Can be called when an interface goes down.
        FIXME: doesn't really do anything at this point.

def intf_down(self, interface):
        '''
        Can be called when an interface goes down.
        FIXME: doesn't really do anything at this point.
        '''
        intf = self._devinfo.get(interface, None)
        if intf and self._devupdown_callback:
            self._devupdown_callback(intf, 'down')