[e2e] modularity of address lookup and management

Craig Partridge craig at aland.bbn.com
Fri Nov 3 08:13:37 PST 2006

In message <453D1002.9070605 at isi.edu>, Joe Touch writes:

>> If address control is done in the MAC/device driver layer,
>> then a datagram could trigger one lookup per interface.  If address con=
>> is done by the IP layer, then there are challenges of mapping IP addres=
>> to MAC layers/interfaces (required, as I recall, on outbound where the
>> source IP address usually must but that of the outbound interface).
>When is this 'address control' happening? There's already one lookup per
>packet on arrival to see if it matches one of the interfaces. On
>departure, that typically happens only for packets whose source
>addresses are unassigned.

Hi Joe:

Thanks for a very helpful note.  On this point.  I'm actually looking
at trying to create a unified addressing subsystem for software defined
radios.  So the lookup on arrival at the interface is also part of
the problem.  The broad issue I'm struggling with is whether one needs
to manage addresses separately at each layer, or whether there's a way
to unify all the address management.  A perhaps, less hair raising
version of the question is whether one can devise a way that MACs
can trivially run using any address scheme.  So I could retool the 802.11
MAC to use IP addressing and all would work fine.



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