Re: Why this is broken [was Re: Extending a /64]

[Michael Richardson <[e-mail]>]

Brian E Carpenter <[e-mail]> wrote:
    > On 17-Nov-20 04:26, Tony Whyman wrote:
    >> On 16/11/2020 14:50, Joel M. Halpern wrote:
    >>> Tony, why are you embedding the 39 bit airplane ID into the IPv6
    >>> address.  That seems to be the fundamental thing that then has you
    >>> need very short prefixes, and doing other difficult operations.
    >>>
    >>> And if the answer is "ICAO said so", then we have a problem of really
    >>> smart aviation engineers doing network engineering.
    >>>
    >>> Yours,
    >>> Joel
    >>
    >> Perhaps the best way to answer this question is to look at the alternative.
    >>
    >> Aircraft MNPs are non-topological

    > Thank you for that clear statement. Internet routing *is* topological.
    > Therefore, you cannot use bits in the routing prefix for non-topological
    > information. Therefore, you cannot put 39 magic bits into the routing
    > prefix; the Internet doesn't work like that. End of story. Back to the
    > drawing board.

The airline identifier (the prefix /17 + 15bits airline number = /32) is
topological.

Traffic from whatever peers the aircraft needs to talk to goes through the
airline "HQ" (but: of course, physically attached in many places thanks to
BGP), and then through the mobile IPv6 system to get to the aircraft.   Each
airline has that 24-bit wide mapping table to get the data there over the
OMNI/RAW/etc. link.

    > However, you should be aware that IP addresses are intrinsically
    > forgeable. I'm not sure I would want to fly on an aircraft whose
    > identity might be trivially forged. Also, it would be trivial for
    > an attacker to observe that a particular address belongs to a
    > particular aircraft.

This is an irrelevant non-sequitor.  We have multiple technologies at multiple levels to
protect against this kind of forgery: 802.1x, MACsec, IPsec, BCP38.

--
Michael Richardson <[e-mail]>   . o O ( IPv6 IøT consulting )
           Sandelman Software Works Inc, Ottawa and Worldwide