The operation status of frame. Options: 1. normal(1) -indicates that the shelf is running normally 2. fault(2) -indicates that the shelf is faulty 3. other(3) -indicates that the shelf is in a state other than the previous three states 4. discovery(4)-indicates that the shelf is in the auto discovery state and is to be activated 5. mismatch(5) -indicates that the shelf type is inconsistent with the configuration in the database of device 6. offline(6) -indicates that the shelf is offline or the link of the shelf is down