EXFO FTB/IQS-85100G Packet Blazer for FTB-500/IQS-600 - Manual (Page 230)

Test Results
220 FTB/IQS-85100G
Performance Monitoring

SEP (Severely Errored Period) (G.828 only): A sequence between 3 to
9 consecutive SES. The sequence is terminated by a second which is
not a SES.

SEPI (Severely Errored Period Intensity) (G.828 only): Gives the count
of SEP events in available time, divided by the total available time in
seconds.
Far-End

EFS (Error Free Second): Gives the count of the seconds within which
no error occurred or when a defect is detected on the near-end.

EC (Error Count) (G.821 only): Gives the number of bit errors.

EB (Errored Block) (G.828, and G.829): Gives the count of blocks in
which one or more bits are in error.

ES (Errored Second): For G.828, G.829, and M.2101: Gives the count of
the seconds within which one or more anomalies (EB, etc.) occurred
or at least one defect occurred.

SES (Severely Errored Second)
For G.828, G.829 and M.2101: Gives the number of seconds within
which anomalies (FAS (DSn/PDH), EB, etc.) are  30%or at least one
defect occurred.

BBE (Background Block Error) (G.828 and G.829 Line): Gives the count
of Errored Blocks not occurring as part of an SES.