The optional Backed Up Status parameter, when present in an alarm notification, specifies whether or not the object emitting the alarm has been backed-up, and services provided to the user have, therefore, not been disrupted.
This is consistent with the ITU-T X.733 definition.

Value is one of the following:
- "BACKED_UP"
- "NOT_BACKED_UP".

Readable by NMS? Yes
Writeable by NMS? No
Invariant? Yes
