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Re: NAT Not Needed To Make Renumbering Easy

2009-10-27 16:50:29
Greg,

On 2009-10-28 05:42, Greg Daley wrote:
Hi Dean, 

I appreciate that this is a realistic challenge for one of the key
users of the technology.

As a key user of the technology.  Why didn't we learn about this 
earlier in the process?  

Well, the military interest in damage-proof tactical networks hasn't
been a secret over the last 5 years or more.  However, "tactical networks"
only gets 90 hits on the IETF search button, which does seem
surprising. Similarly for "network centric operations", the other
euphemism for battlefield networks.

Perhaps if we did, we could have supplied
a solution which doesn't suck as badly as NAT.

"The purpose of the MANET working group is to standardize IP routing
protocol functionality suitable for wireless routing application within
both static and dynamic topologies with increased dynamics due to node
motion or other factors."

"The main purpose of the AUTOCONF WG is to describe the addressing model
for ad hoc networks and how nodes in these networks configure their
addresses."

I think the IETF has taken the attitude that the only non-sucking approaches
involve dynamic addressing and routing. And it's quite hard, which is why
MANET and AUTOCONF aren't quite done yet...

    Brian


I am quite interested to know your opinion. Was it because we weren't
looking to meet the customer's need, a breakdown in requirements
specification,
or something else?

Sincerely,

Greg 

-----Original Message-----
From: ietf-bounces(_at_)ietf(_dot_)org 
[mailto:ietf-bounces(_at_)ietf(_dot_)org] On 
Behalf Of Dean Willis
Sent: Wednesday, 28 October 2009 3:02 AM
To: Sabahattin Gucukoglu
Cc: ietf(_at_)ietf(_dot_)org
Subject: Re: NAT Not Needed To Make Renumbering Easy


On Oct 25, 2009, at 10:49 AM, Sabahattin Gucukoglu wrote:

Not in the IPv6 address space, anyway.  And if it is, there's  
something wrong and we should put it right.

Just been reading IAB's commentary on IPv6 NAT.  It seems 
to me that  
we are perpetuating the worst technology in existence *simply* for  
one feature, network mobility, that is better served by proposing  
new techniques and technologies and, in particular: we need 
a simple  
way to express host relationships inside an organisation that is  
independent of external homing.  I refuse to suffer because of NAT  
any longer and don't want to accommodate those that prefer it.  If  
IPv6 does ever get wide enough deployment, and I truly hope 
it does,  
I might just *give up* things to accommodate the trouble-free life  
that is no NAT.

What do we have right now, first?

As I understand it, the folks really pushing for IPv6 NAT are 
from the  
US department of defense.

Let's consider a battlefield operation.


We have a hierarchical organizational structure. At any given level,  
there are a collection of numbered boxes. For example, consider   
infantry companies, of which there might be 8 or so in an infantry  
battalion.

Company A has a bunch of networked boxes, A1, A2, A3, and so on.  
Companies B, C, D, and so on have the like.

A1 is configured exactly like B1, C1, D1, and so on, with the 
same IP  
addresses, passwords, default routes, everything. The inter-layer  
boxes use NAT to make everything work, even that we have 
re-used local  
addresses at every level of the hierarchy.

The battalion command post may also have some spare #1 boxes, #2  
boxes, etc.

Assume artillery falls on the command posts for Company A and 
Company  
B and blows up some of their boxes. Recovery may necessitate 
combining  
the networked boxes and command structures of both companies.

So, while getting shot at, the network techs are busy running boxes  
back and forth. Let's make a simple case: Boxes A2, A5, and A7 got  
hit, so they're replaced by B2, B5, and B7. B3 and B4 are also hit,  
bringing the B network down completely  Meanwhile, the 
battalion guys  
are shipping out spare #2, #3, #4, #5, and #7 boxes to company B.

The B-boxes need to work instantly when plugged-in as 
replacements for  
A boxes. There's no time for manual reconfiguration, probably 
no time  
for dynamic topology discovery, or anything else. The techs on the  
ground don't have the passwords, equipment, or know-how to 
reconfigure  
the boxes anyhow -- mostly, they just know to plug wire 1-4 
into box 1  
port 5. And the same goes when the spare boxes from the battalion  
level arrive at company B -- they have to plug in and work instantly  
without renumbering anything.

NAT is the glue that makes all this work with minimal 
reconfiguration,  
and isolates what manual reconfiguration is needed to a specific set  
of boxes at interconnect points, for which standardized 
procedures can  
be developed that allow topology to be reconfigured on demand under  
very difficult circumstances.

Keep in mind that all this stuff also has to be wrapped in military- 
grade crypto, resist Tempest-style interception, remote radio data  
insertion attacks, jamming, and sorts of protocol attacks, so 
"brutal  
simplicity" is the by-word of the day. We can't have a network fall  
apart just because some enemy sapper managed to clamp a rogue 
Linksys  
access point with a DHCP server onto a wire somewhere ...

So, if IP applications and protocols worked entirely differently, we  
could get away without NAT in IPv6. We'd kind of hoped that things  
like Bonjour and multicast service discovery and P2P would have  
matured fast enough to plug the gap, but so far they haven't 
been seen  
as adequate (and I'm not an expert on "why not"). Plus, the  
military  
mindset is understandably reluctant to change things that work. And  
since NAT made all this stuff work for IPv4, they're planning to use  
it for IPv6 too.

--
Dean

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