but isn't it therefore
also the case that if the home agent becomes unreachable for more than
7 minutes, regular MIP6 also breaks for the same reason and the mobile
node loses connectivity?
> 5.3.3 Layering Identity
...
> An alternative approach is to use a distinct protocol element
placed
> between the transport and internet layers of the protocol stack.
The
> advantage of this approach is that it would offer a consistent
form
> of mapping between identities and locators for all forms of
transport
> protocols. However this protocol element would not be explicitly
> aware of sessions and would either have to discover the
appropriate
> identity / locator mapping for all identity-addressed packets
passed
> from the transport protocol later, irrespective of whether such a
> mapping exists and whether this is part of a session context, or
have
> an additional mechanism of signaling to determine when such a
mapping
> is to be discovered and applied. At this level there is also no
> explicit knowledge of when identity / locator mapping state is no
> longer required, as there is no explicit signaling of when all
flows
> to and from a particular destination has stopped and resources
> consumed in supporting state can be released.
But there is knowledge, even with UDP, when a socket is closed (in
the worst case because the process that opened it goes away). I think
that because of some sort of layering religion, we tend to neglect
the fact that socket state exists and gets explicitly deleted, and
this should be exploited as the trigger for deleting id/loc
mapping state.
Brian