Defects indicated on the interface since the last time the
object was read.
los(0) Loss of Signal was detected.
lof(1) Loss of Frame was detected.
ais(2). Alarm Indication Signal was received from up-stream
node.
lop(3). Loss of Pointer was detected. This happens on DVB
when the connection does not have enough capacity.
lod(4). Loss of Data (congestion) was detected.
rdi(5). Remote Defect Indication was detected.
lol(6). Loss of Lock (frequency outside range) was detected.