[arin-ppml] IPv4 Depletion as an ARIN policy concern

michael.dillon at bt.com michael.dillon at bt.com
Mon Nov 2 12:05:25 EST 2009

> There is also the very real possibility that we never get to 
> ipv6 and ipv4 simply becomes a closed system with only 4 
> billion "chips" into the big game (at least until some 
> technology comes along to supercede everything).

No way. There are too many lessons learned from other

> In the 30's 
> New York City started requiring licenses for taxi's to pick 
> up fares.  70 years later, the same amount of licenses 
> existed (they did auction some more off in the last few 
> years).  The system simply adjusted to that circumstances.  
> There are other forms of mass transit in that city but the 
> very specific need  of point-to-point pickup (if you're 
> standing on a street corner) was only doable through  those 
> licensed taxis.  

That's one of the lessons learned.

By the way, in London England, the barrier wasn't badges, but
"The Knowledge", a tough test that requires the potential taxi
driver to know their way through every part of the city, most
of which is still a warren of medieval villages connected by
narrow twisting medieval roads. In order to get from point A
to point B, the potential taxi driver needs to learn which
alleyways to use as shortcuts, where to make U-turns to avoid
congestion, and which times of day the various routes will work.
Not to mention all the street names which can be repeated
numerous times in different parts of the city. Also oddities
like Cannon Street Road which is nowhere near Cannon Street.

The solution that was developed in London was the mini-cab. This
is just an ordinary car that you can hire to travel point-to-point
except that they cannot pick up fares in the street, because that
is illegal without a licence. But lots of them do it anyway and
in addition, people will mobile phones hang around near bars
whispering "taxi" to anyone who walks by. If someone wants a taxi
they call up on the mobile and the driver who was waiting around
the corner shows up. There were so many of these illegal mini-cabs
with drivers who often knew little English, and sometimes even had
no driving licence, they outnumbered the legals. I remember my
first day in London at the new job 10 years ago when the mini-cab
driver was trying to look at a map while driving down busy roads.
I had to grab the map from him, figure out where I was going and 
give him directions.

In the end, the government decided to licence the mini-cabs in
order to get the worst drivers off the road, perhaps even into jail.

What's the IP addressing analogy to London?

NAT and middleboxes. Where there is demand for a service, 
people will figure out a way to do it even if the designers
and architects don't feel it is necessary. Don't worry about
IPv6 and IPv4 coexistence because it will work itself out.
It's not necessary to know how this will happen up front, nor
is it necessary to impose some well-meaning solution today.

There is no question about whether or not IPv6 will happen.
It has already happened, and is now ramping up growth.

--Michael Dillon


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