VeEX MPA User Manual page 512

MPA_e_manual_D07-00-129P_RevA00
Since the Maximum and Minimum receive power levels can vary from one laser
module to another, you should reference the data sheet for information pertaining to a
specific laser module's limits.
Setting Thresholds for M.2120 Performance Events
The M.2120 screen provides a detailed breakdown for errors meeting the ITU-T M.2120
standard. The results table displays errors detected and logged by the SDH protocol
processor by using threshold error performance criteria with respect to either a 15-
minute (TR15) or 24-hour (TR24) evaluation period. Error thresholds can be set directly
from the M.2120 screen.
Threshold Report 15-Minute (TR15) and Reset Threshold Report 15-Minute
(RTR15)
When evaluating TR15, performance events are counted separately, second by second,
over each 15-minute fixed window period. A threshold can be crossed at any second
within the 15-minute period. As soon as a threshold is crossed a 'fail' message is
displayed in the Cur15 column. The performance events continue to be counted to the
end of the 15-minute period, at which time the current performance event counts are
stored in the historical registers and the current performance event registers are reset to
zero. After resetting the registers to zero the 'pass' or 'fail' result moves to the Prev15
column and the performance evaluation continues and records the new result in the
Cur15 column.
If the event is in the fail state, the value of the counter is compared to the reset
threshold (RTR15) at the end of each period. If the count is less than or equal to the
reset threshold, and there has been no unavailable time during that period, a RTR15 is
generated and the state changes back to acceptable. If there has been unavailable time
during the period or the count crosses the RTR15 threshold then the event remains in
the fail state.
Threshold Report 24-Hour (TR24)
The TR24 filter is a 24-hour fixed window. The start and end time for the 24-hour
window must occur on a 15-minute window boundary. TR24s occur as soon as the 24-
hour threshold is reached or exceeded. The resultant pass or fail state displays the
Cur24 column and records to the Prev24 column as the next evaluation period begins.
There is no RTR24 for the 24-hour evaluation period.
To set an evaluation threshold:
SDH Tab
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