If vportFuncType is either localBridge(1) or
localOpSwitch(2) type, setting this field to
autoSwitch(3), the default, will allow the port
to switch between the localBridge(1) or localOpSwitch(2)
mode. The forceBridge(4) mode will prevent the
localBridge(1) mode to switch to localOpSwitch(2) mode
even there is only one MAC address is detacted. The
forceSwitch(5) mode prevents the localOpSwitch(2)
mode to switch to localBridge(1) mode. The user
would have to make sure no loop is formed in the
network in this case. The default is autoSwitch(3).