Subject: Re: AAAA/A6 thing

From: Robert Elz <[email-masked]>
Date: Tue, 01 May 2001 16:09:47 +0700

Date:        Mon, 30 Apr 2001 17:08:40 -0700
    From:        "SCHUBERT,EBENEZER (HP-Cupertino,ex1)" <[email-masked]>
    Message-ID:  <[email-masked]>

  | 	Is there any alternate solution to A6 record
  |       being looked at ? Something which lies somewhere
  |       in between AAAA and A6. 

The obvious thing there would simply be to add some restrictions to the
use of A6.   One currently proposed is to only use A6 0,xxx (which makes
it isomorphic to AAAA - but at least using the new record format, so
upgrading to something a bit more complex later would not be impossible).

Another would be to require all of the domains listed to be in the same
zone as the A6 record (so the whole chain can always be returned in one
DNS reply), and/or perhaps limiting the length of the chain (partly for the
same reason).

I doubt very much that it makes sense to invent something new - we already
have the simplest of all possible results (AAAA) and the most general we
can think of at the minute anyway (A6).  Something neither simple, nor general
doesn't seem likely to be a useful aim.

kre

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From: [email-masked]
Date: Tue, 01 May 2001 18:22:09 +0900

>upgrading to something a bit more complex later would not be impossible).

	this part i don't really understand.  if we advocate "A6 0 <128bit>"
	there will be resolver implementation that does not chase A6 chains
	at all (like for cellphones or whatever).  if there's no need,
	there'll be no code.  then, there will be no possibility for "A6
	<non-zero> <less-than-128bit> <chain>".  so I don't really see benefit
	of "A6 0 <128bit>" than "AAAA".

itojun

---

From: Robert Elz <[email-masked]>
Date: Tue, 01 May 2001 16:39:37 +0700

Date:        Tue, 01 May 2001 18:22:09 +0900
    From:        [email-masked]
    Message-ID:  <[email-masked]>

  | 	this part i don't really understand.  if we advocate "A6 0 <128bit>"
  | 	there will be resolver implementation that does not chase A6 chains
  | 	at all (like for cellphones or whatever).

I had thought of adding to my message (but I wanted to keep it reasonably
brief) that the full resolver implementations are still needed now, in
the way we decide we need them to operate - which might be via an AAAA
recursive query to a back end resolver (I would expect that most baby devices
will use back end resolvers to do most of the work for IPv6, just as they
have for IPv4 - whether that includes synthesising AAAA from A6 queries though
hasn't been decided, but it certainly has been contemplated).

The advantage of A6 0 is that it would guarantee operational stability to
at least the degree of AAAA - not that it will simplify the implementation
effort (which only needs to be done a smallish number of times in the grand
scheme of things).

kre

---

From: "SCHUBERT,EBENEZER (HP-Cupertino,ex1)" <[email-masked]>
Date: Mon, 30 Apr 2001 17:08:40 -0700

hi,

	Is there any alternate solution to A6 record
      being looked at ? Something which lies somewhere
      in between AAAA and A6. 

-ebi

> -----Original Message-----
> From: David Terrell [mailto:[email-masked]]
> Sent: Monday, April 30, 2001 9:25 AM
> To: Masataka Ohta
> Cc: D. J. Bernstein; [email-masked]; 
> [email-masked]
> Subject: Re: AAAA/A6 thing
> 
> 
> On Mon, Apr 30, 2001 at 06:16:21PM +0859, Masataka Ohta wrote:
> > Dan;
> > 
> > It's your problem.
> > 
> > > Paul A Vixie writes:
> > > > i have not, yet, heard anything new against A6 in this 
> round of the debate.
> > > 
> > > http://cr.yp.to/djbdns/killa6.html
> > 
> > How about:
> > 
> > 	aol.com.	NS	ns0.aol.net.
> > 	aol.com.	NS	ns1.aol.net.
> > 
> > 	aol.net.	NS	ns0.aol.com.
> > 	aol.net.	NS	ns1.aol.com.
> > 
> > ?
> 
> In this case, ns[01].aol.{net,com} will be in the {net,com} zones as 
> glue.
> 
> I think the question that I have yet to see answered that Dan is
> not articulating well is "how the hell is DNS glue supposed to work
> sanely with A6?"  I can't find an answer to that myself.  Everybody's
> talking about no full IP addresses written anywhere, and DNS
> delegation is one place where that just doesn't work.  You need the
> full 128 bit address in there, and glue registry is the one place
> that these addresses can't change frequently, because of the bulk
> of TLD zones and complicated, time consuming procedures registrars
> use to update those records... 
> 
> -- 
> David Terrell            | "I went into Barnes and Noble to 
> look for a 
> Prime Minister, Nebcorp  | book on A.D.D., but I got bored and left." 
> [email-masked]             | - Benjy Feen
> http://wwn.nebcorp.com/  |
> 
> 
> to unsubscribe send a message to 
> [email-masked] with
> the word 'unsubscribe' in a single line as the message text body.
>

---

From: Christian Schild <[email-masked]>
Date: Wed, 02 May 2001 09:57:49 +0200 (CEST)

Itojun,

>       of "A6 0 <128bit>" than "AAAA".

one can still 'advocate' A6 0 <128bit> with the chain resolution implemented.
In my understanding we should suggest to use 128bit records for _now_. If 
in the future, with more testing done and more experience at hand, we have 
developed a good set of rules how to chain A6 records in an unperilous
manner, then we could start to _use_ the chaining.  

