Cisco ONS 15454 DWDM Reference Manual page 386

8.11.8 Layer 2 Over DWDM Protection
A FAPS switchover happens in the following failure scenarios:
DWDM line failures caused by a fiber cut
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Unidirectional failure in the DWDM network caused by a fiber cut
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Fiber pull on the master card trunk port followed by a hard reset on the master card
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Hard reset on the master card
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Hard reset on the slave card
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An OTN failure is detected (LOS, OTUK-LOF, OTUK-LOM, or OTUK-LOM on the DWDM
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receiver port in the case of ITU-T G.709 mode)
Trunk ports are moved to OOS,DSBLD (Locked,disabled) state
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Improper removal of XFPs
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A FAPS switchover does not happen in the following scenarios:
Slave card trunk port in OOS,DSBLD (Locked,disabled) state followed by a hard reset of the slave
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card
OTN alarms raised on the slave card trunk port followed by a hard reset of the slave card
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Dual failure in the VLAN ring caused by fiber pull on the master and slave cards and restoration of
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a single failure
Dual failure in the VLAN ring caused by the trunk port of master and slave cards in OOS,DSBLD
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(Locked,disabled) state and restoration of a single failure by placing one trunk port in IS state
Dual failure in the VLAN ring due to the trunk port of master and slave cards in OOS,DSBLD
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(Locked,disabled) state followed by a hard or soft reset of the master card
Cisco ONS 15454 DWDM Reference Manual, R8.5
8-66
Chapter 8 Transponder and Muxponder Cards
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