[Cu-wireless] new network design

David Young dyoung at ojctech.com
Thu Aug 8 20:55:03 CDT 2002

Here is the new network design that Stephane and I have come up with
this evening.


        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.

        We run OSPF in point-to-multipoint mode on each wireless
        interface.  The wireless and wired interfaces should be configured
        with 'network zzzzz/x area 0' clauses under the 'router ospf'
        command.  All other interfaces are run in passive mode (i.e.,
        no OSPF Hellos are sent).


        We will use channel 11.  The SSID is 'cuw', all lower case,
        without the single quotes.

Known Limitations
----- -----------

	Missing from this design are authentication, naming, etc.

        We have not solved the BSSID partitioning problem. We will have
        to watch out for this (perhaps Prism-based cards such as ours
        are not affected).


        Stephane will begin an implementation for Linux and for his
        Soekris board right away.

        I will begin Sunday or Monday to modify the CD-ROM to implement
        the new network design.


David Young             OJC Technologies
dyoung at onthejob.net     Engineering from the Right Brain
                        Urbana, IL * (217) 278-3933

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