On dinsdag, jun 17, 2003, at 17:05 Europe/Amsterdam, Ronald van der Pol
wrote:
There is a big difference between planning/engineering for a transition
and planning/engineering for a coexistance. There seem to be forces
trying to steer to the latter. Seems like an important question. Why
would we want an internet with two protocols with the same
functionality
running in parallel? Should that be the goal?
I'm sure there are people who are sabotaging v6 in a subtle way by
encouraging dual stack: after all, if everyone still runs IPv4 in
addition to IPv6, _they_ can continue to run v4-only. Other than that I
think the implied assumption is that people will drop v4 at some point
in the (distant) future.
For any particular application and group of users, and in order to
switch over seamlessly, it is necessary that all servers become dual
stack, then clients can switch (without the need to run dual stack) and
after that the servers can drop IPv4. The problem here is that for
client-server applications such as the web and email, IPv4 isn't an
issue because the relative number of servers is tiny and clients can
use NAT without problems. And for peer-to-peer, _everyone_ is a server
so _everyone_ has to run dual stack before it's possible to drop IPv4.
Good thing switching to IPv6 is so easy, or it would never happen.