Cisco ONS 15454 DWDM Manual page 85

Chapter 1 General Troubleshooting
Figure 1-32
Starting Condition
Until the VOA has completed all the phases shown in
activated.
1.13.1.1 Phase 1: Incoming Signal Validation
The Incoming Signal Validation phase checks to see that the optical interface connection is valid and that
the optical power level is appropriate.
Cisco MetroPlanner calculates the VOA Attenuation Reference value to allow only supported MSTP
interfaces to overcome the power start-up (Pstart-up) acceptance level. (Refer to the "Network
Reference" chapter of the Cisco ONS 15454 DWDM Reference Manual.)
If the interface that is connected has a power value outside the allowed range, the Phase 1 check prevents
OCHNC turn-up.
1.13.1.2 Phase 2: Valid Signal Detected
If Phase 1 indicates that the signal is valid, an automatic iterative attenuation adjustment on the VOA
takes place to reach a power target on the photodiode downstream of the VOA.
78-17742-02
VOA Startup Procedure
OCH-NC Circuit not created
(ADD Port is IS-AINS)
VOA is DISABLE
(VOA Attenuation > 40 dB)
Incoming Signal Validation
(ADD Port becomes IS)
Phase 1
VOA is ACTIVE
(VOA Attenuation = VOA Attenuation Ref.)
TXP/MXP card activated
(Valid signal detected)
Phase 2
POWER ADD > Pstart
(VOA starts an internal procedure
to adjust the attenuation
Channel Power Setpoint Locking
(ADD Port shows a Degr. Low Alarm)
Phase 3
VOA attenuation adjustment (Safe Mode)
(VOA completes locking procedure)
Channel Power Control Mode fully activated
(ADD Port IS and green)
Phase 4
VOA switch in Power CTRL.
(Channel POWER = VOA Power Ref.)
(VOA ATT.
OCH-NC circuit successfully built-in
VOA Attenuation Ref.)
Figure
Cisco ONS 15454 DWDM Troubleshooting Guide, R7.0.1
1.13.1 VOA Startup Phases
1-32, the power control mode is not fully
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