Re: comment on unmanaged analysis presentation/doc

[Paul Vixie <paul@vix.com>]

> > and there's a closure: whenever it becomes reasonable for other
> > reasons to run ipv6-only, we won't need the 6to4 tunnels.
> 
> what is reasonable in one place may not be reasonable in another.  we
> will still need tunnels to connect to those places where native v6 is
> not reasonable.

the simple model of where that could happen is

1. one side
2. the middle
3. the other side

the more interesting model, boiled down to the assymetric tcp case, is:

a. the initiator
b. the initiator's upstream
c. somebody out in the middle
d. the responder's upstream
e. the responder

so far on this list i've seen "a" and "e" ruled out as places to put
protocol-translation/bridging machinery, though a tunnel from "a" or
"e" to some kind of "c" seems popular.  every time anybody mentions
asking "b" or "d" to do this they get shot down, which is too bad,
since (1) they already have a service provision relationship with a
party who evidently wants a new service, (2) they tend to have more
technical know-how than their customers, (3) topologically these
are the most-bang-for-the-littlest-cost, and finally (4) we can stop
talking about it since it's just nat or an application layer proxy at
that point, not in need of any standardization work.