However, if there was a reasonable translation mechanism available which allowed IPv6-only end systems to access IPv4-only content, I think the picture would look quite different.
Doesn't deploying a 6to4 relay in the content provider network, along with IPv6 access to the content provider network, exactly meet this requirement? I agree that it is better if the mechanism can be installed in the eyeball ISP's network, but the fact is that the majority of content providers connect to the Internet via an ISP, so if there was a concerted effort to get content-hosting ISPs to install this mechanism, we would have solved much of this problem.
Designing a universally-general translation mechanism seems hard, and seems likely to suffer from many of the same problems as IPv4-IPv4 NAT; perhaps as an interim measure, however, for the millions of Internet users for whom the network mainly means 80/tcp, the mechanism doesn't have to be universally-general. Perhaps it just has to be good enough.
Agreed. Good enough might be a bit more than port 80, i.e. some more popular IM and P2P ports, but we already have all the pieces needed for this type of ALG to run on a Linux or BSD system. It's just a matter of someone putting together a good HowTo document which could be posted here <http://www.getipv6.info>.
Perhaps the assignment of IPv4 addresses to end users could become a premium service available to those who need them, leaving cheaper, IPv6-only service for everybody else.
I'm quite sure that this WILL happen within a year or so. Lots of ISPs have already gotten their IPv6 through the trial phase and already offer IPv6 access service, or are about to offer it. The difference between today, and 1995 when the Internet went exponential, is that in 1995 there were lots and lots of people with IPv4 networking experience, and IPv4 server experience. Out of that set of people, the early adopters and pioneers naturally formed a critical mass which created new ISPs and new Internet services. But today, we are still struggling to get enough people up to speed on IPv6. A lot of IPv4 people have so little IPv6 knowledge that we continually see the "Three Blind Men and an Elephant" syndrome. We have got to get beyond that which is why I urge everybody on this list to check this ARIN page http://www.getipv6.info/index.php/Educating_Yourself_about_IPv6 Either use it to further your own education, or add some advice/resource that will be of use to others. Every contribution of information, no matter how small, is useful. --Michael Dillon