10-22
Cisco ONS 15454 DWDM Reference Manual, R8.5
78-18343-02
Chapter 10 Network Reference
10.7.3 Fiber Cut Scenarios
9. On the OPT-BST/OPT-BST-E, the simultaneous LOS-O and LOS-P detection triggers a command
to shut down the amplifier. CTC reports an LOS alarm (loss of continuity), while LOS-O and LOS-P
are demoted. Refer to the Cisco ONS 15454 DWDM Troubleshooting Guide.
10. The OPT-BST/OPT-BST-E card amplifier is shut down within one second.
11. The OSCM laser is shut down.
12. The Node A OPT-PRE card automatically shuts down due to a loss of incoming optical power.
When the fiber is repaired, either an automatic or manual restart at the Node A OPT-BST/OPT-BST-E
transmitter or at the Node B OPT-BST/OPT-BST-E transmitter is required. A system that has been shut
down is reactivated through the use of a restart pulse. The pulse is used to signal that the optical path has
been restored and transmission can begin. For example, when the far end, Node B, receives a pulse, it
signals to the Node B OPT-BST/OPT-BST-E transmitter to begin transmitting an optical signal. The
OPT-BST/OPT-BST-E receiver at Node A receives that signal and signals the Node A
OPT-BST/OPT-BST-E transmitter to resume transmitting.
Note During a laser restart pulse, APR ensures that the laser power does not exceed Class 1 limits. See the
“10.7.2 Automatic Power Reduction” section on page 10-19 for more information about APR.
10.7.3.2 Scenario 2: Fiber Cut in Nodes Using OSC-CSM Cards
Figure 10-15 shows nodes using OSC-CSM cards with a fiber cut between them.
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