Subject: Re: [midcom] WG scope/deliverables

From: Joe Touch <[email-masked]>
Date: Wed, 31 Jan 2001 22:27:43 -0800

Ed Gerck wrote:
> 
> Keith Moore wrote:
> 
> > I expressed an opinion that this group should confine itself to addressing
> > short-term goals rather than trying to make NATs a part of the Internet
> > architecture.
> 
> NATs are already part of the Internet, and gaining share.

An alternate perspective is that the Internet continues
to (mostly) work despite the presence of NATs.

It is a paradox to begin one standard by selectively omitting
current standards (e.g., RFC1122). 

Joe

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From: Jon Crowcroft <[email-masked]>
Date: Thu, 01 Feb 2001 08:27:22 +0000

NATs are very useful sensible local optimisation devices to remove the
need for a number of other more complicated solutions - most of the
more complicated solutions are architectural and internetworking
solutions which NAT are not

address translation, as part of a set of techniques (address
aggregation, filtering, dynamic address allocation and lease/lifetime
control, address scoping, whether for unicast or multicast)
should be part of the midcom discussion

consideration of any protocol for
global coordination of address translation (e.g. so you can do 2 way
or n-way natting, leads to the conclusion that perhaps other
techniques (e.g. ipv6) are easier or actually no different (pace,
yakov:-) in terms of funcitonality (e.g. a distribution and
synchronisation protocol

why i keep mentioning GSE is that it does _partial_ NAT, which is
dfefinitily worth pursuing imho

In message <[email-masked]>, Ed Gerck typed:

 >>> I said this because I've looked at the problem quite extensively.
 >>> The more I have done so, the more have concluded that there's no way
 >>> to restore the valuable functionality that NATs have removed from the
 >>> Internet without providing another global address space, and that it's
 >>> much more efficient and less painful to embellish the NATs to become
 >>> IPv6 routers than it is to embellish both the NATs and applications to
 >>> support a segmented address space.
 >>
 >>You miss at least one other possibility.  If it is possible to develop
 >>an addressing scheme that works in a heterogeneous network, then
 >>we can have point-to-point functionality across system borders and
 >>do not require a homogeneous address space to do so.   Now, if you
 >>look into the science of Thermodynamics (for example) you will see that
 >>this involves a meta-problem that was already solved two centuries ago.
 >>
 >>NATs are a consequence of a choice rather than makers of a choice.
 >>The choice is to use heterogeneous networks. I contend that the reasons
 >>for this choice can be found in Nature -- for example, to adapt to local needs
 >>without imposing more expensive non-local changes.  This is not an Internet
 >>phenomenon, it is IMO the reflection of a more general principle.
 >>
 >>BTW, I agree with Noel's solution that a NAT-haters list might be in order.
 >>Maybe you could call it NAT-not list, to avoid the "hate".  Meanwhile, the
 >>rest of the world would continue to pursue ways to deal with the real-world
 >>needs answered by NATs (and things to come).
 >>
 >>Cheers,
 >>
 >>Ed Gerck
 >>
 >>

 cheers

   jon

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From: Ed Gerck <[email-masked]>
Date: Wed, 31 Jan 2001 15:05:34 -0800

Cheers,

Ed Gerck

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From: Lloyd Wood <[email-masked]>
Date: Thu, 1 Feb 2001 15:53:01 +0000 (GMT)

> this involves a meta-problem that was already solved two centuries ago.

Explain.

> The choice is to use heterogeneous networks.

NATs fake a homogeneous address space for disjoint/overlapping
*homogeneous networks*. You just layer IP over the top of the
heterogeneous networks - so we already have that addressing scheme you
want.

NATs are primarily a consequence of heterogeneous administration with
short-term local-optimisation goals that dictate use of homogeneous
network technology. (Address space shortages are also a result of
heterogeneous administration of a homogeneous and limited resource. As
are most things.)

Considered use of truly heterogeneous networks does not offer the
local optimisation NATs do (more translation, gateway maintenance),
and is rejected.

> I contend that the reasons for this choice can be found in Nature

well, yes. everything can be found in nature.

> -- for example, to adapt to local needs

Oh, right. Since we're waffling;

http://pespmc1.vub.ac.be/SUBOPTIM.html

and Gleick's 'Faster' (and Vinge's 'Deepness in the Sky', for that
matter) make some interesting statements and predictions about the
system-wide dangers of local optimisations. The zeroth law of
thermodynamics does not, IMO; entropy analogies can be highly
misleading.

It's useful to reflect on why we should be designing protocols with a
lot of overhead, redundancy, and slack in them. Contrast the success,
adaptability, longevity and utility of the ever-so-slack http with
that of the bit-efficient gopher. The lack of slack in the ATM header.
Or the slack in the GSM control channel that led almost by accident to
SMS.

If there's no slack, there's no serendipity, no escaping the local
minimum by subverting it. 

That doesn't have much to do with anything other than the work
required to handle the protocol reliably in NAT, though.

L.

IETF: optimising everything into a dead-end local minimum since 1986.

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

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From: Greg Minshall <[email-masked]>
Date: Thu, 01 Feb 2001 10:18:06 -0800

from some of the discussion, esp. yesterday, i had thoughts of deriving an 
anti-NAT polemic and posting it.  i planned on mentioning all of the other 
brain-dead, obsolete technologies "we" (IP) had in the past ignored, and how 
we had triumphed while they had died off.

i was thinking of things like IBM mainframes, BSC, SDLC, and ultimately got 
around to thinking of things "in our community" such as UUCP over asynch 
(mostly) phone lines, etc.

but as i thought of it, i realized that what "we" successfully  ignored in the 
past were things that had little use (the ISO acronym popped up in my mind).

things that were heavily used, we somehow brought into the fold and, in some 
sense, stepped on their shoulders on our way to "the world of greater 
connectivity".

the examples are numerous, and happened in different ways.  "we" invented ways 
of interconnecting (at least at the level of e-mail, the killer app of the 
80s) with IBM mainframes, VMS boxes, etc.

we ran IP over BSC and SDLC.

we invented MX records, as well as bizarre addressing formats (!%.etc.), to 
interconnect between the SMTP world and the UUCP world.

i guess if i think anything about all that, it is that if NATs are ubiquitous, 
we should figure out how to deal with them.  and, that (hopefully), we will 
achieve the "greater interconnectivity" on top of, and to some extent in spite 
of NATs.

cheers,  Greg Minshall

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From: Dave Crocker <[email-masked]>
Date: Thu, 01 Feb 2001 10:05:39 -0800

At 03:05 PM 1/31/2001 -0800, Ed Gerck wrote:
>do not require a homogeneous address space to do so.

There is roughly 30 years of experience in this realm that suggests otherwise.

The difference between theory and practise is practise.

If you wish to formulate a detailed technical specification, and subject it 
to community review and testing, perhaps you will indeed show show us an 
approach that will work.  Until then, your suggestion is just an untested 
theory.

d/