mapping l2 network topology

[Freezer <nt3zer () gmail com>]

Hi,
is there any reliable way to detect and map topology of layer 2
devices on the LAN?
i think that knowing layer 2 topology could give a clue about
geographic location of devices.
presence of swithces broadcasting for instance CDP packets could be
easily detected using tcpdump, then I think even more switches support
snmp. but i guess there are plenty of unmanaged 'dumb' devices, which
could not be discovered so simply.

and even if i find out that devices are on network - how to map topology?

maybe some tricks measuring latency? however, doubt its possible due
to switches having really low latencies.

Regards,
Freezer

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