nanog mailing list archives

Re: [arin-ppml] NAT444 rumors (was Re: Looking for an IPv6 naysayer...)


From: Benson Schliesser <bensons () queuefull net>
Date: Tue, 22 Feb 2011 02:29:23 -0600


On Feb 21, 2011, at 10:16 PM, Chris Grundemann wrote:

On Mon, Feb 21, 2011 at 19:08, Dan Wing <dwing () cisco com> wrote:

Its title, filename, abstract, and introduction all say the problems
are specific to NAT444.  Which is untrue.

I just re-read the filename, abstract and introduction, and I disagree
that any of those say that the problems are specific to NAT444. They
all do state that these problems are present in NAT444, but not that
it's the only technology/scenario/configuration where you might find
them.

Let's at least agree that the text isn't precise.  I've had a large number of conversations in which relatively 
intelligent people advocated other (non-NAT444) scenarios involving CGN, built on the premise that NAT444 is broken and 
draft-donley-nat444-impacts is evidence.  Either the draft is perfectly clear and all of these people are stupid, or 
the draft is misleading (intentionally or unintentionally).

More importantly, I am unsure the point of this argument. Are you
trying to say that the items listed as broken in the draft are not
actually broken? Because in my experience they are. IMHO, the fact
that they are also broken in other (similar) scenarios is not evidence
that they are not broken in this one. On the contrary, this scenario
seems to be evidence to the brokenness in the others (until we get a
chance to test and document them all - are you volunteering? ;).

There seems to be a position, taken by others on these lists, that IPv6 is the only address family that matters.  
Interestingly, this position seems to be most pronounced from people not involved in operating production networks.  
But, regardless, if I were to accept this position then I might also agree that it doesn't matter whether or not 
draft-donley-nat444-impacts is misleading.

On the contrary: While I emphatically agree that IPv6 is the path forward, I don't accept the notion that IPv4 no 
longer matters.  IPv4 is the present-day Internet, and IPv4 connectivity is demanded by present-day paying customers - 
you don't burn the bridge until *after* you've crossed it.  Further, given that IPv4 does matter yet has an exhausted 
address supply, there exists a need for IPv4 address sharing technology.  Fundamentally, this means that we need to 
discuss and engineer the best possible address sharing technology.  It may never be as good as native end-to-end IPv6, 
but sub-optimal is not the same thing as "broken" as others have claimed, and sub-optimal might be acceptable if it's 
the only alternative.

Of course, we can also rely on an IPv4 address market to avoid NAT in the more sensitive situations (i.e. situations 
with more sensitive users).  But that's a different conversation.

Cheers,
-Benson





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