Shutting down specific device

[Drew Moseley <dmoseley mvista com>]

Is there a bit of scripting magic where I can force a specific
network device to shut down?

We have a device that when it is powered down via external switch,
Network Manager handles it but sees a state change to FAILED so it
is marked as invalid.  I'd like to be able to tell Network Manager
that it should be disconnected so it is handled more gracefully.

I've started playing with dbus-send but so far can only manage to
use the sleep and wake commands successfully.

Drew