On: The Future Without IPv6

Here's a good explanation of what went wrong:

http://cr.yp.to/djbdns/ipv6mess.html

"The IPv6 designers made a fundamental conceptual mistake: they designed the IPv6 address space as an alternative to the IPv4 address space, rather than an extension to the IPv4 address space."

I can highly recommend reading RFC1365 ( http://www.faqs.org/rfcs/rfc1365.html ) which defines IP extension blocks to provide huge address spaces within IPv4 while retaining full downward compatibility with legacy routers and hosts. Such extension blocks should also be compatible with NAT and jumbo frames.