Subject: Re: IP network address assignments/allocations information?

From: "J. Noel Chiappa" <[email-masked]>
Date: Wed, 8 Dec 1999 13:58:43 -0500

> From: Ed Gerck <[email-masked]>

    > maybe this is what the market wants -- a multiple-protocol Internet,
    > where tools for IPv4/IPv6 interoperation will be needed ... and valued.

This relates to an approach that seems more fruitful, to me - let's try and
figure out things that sidestep this incredibly divisive, upsetting and
fundamentally unproductive argument, and try and find useful things we can do
to make things work better.

    > Which can, undoubtably, be put in a sound theoretical framework for
    > NATs, in network topology. NATs do not have to be a hack.

Well, the fundamental architectural premise of NAT's *as we know them today* -
that there are no globally unique names at the internetwork level - is one
which is inherently problematic (long architectural rant explaining why
omitted). So I don't think that the classic NAT model is a good idea,
long-term.

However, I think it's a bit of a logical fault to think that the only options
are i) IPv6 and ii) NAT's. That's like saying that if my dog's not in my
office, he must be on Mars - there are other alternatives! This is especially
true in the long run; we may be stuck with NAT in the very short term, but
in the longer term we can explore other alternatives.

    > NATs ... seem to have been discovered before being modeled, that is
    > all.

Umm, not quite, IIRC. Papers by Paul Tsuchiya and Van Jacobsen discussed the
concept a long time before any were commercially available.

	Noel

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From: Yakov Rekhter <[email-masked]>
Date: Wed, 08 Dec 1999 11:19:18 -0800

Noel,

> omitted). So I don't think that the classic NAT model is a good idea,

I would say that the fundamental architectural premise of NATs is that
globally unique names at the internetwork layer are not carried in the
network layer header. This is not to say that such names don't exist -
just that they aren't in the IP header.

Yakov.

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From: Yakov Rekhter <[email-masked]>
Date: Wed, 08 Dec 1999 11:19:18 -0800

Noel,

Yakov.

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From: Ed Gerck <[email-masked]>
Date: Wed, 08 Dec 1999 13:00:49 -0800

> to make things work better.

I suggest we first revisit the concept of collaboration itself.  IMO, collaboration
can no longer be understood as similar agents doing similar things at the same
time but as different agents doing different things at different times, for the same
objective.  Then, we can build protocols that will support this notion of
collaboration, where diversity is not ironed-out by hypotheses but actually
*valued* and used in interoperation.

> omitted).

That fundamental premise is trivially true (so, no need for rant ;-) ). However,
this is not what I was mentioning, as I think we are talking about something
even more fundamental.  A topology is simply a division of space, simply
speaking.

In these terms, data is no longer an absolute quantity.  Indeed, when thinking
about data in communication processes (networks) it has so far seemed
possible and undisputed to regard data as “information in numerical form
that can be digitally transmitted or processed”, and whose total quantity is
preserved when a system is divided into sub-systems or when different data
from different sources are compared. Actually, this picture is wrong to a large
extent and NATs are the living proof of it -- there are natural laws also in
cyberspace.

The very concept of data needs thus to revisited. Suppose we define data as the
*difference* D2 - D1 that can be measured between two states of data systems.
Then, it can be shown that this difference can be measured by means of a
communication process only if 1 and 2 are two states of the same closed system.
When they are not, NATs are a solution to create a third-system, a common
reference between 1 and 2.  Which can be conceptual or physical or both, but is
needed. In this formalism, a numerical value for data can be defined even though
1 and 2 may belong to different systems, or even though the data systems may be
open --  the only restriction is to have a common reference.

This is the mind-picture we need to overcome IMO -- that data is absolute. It is
not and this answer implies that we need to find "data laws" in order to describe
exchanges of data much in the same way as we needed to develop Thermodynamic
laws in order to describe exchanges of energy (itself, not an absolute concept,
either).

> So I don't think that the classic NAT model is a good idea, long-term.

I suggest we don't yet have a "NAT model", in engineering sense, where
a model fits in a larger model and so on. All we have is a "NAT hack".
And, I agree that the NAT hack is not a good idea, even mid-term.

