信頼できるNokia Optical Network Services Expert 4A0-265問題集PDF 2024年04月25日最近更新された問題
必ず合格できるNokia 4A0-265試験正確な40問題と解答あります
Nokia 4A0-265認定試験は、Nokia Optical Diagnostics and Troubleshooting Certificationとしても知られており、光ネットワーキング分野のプロフェッショナルの知識とスキルを認定する業界公認の認定試験です。試験は、候補者が光ネットワークのトラブルシューティングと診断を行い、障害を特定して解決し、パフォーマンスを向上させる能力をテストするように設計されています。Nokiaの認定試験は、プロフェッショナルが通信業界でスキルを向上させ、キャリアを進めるための素晴らしい方法です。
Nokia 4A0-265 認定試験は、Nokiaの技術を使用して光ネットワークの診断とトラブルシューティングの専門家になりたいと思っている専門家向けに設計されています。この認定は、ネットワーク管理者、エンジニア、および技術者向けに理想的であり、光ネットワーク技術における熟練度を示したい人に適しています。
質問 # 22
Which of the following Performance Measurement (PM) type is NOT typically retrieved at an Optical Transponder (OT) line interface?
- A. Ethernet collision counters
- B. Digital Wrapper (DW)
- C. Optical Power Received (OPR)
- D. Forward Error Correction - Errors Counted (FEC-EC)
正解：A
解説：
Explanation
Performance Measurement (PM) is a feature that collects and reports various statistics related to the performance of an optical network element. PM data can be retrieved at different levels, such as Optical Channel (OCh), Optical Channel Data Unit (ODU), Optical Channel Transport Unit (OTU), and Ethernet. An Optical Transponder (OT) is a device that converts an electrical signal into an optical signal and vice versa. An OT has two interfaces: a client interface and a line interface. The client interface connects to the service provider network, while the line interface connects to the optical transport network. At the OT line interface, PM data can be retrieved for the OCh, ODU, OTU, and Digital Wrapper (DW) levels. The DW is a layer that encapsulates the client signal and provides overhead information for monitoring and management purposes.
Ethernet collision counters are not typically retrieved at the OT line interface, as they are related to the Ethernet level, which is usually monitored at the client interface. References: Nokia Optical Diagnostics and Troubleshooting Course, Nokia 1830 PSS-32 and PSS-16 Photonic Service Switch Release 8.0 Performance Monitoring Reference Guide
質問 # 23
Which of the following CLI commands displays a list of the expected and measured output power for the channels whose admin state is up?
- A. config wavekey power detail
- B. show wavekey wtsource power
- C. config wavekey summary
- D. show wavekey wtsource
正解：B
解説：
Explanation
The command show wavekey wtsource power displays 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. References : Nokia Optical Diagnostics and Troubleshooting Course | Nokia, Optical User Guide - Nokia
質問 # 24
Consider the exhibit. Given the following power readings, what is the calculated span loss from Node A to Node B?
- A. 10.0 dB
- B. 5.0 dB
- C. 2.0 dB
- D. 8.0 dB
正解：A
解説：
Explanation
The calculated span loss from Node A to Node B is 10.0 dB. Span loss is the difference between the optical power transmitted and received at two points in a network. It can be calculated by subtracting the received power from the transmitted power. In the exhibit, the transmitted power from Node A to Node B is +7.5 dBm, and the received power at Node B from Node A is -2.5 dBm. Therefore, the span loss is +7.5 dBm - (-2.5 dBm) = 10.0 dB. The other options are incorrect because they do not match the calculation. References: Nokia Optical Diagnostics and Troubleshooting Course, Pluggable Optical Modules: Transceivers for the Cisco ONS Family Data Sheet
質問 # 25
Suppose a channel-related alarm is reported on an 1830 PSS node, and is related to a possible Wave Keys clock source issue. What is the recommended order for the following troubleshooting steps?
- A. 1. Replace the suspect PF.
2. Retrieve the channel power trace.
3. Switch to alternate clock source (PF).
4. Determine the active clock reference source. - B. 1. Determine the active clock reference source.
2. Replace the suspect PF.
3. Retrieve the channel power trace.
4. Switch to alternate clock source (PF). - C. 1. Retrieve the channel power trace.
2. Replace the suspect PF.
3. Determine the active clock reference source.
4. Switch to alternate clock source (PF). - D. 1. Retrieve the channel power trace.
2. Determine the active clock reference source.
3. Switch to alternate clock source (PF).
4. Replace the suspect PF.
正解：D
解説：
Explanation
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 command show 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 replacedwith a new one that has the same specifications and configuration as the original one5. References : Nokia Optical Diagnostics and Troubleshooting Course | Nokia, Optical User Guide - Nokia, Alcatel-Lucent 1830 PSS-8 and PSS-16 Photonic Service Switch
質問 # 26
What is the default severity level for a Threshold Crossing Alert (TCA) alarm?
