The detection interval is
•
for STM-1:
700 sec. for a BER threshold of 10
-9
78 sec. for a BER threshold of 10
-8
•
for STM-4:
188 sec. for a BER threshold of 10
-9
21 sec. for a BER threshold of 10
-8
.
The SD detection itself has a built-in hysteresis of about one magnitude in BER (i.e. if
the SD is set at 10
-8
, it requires a signal better than 10
-9
to clear the SD).
A feature called “fast termination” is implemented and enabled. As soon as the
minimum error count necessary to declare SD is reached, SD is set immediately and
the interval is restarted (i.e. no waiting until the interval is finished). If all frames are
errored, the detection time for the rates mentioned above is approx. 10 ms.
Network configuration
Figure 10-1 Protected ring configuration
NE-D
Tx
Rx
OP
Tx
Rx
OP
NE-C
OP
Rx Tx
OP
Rx
Tx
NE-A
OP
Rx
Tx
NE-B
Tx
Rx
OP
OP
Rx Tx
Tx
Rx
OP
OP = Optical Pack
Network establishment and testing
Connecting the fiber cables
.................................................................................................................................................................................................................................
10-6
Lucent Technologies - Proprietary
See notice on first page
365-374-187
Issue 1, December 2005