> are i) IPv6 and ii) NAT's.

Yes, especially NATs as they are -- somewhat born out of need, not so
much design.

> concept a long time before any were commercially available.

Discussed the concept, as one may argue that telegraph systems also did when
they needed to define telegraph codes in each station, so that different
"John  Smith" could respectively get their proper messages even though
they all "shared" the same name.

What I meant is not this. What I meant is an ab initio model of  data in
network systems, where NATs are one instance of a third-system that is
*needed* in order to provide a common but quite arbitrary reference for
"measuring" data between different systems, without requiring any
change to them.  In such a formalism, there are data levels NATs can handle
and others it cannot, try as one may  -- which needs to be recognized and
provided for each case, by yet other objects.

Cheers,

Ed Gerck

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From: Ed Gerck <[email-masked]>
Date: Wed, 08 Dec 1999 13:00:49 -0800

Cheers,

Ed Gerck

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From: Lloyd Wood <[email-masked]>
Date: Thu, 9 Dec 1999 00:06:08 +0000 (GMT)

> communication process only if 1 and 2 are two states of the same closed system.

Since not all system state is communicated and any communication is a 
near-minimum abstraction of system state, this idea is a non-starter.

> laws in order to describe exchanges of energy (itself, not an absolute concept,

Absolute zero always seemed pretty damn absolute to me.

Taking your energy analogy further and better, NATs (and firewalls)  
are the protocol equivalent of Maxwell's demons; unfeasible in
practice without considerable sources of computation and energy as
inputs (read: overhead and administration) and with results that are
extremely theoretically unsatisfactory.

> provided for each case, by yet other objects.

For every type of molecule or energy level you might encounter, you
have to add another demon.

L.

this discussion is going round and round in circles of hell.

<[email-masked]>PGP<http://www.ee.surrey.ac.uk/Personal/L.Wood/>

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From: Lloyd Wood <[email-masked]>
Date: Thu, 9 Dec 1999 00:06:08 +0000 (GMT)

L.

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From: Ed Gerck <[email-masked]>
Date: Wed, 08 Dec 1999 19:04:47 -0800

> near-minimum abstraction of system state, this idea is a non-starter.

I understand your doubts; this is a new approach.  But communication is
not a "near-minimum abstraction of system state" -- whatever you mean
to communicate by that ;-)  The very failure of your communication in that
phrase (and, my very failure to communicate to you in my phrase) exemplifies
my phrase, however.

> Absolute zero always seemed pretty damn absolute to me.

There is no absolute value of energy associated with absolute zero
temperature -- if that is what you mean.  There are many quantities
which are not absolute, distance is another example (besides
energy and data). Phase is another.  But there are absolute
quantitites, of course.

> are the protocol equivalent of Maxwell's demons;

No. This analogy is not correct. Note also that Maxwell's demon has
been proved not to be possible, even theoretically.

> have to add another demon.

There are no demons here. If you agree that data is not absolute then
my explanation follows.  If you do not agree, then please tell me if
"2=2" is true or false -- it is a simple expression, a simple data point
given by "2=2".  But your answer, whatever it is, will prove it is
not absolute.

What is the significance of this?  Not to make matters more complicated but
to recognize that NATs are not demons ;-)

In other words,  either we have *one* closed data system (IPv4, IPv6, etc.) where
we can easily define data values by difference in data states (where an
arbitrary value of zero is assigned to a system-wide reference state),  or
we have *many* systems where we need NATs to provide reference states
between different systems in order to communicate between them.

Since IPv6 defines a larger system, it can encompass a series of different
IPv4 systems linked by NATs. However, since we *do* expect to encounter
IPv4 systems, even if IPv6 is extremely sucessful (say, takes over 80% of
the universe), then it follows that we will always need NATs to provide a
common reference between different systems.  Thus, it is worthwhile IMO
to model them and use them well, not demonize them :-)))

Cheers,

Ed Gerck

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From: Ed Gerck <[email-masked]>
Date: Wed, 08 Dec 1999 19:04:47 -0800

Cheers,

Ed Gerck