18-26
Cisco ONS 15454 DWDM Installation and Operations Guide, R6.0
August 2005
Chapter 18 Network Reference
18.7.2 Scenario 2: Fiber Cut in Nodes Using OSC-CSM Cards
8. Node A power monitoring photodiode detects a LOS-O on the OPT-BST/OPT-BST-E card and the
OSCM card detects a LOS (OC3) at the SONET layer. Refer to the Cisco ONS 15454
Troubleshooting Guide or the Cisco ONS 15454 SDH Troubleshooting Guide.
9. Node A power monitoring photodiode detects a LOS-P on the OPT-BST/OPT-BST-E card. Refer to
the Cisco ONS 15454 Troubleshooting Guide or the Cisco ONS 15454 SDH Troubleshooting Guide.
10. On the OPT-BST, 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 Troubleshooting Guide or the Cisco ONS 15454 SDH
Troubleshooting Guide.
11. The OPT-BST/OPT-BST-E card amplifier is shut down within three seconds.
12. The OSCM laser is shut down.
Note The shutdown of the OPT-BST/OPT-BST-E and OSCM cards, which launch power into the cut
fiber, achieves the aim of the Network Optical Safety feature.
13. 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, automatic power reduction (APR) is disabled and the laser power does not
exceed Class 1 limits.
18.7.2 Scenario 2: Fiber Cut in Nodes Using OSC-CSM Cards
Figure 18-12 shows nodes using OSC-CSM cards with a fiber cut between them.
To Next Page
Loading...
