I would love to see a Mac Address forwarding table grab in observium for L2 devices.
Maybe it's already there, but I couldn't find it.

In NetDisco, this feature is implemented using the 'macsuck' tool.
http://www.netdisco.org/readme.html#glossary

I've implemented it before in sloppy perl using the Bridge mib.
http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094a9b.shtml

The gist for collection is:
- determine the list of active vlans
- for each vlan get a list of mac addresses per 'bridge port'
- lookup a translation of bridgeport to ifindex

If you correlate this data with a global ARP table and DNS, you get a killer feature.

"Lookup the switch port where a given host was last seen. (and hopefully where it still is)"

Because this can be a pretty dynamic dataset, you'll also probably want to maintain the list by putting a last seen datestamp and rolling out old entries.

I think I've found a few hints at some development interest in the past about this sort of feature.

Has it gotten any traction?

Cheers,

Joel