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Cisco ONS 15454 DWDM Reference Manual, R8.5
78-18343-02
Chapter 10 Network Reference
10.7.3 Fiber Cut Scenarios
even though the establishment of successful OSC communication is assurance that any broken fiber is
fixed. If the far-end amplifier responds with a nine-second pulse within 100 seconds, both amplifiers are
changed from pulse mode at reduced power to normal operating power mode.
For a direct connection between TXP or MXP cards, when ALS Auto Restart is enabled and the
connections do not pass through a DWDM layer, a similar process takes place. However, because the
connections do not go through any amplifier or OSC cards, the TXP or MXP cards attempt to establish
communication directly between themselves after a system failure. This is done using a two-second
restart pulse, in a manner similar to that previously described between OSCs at the DWDM layer. The
power emitted during the pulse is below Hazard Level 1.
Warning
In the event that ALS is disabled, a larger amount of invisible laser radiation might be emitted from
the end of the unterminated fiber cable or connector. Do not view the end of the fiber directly with
optical instruments. Viewing the laser output with certain optical instruments (for example, eye
loupes, magnifiers, and microscopes) within a distance of 100 mm may pose an eye hazard.
Note If you must disable ALS, verify that all fibers are installed in a restricted location. Enable ALS
immediately after finishing the maintenance or installation process.
Note For the line amplifier to start up automatically, disable the ALS on the terminal node that is
unidirectional.
10.7.3 Fiber Cut Scenarios
In the following paragraphs, four ALS scenarios are given:
• Nodes using OPT-BST/OPT-BST-E cards (amplified nodes)
• Nodes using OSC-CSM cards (passive nodes)
• Nodes using OPT-BST-L cards (amplified nodes)
• Nodes using OPT-AMP-L, OPT-AMP-C, or OPT-AMP-17-C cards (amplified nodes)
• Nodes using DCN extensions
10.7.3.1 Scenario 1: Fiber Cut in Nodes Using OPT-BST/OPT-BST-E Cards
Figure 10-14 shows nodes using OPT-BST/OPT-BST-E cards with a fiber cut between them.
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