[CUWiN-Dev] IP Autoconfiguration scheme

[Pablo Osuna]

Dear CUWIN community:

My name is Pablo Osuna. I am part of EHAS (www.ehas.org), a spanish
non-profit institution (NGO), whose ultimate goal is improving public
health assistance services in rural areas of Latin American Developing
countries like Cuba, Peru and Colombia. We try to help them to develop
the telecommunications infrastructure in rural establishments
(particularly those that are the most isolated and lack phone line
access).

I am the person in charge of developing a wireless mesh router with
solar energy. I am working on that with an embedded Linux system. At the
moment we have installed some networks in the countries mentioned before
but we would like to improve the design, especially towards an
autoconfiguration scheme.

The wireless router will be part of a mesh IP network and one of my main
concerns is the IP Autoconfiguration. As you probably know there a lot
of theoretical studios on this topic but we can not say the same in the
implementation side.

I just saw your IP schema design. I copy it below:

     We will assign numbers to stations from 10.0/16. The last 16 bits
        are the XOR of the first two octets of the MAC number, the second
        two octets, and the third octets, where the bytes are taken in
        "reading order."  That is, we produce numbers 10.0.A.B from the
        MAC numbers. If the MAC produces A = 0, B = 0 or A = 255, B =
        255, then A and B are assigned randomly.  The netmask is /16.

        (We compute numbers from the MAC to begin with because in the
        common case, a station will boot with the same A and B every time,
        which is useful for diagnostic purposes.)

        The host networks are assigned from 10/8. We assign to each
        Ethernet interface, a network 10.A.B.0, where A and B are computed
        as above from the Ethernet MAC number. If A = 0, we re-assign
        it randomly. The netmask is /24.

Looking at this I would like to ask you: What happens if for example two
nodes get the same IP Address after doing this procedure? I mean, the
probability is very small, but that can happen. Have you predicted this?

Thanks and congratulations for your Project, it looks great!

Pablo