This object represents the best known state of a unit in the stack. The unknown state is not expected to be used, but may exist because of loosely integrated components in the stack. Management applications MUST EXPECT to see the 'unknown' value. The other states are as follows: unitInactive: The device has failed to respond send out periodic update messages, but it still appears to be in the stack. unitOperational: The unit is sending our periodic identification messages and indicates that it is operational, running its complete image. unitLoading: The unit is running is a special operational mode which means that it is unmanaged while it loads a new operational code image. Note that if the stack ever contains units which can download an operational image while still being fully managed then this variable will report 'unitOperational'.