When I saw this thread starting I thought to myself "No, no, no ... this will
never end well." I decided to stay out of it, but Neil raised an important
point, namely that things are more complicated than what meets the eye. The
state of IPv6 software in the field isn't good, and much of it dates back to
the early years of this century, or even late last century. There was great
enthusiasm and a flurry of activity when IPv6 first saw the light of day, but
the endurance of IPv4 combined with a steady stream of routine, everyday issues
meant that IPv6 started taking a back seat after just a few years. I keep
telling this story about a journalist asking me "When will the Internet change
to IPv6?", to which I replied "Just before it's too late"; it wasn't what he
was expecting to hear, but it was a reflection of daily reality in a commercial
environment, and that hasn't changed. IPv6 remained a draft standard,
accompanied by various additional RFCs and related documents, until it was
finally consolidated in RFC8200 a few years ago; the process took nearly 20
years, and the promotion to full standard was partly prompted by an
administrative change in the RFC process.
Being stuck in the draft standard state isn't in itself unusual, and
interoperability demands from the real world usually iron out any
implementation bumps, but in this respect IPv6 has been in a backwater.
Probably the most widely known and used IPv6 code base came out of the
WIDE/KAME project, but much of it is literally 15-20+ years old, and hasn't
been updated for over a decade. Hence, by today there are dozens, or probably
actually hundreds, of slightly diverging IPv6 implementations in various states
of disrepair. They trace their origins back to RFC2460 from 1998, but each
will have incorporated its own blend of tweaks, fixes, and updates, some from
RFCs and errata, some from I-Ds, and some from in-house developments. Few, if
any, are ready for prime time in the way IPv4 is, and while they all generally
work, IPv6 simply doesn't have the tightly knit development and
interoperability history that IPv4 has.
So ... when will the Internet go IPv6 native? Maybe never. It's a commercial
issue, and there are no overarching considerations at play: IPv4 doesn't cause
global warming, and the ozone layer is safe too. Hence, nobody is likely to
spend time and energy on IPv6 until doing so becomes a source of revenue, and
that will in the first instance mean the whole world catching up with two
decades of neglect.
-- Per
