Nokia Optical Diagnostics and Troubleshooting 4A0-265 Exam Questions

Answer : A

The recommended order for the troubleshooting steps is A, as follows:

Retrieve the channel power trace.This step is useful to identify the affected channel and its power level, as well as to check if there are any fluctuations or anomalies in the power trace that could indicate a clock source issue1.

Determine the active clock reference source. This step is necessary to verify which clock source is currently used by the node, and if it matches the expected configuration.The clock source can be either a local oscillator (LO) or a phase-locked loop (PLL) that synchronizes with an external reference2.The active clock source can be determined by using the commandshow interface ot 1/1/lineout detail3.

Switch to alternate clock source (PF). This step is helpful to isolate the problem and confirm if the suspect PF is indeed causing the channel-related alarm.By switching to an alternate clock source, such as another PF or an external reference, the node can recover from the alarm if the original clock source was faulty4.

Replace the suspect PF. This step is the final solution to resolve the issue and restore the normal operation of the node.The suspect PF should be replaced with a new one that has the same specifications and configuration as the original one5.Reference:Nokia Optical Diagnostics and Troubleshooting Course | Nokia,Optical User Guide - Nokia,Alcatel-Lucent 1830 PSS-8 and PSS-16 Photonic Service Switch

Answer : A

1-Day PMs are one of the types of PM data that can be retrieved from an optical network element. 1-Day PMs show measurements collected over the preceding 24 hours, with each hour being a bin. Up to 8 bins are available for data storing, which means that only the most recent 8 hours of data can be accessed. The other types of PM data are 15-Minute PMs, which show measurements collected over the preceding 15 minutes, with each minute being a bin, and Total PMs, which show measurements collected since the last reset of the PM counters.Reference:Nokia Optical Diagnostics and Troubleshooting Course,Nokia 1830 PSS-32 and PSS-16 Photonic Service Switch Release 8.0 Performance Monitoring Reference Guide

Answer : B

The commandshow interface am2125a 1/6/lineout detailis used to retrieve the total output power level of the AM2125A amplifier module. This command displays detailed information about the lineout interface, including the current optical power, wavelength, and status.The total output power level is shown asOutput Power (dBm)in the output of this command1.Reference:Nokia Optical Diagnostics and Troubleshooting Course | Nokia

Answer : D

A Threshold Crossing Alert (TCA) alarm is a type of alarm that indicates that a monitored parameter has crossed a predefined threshold. For example, a TCA alarm can be triggered when the optical power received at a port is too high or too low. The default severity level for a TCA alarm is warning, which means that it does not affect the service but may require attention. The other severity levels are critical, major, and minor, which indicate different degrees of impact and urgency of the alarms. The severity level of a TCA alarm can be changed by the user using the Nokia 1830 Engineering and Planning Tool (EPT) or the Nokia 1350 Optical Management System (OMS).Reference:Nokia Optical Diagnostics and Troubleshooting Course,Nokia 1830 PSS-32 and PSS-16 Photonic Service Switch Release 8.0 Alarms and Conditions Reference Guide

Answer : B

A power adjustment has succeeded conditionally because of gain settings set to higher levels than expected by design. This means that the optical power levels of the amplifier have been adjusted within the acceptable range, but the gain values are higher than the design values. This can cause a performance degradation or instability of the optical signal. The alarm that will raise in this case is ''Amplifier Gain Tilt Adjustments Suspended'' (PWRTILTSUSP). This alarm indicates that the gain tilt adjustments, which are used to compensate for the wavelength-dependent loss of the optical signal, have been suspended due to high gain values. The alarm also suggests lowering the gain values manually or using the EPT tool. The other alarms are incorrect because they either indicate a different type of power adjustment issue or do not exist.Reference:Nokia Optical Diagnostics and Troubleshooting Course,OAM and Diagnostics Guide

Answer : D

The commandshow wavekey wtsource powerdisplays a list of the expected and measured output power for the channels whose admin state is up. This command is useful to monitor the power levels of the channels that are encoded with Wave Keys, which are unique identifiers for wavelength tracking.The command output shows the channel number, wavelength, Wave Key ID, Wave Key Code, expected output power, measured output power, and power difference for each channel1.The command can be used on both OTs and amplifiers that support WT capability2.Reference:Nokia Optical Diagnostics and Troubleshooting Course | Nokia,Optical User Guide - Nokia

Answer : A

In bidirectional configurations, where the same fiber is used to transmit signals in both directions, power adjustments can be performed at both ingress and egress amplifiers. The ingress power adjustments are performed against the ingress amplifiers, which boost the incoming signals from the opposite direction.The egress power adjustments are performed against the egress amplifiers, which boost the outgoing signals from the same direction2. Therefore, the statement A is correct.Reference:Nokia Optical Diagnostics and Troubleshooting Course | Nokia,Optical amplifiers, explained by RP; optical amplification