The Department of Work and Pensions, UK has an entire /8

[nick at foobar.org (Nick Hilliard)]

On 21/09/2012 19:23, Tony Hain wrote:
> App developers have never wanted to be aware of the network.

By not sitting down and thinking about the user experience of a
dual-stacked network, we have now forced them to be aware of the network
and that's not a good thing because they are as clued out about networking
as most network operators are about programming.  If we had designed a
portable and consistent happy-eyeballs API 10 years ago, it would be widely
available for use now.  But we didn't do that because we were thinking
about the network rather than the users.  So now, each dual stack developer
is going to have to sit down and reimplement happy eyeballs for themselves.
 What a waste.

> As far as they
> are concerned it is the network managers job to get bits from the endpoint
> they are on to the endpoint they want to get to. Making them do contortions
> to figure out that they need to, and then how to, tell the network to do
> that adds complexity to their development and support. This is not an IPv6
> issue, it is historic reality.

No, it's a current reality for early venturers into ipv6.  It may become a
future reality in the mainstream if ipv6 takes off in a way that I can't
foresee at the moment.  One day in the future, maybe, it will become less
of an issue if people go back to a single-stack endpoint system.

> And something that is easy to fix by simply deploying a 6to4 relay in each
> AS and announcing the correct IPv6 prefix set to make it symmetric. 

In theory yes.  In practice no.

> event. Those that are doing so intentionally, while providing the long term
> path in parallel, can be described as weaning their customers off the
> legacy. Those that are doing so inadvertently, because they don't care about
> anything but their tiny part of the overall system, will lose customers to
> the provider offering the long term path.

So long as the cost of that is less than the cost of deploying ipv6 and
pushing people in that direction, it's a good business plan in the short
term.  Which is what most people care about.  I'm with you that it's a
hopeless long term business plan, but that's not the world we live in.

Nick