Re: [Roll] Something to ADD

[Richard Kelsey <richard.kelsey at ember.com>]

   Date: Tue, 10 Nov 2009 22:27:15 +0100
   From: "Julien Abeille (jabeille)" <jabeille at cisco.com>

   We are talking about DAOs I guess, not DIOs.

Yes.

   I am not sure I understand
   the issue Richard. To me the no-DAO should travel up following the
   prefered parents path, removing all DAO states if any.

Yes, and then after the move the new DAO follows the
new prefered parents' path.  Neither has any affect
on nodes that do not cache DAO information.  If the
set of nodes that do cache DAO information does not
change, then there is no need for the no-DAO.

Here is an example.  We start with this, where A
is the root:

       A
      / \
     B   C
     |
     D
     |
     E

Now D moves to C as its parent:

       A
      / \
     B   C
         |
         D
         |
         E

If only A caches DAO data, then all D needs to do
is send a DAO after the move.  A receives it and
changes its next hop for D and E to be C.

If B and C both cache DAO data, then D needs to send
a no-DAO before the move, to update B, and both D
and E need to send DAOs after the move, so that C
knows that it has downward paths to both of them.

                            -Richard Kelsey