:400c:c08::229]) (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 A3A3D127071 for <ipv6@ietf.org>; Sat, 11 Mar 2017 04:52:20 -0800 (PST)
Received: by mail-ua0-x229.google.com with SMTP id f54so128909189uaa.1 for <ipv6@ietf.org>; Sat, 11 Mar 2017 04:52:20 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=Q3k+bZRn4e26YSWKNr3h1uQUzjFzvO7VtAnTb7O6+As=; b=s8f6g15ynfry7fAYWBqpxcXeQSzDOiNzpzJoQDZH3z4jClfoRHToHwpHY8Mo0mYaRX ZbRBGGYm5M2t3J4QRLOtrDPUZYvYaBokFdvcwm01GRramCWVkdLZMKJmx1givLVI5sMr RIehFKNXm/Nv+z9883Xx5c9WZg4o25Pp/MQqGQUWzab4pjqyZHGxawYDTfopYIw71D5v vXJPpINH9XIe144YKd4qE/Rr87sDFh6fZSOat+lok517lSBQ6AEp5P3IoWOzgICQXLHG V2j4RD5/h6Q8PUwsbbDA2dVfQuwqhxvGHVJXue3f1ObN3yLTWudRjJBz22E9aEGpFOsh AlPg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=Q3k+bZRn4e26YSWKNr3h1uQUzjFzvO7VtAnTb7O6+As=; b=mysVLgJqHDAcb0qbUVPf4YdVXb6IPSCK32lQRUJvNdHDezXdF1I8yVOa2nGZh8F9JG Idd86R31swGNifLay97oxrJ9cGu3utpbpVmMSYv7jauHFkL/a1vdlpeYZK/8ZdSDjewp wrysLGQnod8w4PTtOvYjg4ckxOabcGeeEZy/xXmQ9HcR4kbrNAGfUVV/cGd7ytGsNhNO 3YkOcbcXZ1Qw0atpN8ihWuclDoPJ5b9KUSC2sZ6pUoNxdHT5ehLD04h303exIF05PdHI LwNMegcT1zpnnq57zSzx8j2QRrOGTRgXjzRzdOTN+T5Gp7J1qXn5lfnpt5zlDO7+d+Sn WT3g==
X-Gm-Message-State: AMke39kBFm0LqepHvHQQi5mVwJcdBldp9dFEspOUZCarxr7UOU9dTwdiL4+pmVXbrl9g76GSpUh6XL2oUkCXCA==
X-Received: by 10.159.48.193 with SMTP id k1mr10346458uab.49.1489236739805; Sat, 11 Mar 2017 04:52:19 -0800 (PST)
MIME-Version: 1.0
Received: by 10.159.36.144 with HTTP; Sat, 11 Mar 2017 04:51:49 -0800 (PST)
In-Reply-To: <9f6ea52b7ac741ae9f95e9901d1a3bd1@XCH15-06-11.nw.nos.boeing.com>
References: <0ED54B2A-AF35-4510-9F04-EA2E213634C4@google.com> <m1clw44-0000I4C@stereo.hq.phicoh.net> <9f6ea52b7ac741ae9f95e9901d1a3bd1@XCH15-06-11.nw.nos.boeing.com>
From: Mark Smith <markzzzsmith@gmail.com>
Date: Sat, 11 Mar 2017 23:51:49 +1100
Message-ID: <CAO42Z2wRowud1jmSQkv=osHm5tDSX03cUt9UH0LCj-SCeikYLA@mail.gmail.com>
Subject: Re: Proposal to further clarify prefix length issues in I-D.ietf-6man-rfc4291bis
To: "Manfredi, Albert E" <albert.e.manfredi@boeing.com>
Content-Type: text/plain; charset=UTF-8
Archived-At: <https://mailarchive.ietf.org/arch/msg/ipv6/LQJkspiRtpeU-vAb-lXhoj5wx40>
Cc: "ipv6@ietf.org" <ipv6@ietf.org>
X-BeenThere: ipv6@ietf.org
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: "IPv6 Maintenance Working Group \(6man\)" <ipv6.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ipv6>, <mailto:ipv6-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/ipv6/>
List-Post: <mailto:ipv6@ietf.org>
List-Help: <mailto:ipv6-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ipv6>, <mailto:ipv6-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sat, 11 Mar 2017 12:52:21 -0000

On 10 March 2017 at 06:28, Manfredi, Albert E
<albert.e.manfredi@boeing.com> wrote:
> -----Original Message-----
> From: ipv6 [mailto:ipv6-bounces@ietf.org] On Behalf Of Philip Homburg
>
>> The first interface identifier concept is that for any prefix of
>> length n, the length of the interface identifier is 128-n. Let me
>> call this prefix-iid.
>>
>> The second iid concept is in auto configuration of addresses. I'll
>> call this slaac-iid.
>>
>> The way I see it, any slaac-iid that is based on (pseudo)-random
>> number has to be at least 64 bits. I don't see any reason for more
>> than 64 so exactly 64 sounds about right.
>
> If you want random, a PRNG can create any length of IID. A 48-bit IID would be just as reasonable, and it could be formed from a randomly changing link layer address.
>

You two have read

"Analysis of the 64-bit Boundary in IPv6 Addressing"
https://tools.ietf.org/html/rfc7421

haven't you?

48 bit IIDs were given up between RFC1883 and RFC2373.

<snip>

Regards,
Mark.