Subject: Re: breaking the IP model (or not)

From: Pyda Srisuresh <[email-masked]>
Date: Wed, 12 Apr 2000 17:02:28 -0700 (PDT)

--- Keith Moore <[email-masked]> wrote:
> > I'm being a bit extreme but the point is that just because something is 
> > architecturally bad doesn't mean you shouldn't do it, since these days it 
> > takes us years to make any architectural enhancements.
> 
> perhaps architectural impurity alone shouldn't keep you from doing 
> something, but the fact that something violates fundamental design 
> assumptions should cause you to do some analysis and hard thinking
> about the likely consequences of using them.  and if you are in the
> business of selling boxes that violate the design assumptions you 
> shouldn't misrepresent these to your customers.
> 
> most of these hacks can be employed in ways that are mostly harmless,
> but knowing when they are harmless and when they will cause harm
> can be quite difficult.  NATs seemed mostly harmless when they were 
> first deployed; now they're a huge problem.
                                ^^^^^^^^^^^^

Hmm... Depends on one's perspective. Do not underestimate the
timeliness of a solution. Timeliness is operational reality.

It could have been catastrphic had we not had a timely solution 
with no addresses to issue. NAT is the reason we have had this much
time to work on IPng.
 
> Keith

regards,
suresh

=====

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From: Keith Moore <[email-masked]>
Date: Wed, 12 Apr 2000 22:17:24 -0400

> timeliness of a solution. Timeliness is operational reality.

I'm very much aware of this.  timelinesss is what gives you
(or denies you) the opportunity to deploy a new technology.
but just because something is timely (in the sense that
there is an opportunity to deploy it) does not mean that 
deploying it leaves the world in a better place.
 
> with no addresses to issue. NAT is the reason we have had this much

it's not at all clear whether NAT provided additional time for
IPng development or whether such time was really needed.  IPv6 was 
largely developed before NAT enjoyed significant deployment, and 
arguably NAT has delayed adoption of IPv6.  and because of the NAT 
deployment it is now somewhat "untimely" to deploy applications like 
IP telephony.  whereas if IPv6 had been adopted a bit earlier 
(because NAT had not filled the vacuum, so to speak) IP telephony 
would work just fine with it.

of course, IPv6 might have moved along slowly even without NAT.
but it would probably have moved faster had NATs not existed.

best thing I can say about NAT is that it motivated me to work on 6to4.

Keith

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From: Peter Deutsch <[email-masked]>
Date: Wed, 12 Apr 2000 08:55:13 -0400

g'day,

> deploying it leaves the world in a better place.

I'm reminded of that scene in "Butch Cassiddy and the Sundance Kid"
where Paul Newman and Robert Redford have been cornered at the top of
the cliff by the pursuing posse ("who *are* thoe guys?") There is no way
out except the 100 foot drop into the raging river below. Newman is
trying to encourage Redford to jump, with the idea that they can then
swim to safety. Redford just keeps saying no, finally confessing that he
can't swim and is afraid of drowning. Newman laughs, and points out that
he should stop worrying, as the fall will probably kill him.

The relevance, for those who miss my obscure references, is that we were
faced with a 100 foot fall into a river, and we made the jump to NATs
and address translation. Sure, it was a horrible thing to do, but we're
still alive and dog paddling to the next crisis, which may well be the
horrors you can forsee awaiting in the raging rapids of IP address
renaming.

This is, believe it or not, progress. Sure, in the ideal world we'd have
found a row boat when we got here, or even stairs down the ciff, but
where we are now is still better than the alternatives we wee facing
before. And this may not be the engineering you want to see us do, but
to quoe the old farmer, "if we wanted to be there, we wouldn't be
starting from here"...

Keith, give it up, you're beating a dead horse. Accept that you're not
going to get perfection in the real world, nor convince those of us who
live the real world that perfection tomorrow is preferable to working
today. I would *love* to see you document the known problems with
paddling in this direction, but please stop trying to pretend the
horrors of this violation of the IP model means we must ban its use. 
Given your choice, we'd still be up at the top of the cliff, with a
noose around our necks...

					- peterd

-- 
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Peter Deutsch                               work email: 
[email-masked]
Technical Leader
Content Services Business Unit                 private:
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Cisco Systems                                     or  : [email-masked]

             Alcohol and calculus don't mix. Never drink and derive.
--------------------------------------------------------------------------------

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From: [email-masked]
Date: Wed, 12 Apr 2000 23:55:16 -0400

> timeliness of a solution. Timeliness is operational reality.

I think Keith meant "huge problem" in the same sense that a kidney
dialysis machine is a huge problem.  They keep the patient alive,
but never in the greatest of health or comfort.

				Valdis Kletnieks
				Operating Systems Analyst
				Virginia Tech

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From: Keith Moore <[email-masked]>
Date: Thu, 13 Apr 2000 07:22:14 -0400

Peter,

you are missing the point, and your arguments are unpersuasive.

Keith