[arin-ppml] IPv4 is depleted today - unrealistic statements about IPv6 inevitability

Paul Vixie vixie at isc.org
Sat Aug 30 12:46:15 EDT 2008

rw at firstpr.com.au (Robin Whittle) writes:

> I think this is completely unrealistic:

i think it's only mostly unrealistic :-).

> IPv6 isn't much use to anyone right now, because almost no-one else
> is using it

there's a significant last-mover advantage, and so the people who want to
finish the transition with the most money, are hanging back and letting
everybody else go first.  this is "the network effect" in action.  at PAIX
when we opened a new site nobody wanted to be the first one to connect to
the peering switch, but folks were anxiously desirous to get the tenth port.

that doesn't mean IPv6 is a bad idea any more than new peering points are
a bad idea.  it just means uptake is slow at first on stuff like this, and
that early adopters have to be insensitive to their in-year revenue and
expense prospects.  IPv6 works fine for the early adopters who use it to
talk to each other and who are getting their equipment and training done
NOW so that if it actually takes off in a big way they won't be in a hurry
later.  it's well understood that investment in IPv6 will probably not yield 
much same-year revenue, and that the largest part of the "endpoint base"
will not move until that changes.

when other networks can't get new IPv4 or can't deaggregate the IPv4 they
bought off of e-bay fast enough because the other, other networks can't
grow their routing tables fast enough, then those other networks are going
to start doing their growth some other way.  they won't stop growing.  GIH
seems to think that the "other way" this growth will happen is going to be
NAT and while i agree that there will be an uptick i cannot think that this
will be all that happens.

many of you here won't need IPv6 because you've run out of space.  you will
need IPv6 because other networks have run out of space, and because new
deployments will have no choice.  but you don't have to take my word for it;
you can wait for hard evidence and then do a bunch of in-year hurry-up
unbudgeted upgrades.  i think that approach is a little bit silly, since the
actual costs of running dual-stack, at least near your edge or in your labs,
is not high enough to be worth avoiding.  even if you have to tunnel at
first because your upstreams and/or peers aren't as visionary as yourself.

speaking of vision, here are the competing ones as i see them.  on one hand
we've got a massively deaggregated IPv4-only core with the density of pure
neutronium and only the largest carriers able to handle the route churn and
FIB storage, and where the market value of one more /24 is set by the cost
of trying to find someone who will route it for you, and there are harsh
pressures on old PI, and there's more or less no new PI, and there will be
no new entrants into the IPv4 core routing market.  the rest of us will be
paying high dollars for edge PA and using NAT universally.  all new apps will
either not depend on end-to-end or they will fail, so things like VoIP will
have to be carrier-side and most new apps will ride on TCP/80.

on the other hand we've got a brief unpleasant period like described above
before enough other networks add native IPv6 to make it worthwhile for late
adopters to finally add native IPv6, at which point new apps have a choice
of "IPv6 native, or IPv4 NAT" and new entrants to the core routing arena
have that choice and while it's risky some folks will make it work somehow.
pressure against PI will remain about the same as it is now.  NAT will
gradually shrink down to places where its security features are worthwhile,
or where there's just no good enough reason to tear it out and go native.

i don't merely like the second vision better.  i am the parent of teenagers
i have studied history and am sure that if new generations of humans and
their corporations are told that they will have to live out their lives
according to the values and compromises of their forebears and that their
opporunities must all be shackled by tithes to existing landowners, then
they WILL find another way.
Paul Vixie

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