[mobile-ip] Re: New idea for Router Sol/Adv and Mobility - NO new types

[Francis Dupont <Francis.Dupont@enst-bretagne.fr>]

=> this thread was completely messed by the mobile-ip mailing list bug:
I believe a summary is needed in order to understand ideas and
their chain.

   On one hand I agree with Erik that new types are better than overloading 
the
   semantics unnecessarily. The basic problem I am having with this thread is
   understanding the problem it is trying to solve.

=> look at my intro (:-).

   Since the HA is required to be in all possible routing paths to my
   home subnet (else some parts of the world will never contact the node
   when it is mobile), it has to be a function of the last hop router.

=> not exactly. The Home Agent (HA) must be attached to the home link.
If the home link doesn't physically exist then (and only then) your
statement applies.

   The premise of this proposal was that the MN would need to ask the
   HA for a prefix so it could configure its home address.

=> the issue is home link renumbering, in particular when the Mobile
Node (MN) is down for a very long period. This is a real problem
but there are far more important problems, for instance the abyssal
performance of secure mobile IPv6 when a MN is booted in visit
(of course having to learn the HA address and the home address will
not improve this).
 This thread assumes that:
  - the home link is often renumbered
  - DNS is not available in the visit network (if it is available
    then you need only to configure a name as proposed by Compaq folks)
  - home AAA is not available (if it is available then HA and home address
    allocation may/should be done by AAA)
  - statefull autoconfig will never be available!

   Since it knows (presumably via configuration) the address of the
   HA, (and given the HA has to be in the routing path) it already has a
   useable prefix. I have always assumed that the MN is configured with its
   home prefix, then it would use the all-routers anycast address to find the
   HA. In this case the proposed messages are unnecessary. Clearly I need a
   picture to understand why the MN would know its HA, but not its home 
prefix.
   
=> there is a dedicated anycast address for HAs (because if HAs are routers,
not all routers are HAs).
 I agree this topic is a secondary one and we should throw it into the
for further studies stuff. Of course, I'll strongly object if this is
slowing down the mobile IPv6 draft (BTW, is there an I-D 14?).

Thanks

Francis.Dupont@enst-bretagne.fr