Some of the scenarios we are looking at require that
we be able to keep the same IPv6 address for both registered
and non-registered modes for each tunnel setup - this of course
should be a choice.
I don't know if this is more of an implementation issue or not
but for registered mode I don't want to require the end customer to
manually enter settings via some web page every time
they initiate a new tunnel setup. For example, I want to require
registration but in a way that is automatic and transparent to the
user.