it's mostly just a wrapper around snmpit_intel - this is because, when doing
MAC-based VLANs, you never have to talk to more than one switch. When we switch
to doing port-based VLANs with Intels (something we should do soon, but will
take some experimenting), it will likely become a more full-fledged layer.

Not at all debugged yet - won't be able to do that until we have the
mini-testbed more funcitonal.