- A. Critical
- B. Minor
- C. Warning
- D. Major
正解：C
解説：
Explanation
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). References: Nokia Optical Diagnostics and Troubleshooting Course, Nokia 1830 PSS-32 and PSS-16 Photonic Service Switch Release 8.0 Alarms and Conditions Reference Guide
質問 # 27
Which of the following statements best describes the output of the CLI command: show wavekey wtmonitor
1/6/LINE summary?
- A. A list of the unexpected channels detected against the selected interface.
- B. A list of all channels detected against the selected interface, including Wave Keys pair, channel status, expected and measured power, allowed deviation, and tolerance.
- C. A list of all channels detected against the selected interface (in and out); it shows if a Wave Keys pair is expected, if a Wave Keys pair is received, and if the received Wave Keys pair is unexpected.
- D. A list of all channels on this interface for which any Wave Keys pair is being received.
正解：C
解説：
Explanation
The command show wavekey wtmonitor 1/6/LINE summary displays a list of all channels detected against the selected interface (in and out); it shows if a Wave Keys pair is expected, if a Wave Keys pair is received, and if the received Wave Keys pair is unexpected. A Wave Keys pair is a pair of unique identifiers that are transmitted along with an optical channel to provide channel identification and monitoring functions. The command can be used to verify the presence and correctness of the Wave Keys pairs on an interface and to detect any mismatch or misconfiguration. The other options are incorrect because they either describe a different command or provide incorrect information. References: Nokia Optical Diagnostics and Troubleshooting Course, OAM and Diagnostics Guide
質問 # 28
Which of the following statements best describes the output of the command: show xc 1?
- A. A list of all boards on all nodes that this cross-connection passes through, along with expected power levels, measured power levels, and allowed power deviations.
- B. A list of boards that this cross-connection passes through on the local node, along with administrative/operational states, expected power levels, and measured power levels.
- C. OCH trail name, ITU channel, administrative/operational states, protection states, and Wave Keys for both directions.
- D. A list of cross-connections, including A-end, Z-end, frequency, ID number, OCH trail name, and administrative/operational states.
正解：D
解説：
Explanation
The command show xc 1 displays a list of cross-connections, including A-end, Z-end, frequency, ID number, OCH trail name, and administrative/operational states. A cross-connection is a logical connection between two ports on an optical network element that allows the transmission of an optical signal from one port to another.
The command can be used to view the configuration and status of the cross-connections on a node or a network. The other options are incorrect because they either describe a different command or provide incorrect information. References: Nokia Optical Diagnostics and Troubleshooting Course, OAM and Diagnostics Guide
質問 # 29
Consider the exhibit.
Which type of loopback is applied?
- A. Line port terminal Ioopback
- B. Line port facility Ioopback
- C. Client port terminal Ioopback
- D. Client port facility loopback
正解：C
解説：
Explanation
The exhibit shows a diagram of an OT module with a client port and a DWDM port. The client port is looped back to itself with an OEO (Optical-Electrical-Optical) device. This means that the signal received by the client port is converted to an electrical signal, then back to an optical signal, and then transmitted back to the same port. This type of loopback is called a client portterminal loopback. It is used to test the functionality of the client port without involving the DWDM port or any other network element4. A client port facility loopback would involve looping back the signal from the DWDM port to the client port. A line port facility loopback would involve looping back the signal from another OT module or network element to the DWDM port. A line port terminal loopback would involve looping back the signal from the DWDM port to itself5. References : Nokia Optical Diagnostics and Troubleshooting Course | Nokia, Loopback - Wikipedia
質問 # 30
Which of the following statements about the alarm masking mechanism is TRUE?
- A. The alarm masking mechanism makes sure that alarms are always present on the downstream interfaces to facilitate the troubleshooting process.
- B. The alarm masking mechanism always forwards masked alarms to an external Network Management System (NMS) for alarm correlation.
- C. The alarm masking mechanism preserves the events' original time stamps, when related alarms gets hidden and then eventually displayed because of the mechanism itself, so that the user can still know the date and time of the original issue.
- D. The alarm masking mechanism updates the events' original time stamps when it masks/shows alarms, so that when an alarm is not masked anymore, the user can see the updated date and time associated with the original issue.
