Subject: Re: myth of the great transition (was US Defense Department forma lly adopts IPv6)

From: "J. Noel Chiappa" <[email-masked]>
Date: Fri, 20 Jun 2003 07:48:31 -0400

> From: Eric Rescorla <[email-masked]>

    > (2) NAT solves at least some of those problems, at some
    >    cost (say Cn), both financial and operational and
    >    that solution has benefit Bn.

    > (3) The fact that a large number of people have chosen
    >     to use NAT is a strong argument that B>C.

Ah, I think your model has a fatal oversimplification here - but it's one I'm
glad you made, since it has given me a clue to a deeper understanding of why
NAT's are doing so well. Here goes...

The problem with your analysis is that there's no single value of C and B for
everyone; those numbers depend on what you're trying to do. So for *some*
people, B>C (we'll call this group NAT-Users, or N-U for short) - but for
*other* people, C>B (and we'll call them NAT-Avoiders, or N-A).

We've heard from a number of the latter group - people who want to run voice
(not over tunnels), people who want to run IPSEC (not over tunnels), etc.
However...

The interesting point that I get from thinking about this is that we need to
think about the size of the two groups - and in particular, how large the N-U
group is likely to be down the line.

That group has no reason to deploy any new technology - what they have
already works fine for them. So if there is a very large population of N-U,
especially if they are a big enough group to be a majority of the Internet
user base, then I think we're going to have to continue to interoperate with
those people.

That means that i) NAT+v4 is here to stay, permanently, as the
packet-forwarding substrate on which we have to live, and ii) many
"solutions" to the "NAT problem" have a badly faulty key premise - which is
that the solution will fix IPv4's problems by replacing it.

The notion of a system with a single, globally unique namespace at the lowest
level is a really nice one, one we had for a while - and *one we think we can
reclaim*. I now think we've been deluding ourselves; that past (like so many
others, e.g. the one where we didn't have spam) is gone for good.

I think the IETF needs to face that painful reality, or become increasingly
irrelevant.

	Noel

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From: Keith Moore <[email-masked]>
Date: Fri, 20 Jun 2003 10:54:20 -0400

> "solutions" to the "NAT problem" have a badly faulty key premise -
> which is that the solution will fix IPv4's problems by replacing it.

almost agree.  NAT is here to stay on v4, and apps that work fine with
NAT+v4 will continue to use NAT+v4, at least for the near to medium
term.   nor is there likely to be a replacement for NAT in v4, because
there's no way to get any more addresses out of 32 bits.

so I don't see us replacing NAT in v4. but I do see us building another
network that uses the same layer 1-2 links as the IPv4+NAT network but
also provides an alternate layer 3.

the reason I point out the flaws with NAT is not that I think we can get
rid of them in v4. it's because some people are still of the belief that
NATs are mostly harmless and that we should not only permit them
into v6, but extend our architecture to embrace them.  that's simply
insane.

Keith

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From: Vernon Schryver <[email-masked]>
Date: Fri, 20 Jun 2003 09:36:49 -0600 (MDT)

> From: Keith Moore <[email-masked]>

> ...

The current combatants seemed to fail to notice a long time ago when
those who started this thread by claiming NAT boxes are clearly good
and desirable things were convinced, or more likely, went elsewhere
to peddle their views.

Vernon Schryver    [email-masked]

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From: S Woodside <[email-masked]>
Date: Fri, 20 Jun 2003 14:16:38 -0400

> user base, then I think we're going to have to continue to 

A lot of these people would like to be voice users, which you grouped 
as NAPT Avoiders. They might use v6, if there were a dead-easy box that 
would make it work with v6, and the voice apps upgraded to v6, and the 
OS supports v6.

simon

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From: S Woodside <[email-masked]>
Date: Fri, 20 Jun 2003 14:16:38 -0400

simon