Re: past IAB statement about IPv6 Addressing Architecture

Ran,

On 14/03/2014 05:15, RJ Atkinson wrote:
> <http://www.iab.org/appeals/2003-2/iab-response-to-appeal-against-iesg-action-raised-by-mr-r-elz-appeal-text-february-2003/>
> 
> The Internet Architecture Board (IAB) does multiple things,
> including Internet Architecture, handling appeals of IESG
> decisions, overseeing the RFC publication process, and other matters.
> 
> There was an appeal from Robert Elz to the IAB about a decade ago
> that related to IPv6 and IESG handling of some IPv6 document(s).  
> The IAB response is at the URL above.
> 
> I was an IAB member at that time and directly participated
> in the IAB's review of the claims and also in the IAB's
> decisions about that appeal.  I was not the author of the 
> precise wording used in the IAB's formal response at the
> URL above.
> 
> The IAB definitely had consensus that the IPv6 architecture
> and engineering specifications required a 64-bit IID, that
> this was a fundamental part of the IPv6 architecture, and
> made specific recommendations to the IESG to clarify documents
> accordingly.
> 
> Quoting from part of that IAB statement, specifically from Section:
>> X) The IAB considers that the separation of the Interface-ID from the 
>> Subnet Identifier in IPv6 unicast addresses not starting with binary 000 
>> is a fundamental property of the IPv6 addressing and routing architecture 
>> and should be retained.
> 
> Quoting from part of that IAB statement, specifically from Section 2.3:
>> d) We recommend that, as an update to this document, and via a recommendation
>> to the IESG, that the IPv6 Working Group uses clearer specification language
>> as per RFC-2026 and RFC-2119 to describe the requirement for a 64-bit
>> Interface-ID in IPv6 unicast addresses not starting with binary 000.

The language in the addressing architecture is very explicit on this,
and has been since RFC 3513 (April 2003). Furethermore, the explicit
language is in the archived version of draft-ietf-ipngwg-addr-arch-v3-10.txt
which is *earlier* than the mysterious version 11 mentioned in
kre's appeal. So I find this part of the appeal mysterious.

>>
>> e) We recommend that, via a recommendation to the IESG, that the
>> IPv6 Working Group expeditiously revise RFC-2461 to:
>>
>> specifically note that it is not valid to configure an IPv6 router such
>> that the ‘autonomous configuration’ bit is set to TRUE AND the advertised
>> IPv6 prefix length exceeds 64 bits AND the advertised IPv6 prefix does not
>> start with binary 000,
>>  
>> and also expeditiously revise RFC-2462 to:
>> specifically require that a host ignore a Prefix Advertisement Option 
>> when the first three bits of the advertised IPv6 prefix do not start 
>> with binary 000 AND the advertised IPv6 prefix-length exceeds 64-bits.

This was not done. Apart from anything else, there's no such thing
as a "Prefix Advertisement Option", but even if we replace it by PIO,
RFC 4862 does not appear to say this. I don't recall, but I assume
that there was no consensus for this change in the IPv6 WG.

The evidence is that implementations that support PIO do in fact
accept whatever prefix length is advertised, which conforms
to RFC 4862 IMHO. I don't see this as harmful, because it's
orthogonal to the choice that 64 bits is the IID length in
IPv6-over-foo specs.

> 
> This IAB Appeal Response is specific confirmation that the 
> IPv6 architecture always has had a 64-bit IID.  This IAB response 
> should be cited as a normative reference on this topic in the
> "Why /64" Internet-draft.

We can mention it in the historical summary, but it isn't part
of the normative history of IPv6 (sorry, IAB ;-).

    Brian

> 
> Yours,
> 
> Ran
> 
> 
> 
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