正解：C
解説：
Explanation
The alarm masking mechanism is a feature of the 1830 PSS that prevents unnecessary alarms from being displayed on the GUI or forwarded to an external NMS when they are caused by a known fault or maintenance activity. For example, if an optical link is down due to a fiber cut, there is no need to show alarms for all the downstream interfaces that are affected by the link failure. The alarm masking mechanism hides these alarms until the root cause is resolved, and then shows them again if they persist. The alarm masking mechanism preserves the events' original time stamps when it masks/shows alarms, so that when an alarm is not masked anymore, the user can see the original date and time associated with the issue. This helps to identify and troubleshoot problems more accurately and efficiently. References : Optical User Guide - Nokia, Alcatel-Lucent 1830 PSS-8 and PSS-16 Photonic Service Switch
質問 # 31
Which of the following statements about the Wavelength Tracker (WT) capability is TRUE?
- A. Wave Keys are originated by optical amplifiers.
- B. WT uses a unique identifier based on a pair of numbers encoded by Optical Transponders OTs) into each service wavelength direction.
- C. WT is compatible with other vendor domains, but the user must make sure that Wave Keys are unique on the crossed domains.
- D. WT uses a unique identifier based on a pair of numbers encoded by Raman amplifiers into each service wavelength direction.
正解：B
解説：
Explanation
The statement that WT uses a unique identifier based on a pair of numbers encoded by Optical Transponders (OTs) into each service wavelength direction is TRUE. WT is a feature of the 1830 PSS that allows for automatic identification and tracking of wavelengths across different network elements and domains. WT uses Wave Keys, which are unique identifiers composed of two numbers: a Wave Key ID and a Wave Key Code. The Wave Key ID identifies the OT that generates the wavelength, while the Wave Key Code identifies the wavelength itself within a given OT6. The Wave Keys are encoded by OTs into each service wavelength direction using phase modulation, and can be decoded by other OTs or amplifiers that have WT capability.
WT enables various applications and benefits, such as simplified commissioning, automated wavelength routing, enhanced fault localization, and improved network security. References : Nokia Optical Diagnostics and Troubleshooting Course | Nokia, Optical User Guide - Nokia, Alcatel-Lucent 1830 PSS-8 and PSS-16 Photonic Service Switch
質問 # 32
Suppose a "Channel Absent" alarm is reported on an 1830 PSS node. What is the recommended order for the following troubleshooting steps?
- A. 1. Retrieve the cross-connection (XC) details and see what virave Keys should be present.
2. Go to the suspected troubled node / card / port and look at Wave Keys (in / out).
3. Retrieve the channel power trace.
4. Check observed Wave Keys against expected Wave Keys. - B. 1. Check observed Wave Keys against expected Wave Keys.
2. Go to the suspected troubled node / card / port and look at Wave Keys (in / out).
3. Retrieve the channel power trace.
4. Retrieve the cross-connection (XC) details and see what Wave Keys should be present. - C. 1. Go to the suspected troubled node / card / port and look at Wave Keys (in / out).
2. Retrieve the cross-connection (XC) details and see what Wave Keys should be present.
3. Check observed Wave Keys against expected Wave Keys.
4. Retrieve the channel power trace. - D. 1. Retrieve the channel power trace.
2. Retrieve the cross-connection (XC) details and see what Wave Keys should be present.
3. Go to the suspected troubled node / card / port and look at Wave Keys (in / out).
4. Check observed Wave Keys against expected Wave Keys.
正解：D
解説：
Explanation
The recommended order for the troubleshooting steps is B, 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 channel absent issue1.
* Retrieve the cross-connection (XC) details and see what Wave Keys should be present. This step is necessary to verify which Wave Keys are expected to be present on the node, card, and port based on the XC configuration2. Wave Keys are unique identifiers for wavelength tracking that are encoded by Optical Transponders (OTs) into each service wavelength direction3.
* Go to the suspected troubled node / card / port and look at Wave Keys (in / out). This step is helpful to compare the observed Wave Keys with the expected Wave Keys, and to locate the source of the problem. If a Wave Key is missing or mismatched, it means that there is a channel absent issue on that node, card, or port4.
* Check observed Wave Keys against expected Wave Keys. This step is the final solution to resolve the issue and restore the normal operation of the node. The observed Wave Keys should match the expected Wave Keys based on the XC configuration. If not, the XC configuration should be corrected or the faulty node, card, or port should be replaced5. References : Nokia Optical Diagnostics and Troubleshooting Course | Nokia, Optical User Guide - Nokia, Alcatel-Lucent 1830 PSS-8 and PSS-16 Photonic Service Switch
質問 # 33
A "Power Adjustment Required" alarm was raised on the ingress amplifier in slot 1/10. Which of the following commands should be entered to manually adjust the related amplifier optical power levels?