Christian

---

From: Ian Jackson <[email-masked]>
Date: Thu, 3 May 2001 18:32:15 +0100 (BST)

Christian Schild writes ("Re: AAAA/A6 thing"):
> one can still 'advocate' A6 0 <128bit> with the chain resolution
> implemented.  In my understanding we should suggest to use 128bit
> records for _now_. If in the future, with more testing done and more
> experience at hand, we have developed a good set of rules how to
> chain A6 records in an unperilous manner, then we could start to
> _use_ the chaining.

That's a hopeless idea.

We should not add features to standards without a clear idea of what
they're good for.  We should not put something in the spec and then
tell people not to use it.  If people shouldn't use it it shouldn't be
in the spec.

Furthermore, deploying A6 0 will not allow anyone to effectively work
the bugs out of prefix-chasing resolvers, so if we were to specify
A6 0 now but decided we wanted A6 >0 later we'd have to wait for new
implementations anyway.  Also, if the spec says A6 but MUST NOT
require prefix chasing, many implementors may avoid implementing it
altogether.

Another way to look at it as a bait-and-switch: we are supposed to
agree to A6 now, despite there being no good reason for it, because
actually `we'll just use A6 0'.  But, everyone still has to implement
A6 >0 !

Ian.

---

From: Jim Bound <[email-masked]>
Date: Thu, 3 May 2001 23:41:09 -0400 (EDT)

After much good discussion with Davkd Conrad and Paul Vixie, and
Christian/Matts view of this I believe we must implement what we have
regarding A6 specs from the implementation perspective.  I will leave it
to others to tell us as we develop this if the specs are to be altered.
Assist with renumbering.  Reduce routing tables.  And make IPv6 more
deployable.  I will leave it to others to find consensus on this or
against this.  It needs to be implemented and used.

/jim

---

From: Ian Jackson <[email-masked]>
Date: Fri, 4 May 2001 14:55:42 +0100 (BST)

Jim Bound writes ("Re: AAAA/A6 thing"):
> regarding A6 specs from the implementation perspective.

`After much good discussion with various people, I believe we must
implement what we have regarding AAAA specs from the implementation
perspective'.

Just because something is Proposed Standard doesn't mean it should be
implemented and/or advanced to Draft Standard.

AAAA is Proposed Standard too, has more operational experience, is
simpler, and can do everything that A6 can do just as well if not
better.

>  I will leave it to others to tell us as we develop this if the
> specs are to be altered.

The A6 spec hasn't been finalised yet.  It hasn't even been approved
as a general way forward !  At the moment there are two proposals on
the table.  You can't say `I will leave it to others to [alter the
spec]', because there is no specification that says you should do A6
rather than AAAA.

> against this.  It needs to be implemented and used.

I agree that we should assist with renumbering, reduce routing tables,
and make IPv6 more deployable.  But A6 does not help with this.  In
fact, requiring a complex protocol like A6 where AAAA is adequate will
*hinder* IPv6 deployment.

Just because A6 was introduced to help with renumbering DOES NOT mean
that it is a good thing for that purpose.  Nor does it mean that A6
opponents are somehow taking sides in some kind of ipngwg politics
about renumbering.  I couldn't care less about that politics, and if
ipngwg say we need easy renumbering, fine. [1]

But ipngwg should not define DNS protocols, dnsext should so so.
In this case we have an overcomplex protocol which allegedly exists to
meet some renumbering requirement, but which is in fact unnecessary.

[1] Actually, as a layman when it comes to IPv6, renumbering, etc., I
approve of making renumbering easy.  But I'm no expert in that field,
and I'll leave that to those who are.  Likewise, DNS protocol and
architecture should be done by the DNS experts.

Ian.

---

From: Ian Jackson <[email-masked]>
Date: Fri, 4 May 2001 15:13:34 +0100 (BST)

I'd like to ask a procedural question.  I'm not sure this is the right
place, but this thread will do since this is where the substantive
discussion is happening.  I looked again at 2026 but it wasn't much
help.

I think we are now approaching the time to use whatever the formal
procedure is to declare RFC2874 Historic.  Presumably this will
involve getting rough consensus in at least the dnsext wg [1], which I
think we might be close to.

[1] Some may argue that since 2874 was not really a dnsext document
but an ipngwg one, it can't be withdrawn by dnsext.  If this is true,
then it was probably out of scope for ipng, or at the very least, if
dnsext disagree with it then dnsext should be able to obsolete it and
require ipngwg to state their requirements so that the protocol design
can be done by dnsext.

But how should this be initiated ?  Should I write an I-D summarising
the discussions, with the aim of it eventually becoming an
Informational RFC which obsoletes 2874 ?  (That would be an IESG
standards action, I suppose, despite it being the publication of an
Informational document.)

Should we start work on polishing up AAAA (RFC1886) to move it to
Draft Standard ?  I'm not mistaken, am I, about there being at least
two interoperable implementations of AAAA and ip6.int ?

If we can't get consensus on AAAA going to Draft Standard, can we
polish it up a bit and publish it once more as Proposed Standard but
obsoleting 2874 ?

Are some, all, or none of these the right way to do it ?

Ian.

---

From: Jim Bound <[email-masked]>
Date: Fri, 4 May 2001 22:44:37 -0400 (EDT)

A6 is already in DNS implementations.  Its just a matter of using it. No
one can tell the market not to use it.  Or use it.  This is not an IETF
issue.  Sorry strike my comment.

thanks

/jim