Subject: [nemo] nested requirement?

From: Alexandru Petrescu<[email-masked]>
Date: 18 Dec 2002 18:20:30 +0100

I've been looking at the requirements as presented in the last meeting
minutes.  It's not yet clear to me whether those requirements catch
the nesting aspects.  If yes, then there's probably a new requirement
that has been suggested recently:

   "Nested mobility support between two mobile routers (allowing MR1
    to nest under MR2) is required only when the path from MR2 to
    MR1's HA does not go through MR1 (path considered when both mobile
    routers are at home and no tunnels are in place)."

Consider the following example, where both MRs are at home and where
MR1's mobile network contains HA2.  MR1 belongs to HA1 and MR2 belongs
to HA2.

                                       ----------/
                           -------    |          |
   -----------------------| HA1/BR|---| Internet |
       |                   -------    |          |
       |                               ----------
     -----    ----- 
    | MR1 |  | HA2 |
     -----    ----- 
       |        |   
      ------------  
       |            
     -----    ----- 
    | MR2 |  | LFN |
     -----    ----- 
        |        |  
       ------------ 

In this case, it is possible for the MR1 to go visit AR, together with
MR1 under it (that will not see mobility).  It is also possible for
MR2 to go visit other places.  But it would be probably difficult to
require a nested configuration like this to work:

                        ----------/
            -------    |          |
           | HA1/BR|---| Internet |
            -------    |          |
                        ----------\
                                   \
                                    ----- 
                                   | AR  |
                                    ----- 
                                      |            
                                    -----    ----- 
                                   | MR2 |  | LFN |
                                    -----    ----- 
                                      |        |   
                                     ------------  
                                      |            
                                    -----    ----- 
                                   | MR1 |  | HA2 |
                                    -----    ----- 
                                      |        |  
                                     ------------ 

What do you think, do I miss anything?

Alex