[arin-ppml] Portable address space vs. IPv6 auto-numbering

Paul Vixie paul at vix.com
Thu Jun 12 10:16:50 EDT 2008

> > while i am not a member of RRG, if the question is drawn as clearly as
> > that, my position would be, forget about IPv4.  the internet will have
> > many more than 2^32 devices connected to it simultaneously within our
> > lifetimes, and i think we should preserve the option of not using NAT in
> > future generations.
> >
> > therefore IPv4's growth has a glass ceiling formed by its address size,
> > and any effort that's put into growing its routing table has a fixed
> > return.
> OK - quite a few people on the RRG agree with you on this.
> Here is a more nuanced version:  ...

i think that what quite a few people on RRG might be in agreement with is the
first qualified statement i made, "...forget about IPv4."  however, the
qualification is important: "if the question is drawn as clearly as that,"
which it sounds like it isn't.  furthermore, what i mean by "fixed return"
is that it's economically damned: the more effort we put into it the more
expensive that effort will turn out to have been.  i don't know if the RRG
folks are looking at this as an economics proposition but if not, there isn't
really any necessary relationship between what i said and what they might,
under different and/or synthetic circumstances, agree with.

i'm not just picking nits -- your "more nuanced version" does not represent
my view correctly, it is not a restatement of any position i've had nor of one
i can agree to.

> ...
> Many IETF folks have had unrealistic optimism about end-users wanting or
> needing IPv6 for over a decade.  While I know that IPv4 with NAT etc. falls
> a long way short of the ideal, I still think many IETF folks are
> unrealistically optimistic about IPv6 adoption in the next 10 years.  I
> think there are plenty of coping mechanisms for keeping IPv4 tolerable for
> most users in that time frame and probably beyond - and these will be
> cheaper and better for ISPs than trying to sell an IPv6-only service.

while on the one hand i completely disagree, the bigger issue is, you're just
saying what you think, here, whereas in your two previous articles you shared

> The transition mechanisms are not there.  The IPv6 Internet doesn't connect
> properly to the IPv4 Internet.  People like the IPv4 Internet because
> everyone is reachable via it.

these are plain facts and i agree.  (i wanted to agree to something here.)

as to optimism, jean camp showed some S curves in denver describing adoption
of technology, and while a lot of folks didn't understand them, they were well
argued and well reasoned, and they give *no* cause for optimism wrt IPv6.  so,
if provable pessimism about IPv6 were an argument in favour of prolonging the
lifetime of IPv4, you'd need look no further than elmore/camp/stephens:


alain durand's current plan is to native V6 to their customer edge and
backbone, and use native V6 to carry NAT'd V4, and thus get provide stack to
the comcast customer base.  apple and microsoft, as well as every IP-capable
device designed or manufactured in japan, as well as most f/l/oss software,
will all use native V6 if it's present.  there's a very real deployment
scenario involving islands of this kind of dual-stack, followed by address
space shortages and/or explosive routing table deaggregation, followed by
heightened, agitated capital investment in more dual-stack because it's a way
to avoid the worst pain of the shortages/explosions.

> I think a scalable IPv6 could be prepared, which sounds like heaven to many
> IETF people (though I still think 128 bits is 64 too long) - but the main
> population of end-users wouldn't care, since it is a different planet with
> almost none of their friends on it yet.

i think we're going to see IPv6 routing table bloat earlier than RRG's work
could possibly complete, and that that's the real race here, and that any time
spent prolonging IPv4's doddering old age with double- and triple-NAT is a
dangerous distraction.  the internet is not just the web, and we can't go on
building new kinds of applications if everything has to be some kind of NAT
or map-encap or ALG or proxy.  IPv4 is headed for end-of-life.  let's move on.

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