[ppml] IPv4 is not going away was: IPv4 "Up For Grabs" proposal

[michael.dillon at bt.com]

> ...v4 
> is already built into infrastructure pieces that are not 
> likely to see communications upgrades for 10 to 20 years.  I 
> routinely speak to aviation industry leaders on this and I 
> generally place v4 end of life somewhere from 25 to 40 years out.

I agree with this timeline. I think that anyone who cares to dig can
find numerous examples in industry where IPv4 is similarily embedded
into infrastructure. The trick is to look at non-Internet and
non-corporate-LAN applications. There are vast quantities of embedded
systems based on Intel 8080 architecture chips (microcontrollers)
running IPv4 which cannot be upgraded, only retired.

When we talk about the end of global IPv4 address supply, we are most
certainly not talking about the end of IPv4. And when we speak of
beginning to deploy IPv6 on a systematic global basis, we are not
talking about replacing IPv4.

I expect that we will see 3-4 years of IPv6 deployment, followed by 10
years or so in which IPv4 usage steadily reduces and IPv6 steadily
rises. Then in about 14-15 years we will begin a period of consolidation
in which there is an effort to retire IPv4 on the public Internet and in
corporate/enterprise networks. Give this another 10 years, which means
that in about 25 years, IPv4 will be considered end-of-life. At that
point, general purpose networking gear will cease to support IPv4,
however it is possible that new IPv4 devices will continue to be built
for special uses. Even today, it is not hard for an undergraduate
student to build their own IPv4 router using off-the-shelf parts and
open-source software. Even ASICs are available off-the-shelf in the form
of FPGAs and one can expect that in 25 years this type of thing becomes
even easier and cheaper. So IPv4 may linger on for a few generations
hidden inside MP3 player headsets and heel computers (inside your
running shoes) and concert posters.

This issues before us today, are how to keep IPv4 going even though we
are getting close to exhausting the global IPv4 address supply, and how
to get IPv6 deployment moving faster so that we can reduce the pressure
on the global IPv4 address supply. If we do this right, especially on
the IPv6 deployment side, we may be able to stave off complete
exhaustion of IPv4 addresses long enough to get into the time period
where IPv4 usage starts to shrink. This is anywhere from 3 to 5 years
from now. If we do nothing, then in 3 years or less, we hit a brick
wall. If we do the right things, then in 5 years things get very, very
tight, but we manage to supply everybody's IPv4 needs (not wants) up to
the point where people start returning addresses for reuse.

That's why the discussions are not just about speeding IPv6 and scraping
up the last few IPv4 addresses from legacy holders, but also about
putting a reclamation system in place with the right policies and the
right processes.

--Michael Dillon