The alarm type field as defined by OSI which is
used to indicate a broad category of what is wrong. The
first 6 values are OSI-defined; refer to CCITT X.733/ISO 10164-4
(for the first 5) and CCITT X.736/ISO 10164-4 (for the last)
for a more complete description.
The value 'operator' is used when an alarm is issued due to an
operator command. The values 'debug' and 'unknown' are for
compatibility with older switches and are used for debugging alarms and
for those which do not fit any of the above, respectively.