(ngtrans) NAT-PTv02 update

[Brian E Carpenter]

> >- Brian Carpenter suggested that the group needs to consider how
> >this technique would combine with the various other transition
> >techniques, and API issues it raises.

I did, and I'm still worried about that, but I think it's oustide
the scope of this particular document. It is more a question of
how applications layer code can be written in such a way that it
doesn't care whether it's running over IPv4 with or without traditional
NAPT, IPv6, either half of a dual stack, or a v4/v6 translator. 

   Brian