- A. config powermgmt ingress 1/10 adjust
- B. config powermgmt ingress 1/10 scot
- C. config powermgmt ingress 1/10 power adjustment
- D. config powermgmt ingress 1/10
正解：A
解説：
Explanation
A "Power Adjustment Required" alarm is raised when the optical power levels of an amplifier are out of the expected range and need to be adjusted. To manually adjust the related amplifier optical power levels, the command config powermgmt ingress 1/10 adjust should be entered. This command will initiate a power adjustment process for the ingress amplifier in slot 1/10, which is the input port for the optical line signal. The command will also display the status and results of the power adjustment, such as success, failure, or conditional success. The other commands are incorrect because they either do not initiate a power adjustment process or have invalid syntax. References: Nokia Optical Diagnostics and Troubleshooting Course, OAM and Diagnostics Guide
質問 # 34
Consider the exhibit. A single directional fiber cut is occurring between two amplifiers in bidirectional configuration. Which node(s) will report a "LD Input LOS" alarm?
- A. Node C only
- B. Node A and Node B
- C. Node B only
- D. Node A only
正解：C
解説：
Explanation
The exhibit shows a diagram of a network of nodes and edges, where a single directional fiber cut is occurring between two amplifiers in bidirectional configuration. The node that will report a "LD Input LOS" alarm is node B only. A "LD Input LOS" alarm indicates that the input signal to the laser diode (LD) of an amplifier is lost or below the threshold3. In this case, node B will not receive any signal from node A due to the fiber cut, and will generate this alarm. Node A will not report this alarm, because it can still receive a signal from node C through the other fiber. Node C will not report this alarm either, because it is not directly affected by the fiber cut between node A and node B. References : Nokia Optical Diagnostics and Troubleshooting Course | Nokia, Troubleshooting Guide for Synchronous Digital Hierarchy - Cisco
質問 # 35
Which of the following is NOT a characteristic of an Optical Supervisory Channel Loss of Signal (OSC LOS) issue, in case that no "LD Input LOS" alarms are raised against the involved amplifiers?
- A. A "Data Link Down" alarm is raised on the adjacent node.
- B. Traffic does not pass between the local and adjacent nodes.
- C. An "Incoming SUPVY LOS" alarm is raised on the local node.
- D. A "Power Adjustment Required" alarm is eventually raised on the local node.
正解：C
解説：
Explanation
The statement that an "Incoming SUPVY LOS" alarm is raised on the local node is NOT a characteristic of an Optical Supervisory Channel Loss of Signal (OSC LOS) issue, in case that no "LD Input LOS" alarms are raised against the involved amplifiers. An "Incoming SUPVY LOS" alarm indicates that the input signal of the Optical Supervisory Channel (OSC) is lost or below the threshold6. The OSC is a bidirectional channel that connects two adjacent nodes in a DWDM network and carries OAM information and other services7. An OSC LOS issue can occur due to a fiber cut, a defective or dirty OSC fiber, or a faulty OSC transmitter or receiver8. However, if there is no "LD Input LOS" alarm raised against the involved amplifiers, it means that there is no loss of signal on the line interface of the amplifier, which carries both service channels and OSC channels9. Therefore, an "Incoming SUPVY LOS" alarm on the local node is not related to an OSC LOS issue, but rather to an OSC configuration issue or a faulty OSC card10. References : Nokia Optical Diagnostics and Troubleshooting Course | Nokia, Optical User Guide - Nokia, Alcatel-Lucent 1830 PSS-8 and PSS-16 Photonic Service Switch
質問 # 36
Consider the exhibit. Given the following power readings, what is the calculated span loss from Node A to Node B?
- A. 2.5
- B. 11.5
- C. 1.5
- D. 8.0
正解：D
解説：
Explanation
The exhibit shows a diagram of a network with two nodes, Node A and Node B, connected by a fiber span.
The diagram also shows the power readings at different points of the span. The calculated span loss from Node A to Node B is the difference between the output power at Node A and the input power at Node B. According to the diagram, the output power at Node A is +3.5 dBm and the input power at Node B is -4.5 dBm.
Therefore, the span loss from Node A to Node B is 3.5 - (-4.5) = 8.0 dB.
質問 # 37
What is the typical severity level of a "Loss of Signal" (LOS) alarm?
- A. Critical
- B. Warning
- C. Minor
- D. Major
正解：A
解説：
Explanation
A "Loss of Signal" (LOS) alarm is a critical alarm that indicates that there is no or very bad signal at the physical interface. LOS alarm is also raised when the signal level drops below the threshold, at which a high bit error rate (BER) is predicted. LOS alarm can be caused by physical damage, power outage, or misconfiguration of the equipment. LOS alarm can affect the service availability and performance of the optical network. Therefore, it is typically assigned a critical severity level, which means that it requires immediate attention and resolution2. Other severity levels are major, minor, and warning, which indicate different degrees of impact and urgency of the alarms. References: Troubleshooting Guide for Cisco NCS
1002, T1: A Survival Guide, M-series SONET/SDH alarms and troubleshooting tips
質問 # 38
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