Nokia 4A0-265 Nokia Optical Diagnostics and Troubleshooting Exam Practice Test

The statement that when multiple channels pass through a shared port (for example, an amplifier line interface), the total aggregated power reflects the number of channels currently present is TRUE. This means that the more channels are present, the higher the total output power will be, and vice versa. This is because each channel contributes to the total power by its own power level, and the amplifier tries to maintain a constant gain for each channel2. Therefore, the total output power depends on both the input power and the number of channels3. References : Nokia Optical Diagnostics and Troubleshooting Course | Nokia, Optical amplifiers, explained by RP; optical amplification, Amplifier chains, explained by RP; amplifier stages, preamplifier …

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

 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

A passive component in a CDC-F network configuration is the MSH4-FSB Fiber Shuffle Module. This module is used to rearrange the fibers between the CDC-F modules and the wavelength routers, so that each wavelength router can access any of the 96 wavelengths in the C-band. The MSH4-FSB module does not require any power or active components, and it does not perform any optical amplification or switching2. References : Nokia Optical Diagnostics and Troubleshooting Course | Nokia, Nokia 1830 Photonic Service Switch (PSS) | Nokia

The command config powermgmt egress 1/2 adjust status is used to enable or disable the power adjustment feature on the specified egress amplifier. The power adjustment feature is a function that automatically adjusts the output power of an amplifier to compensate for changes in the input power or the number of channels. This feature can be enabled or disabled on both ingress and egress amplifiers, depending on the network configuration and requirements1. Therefore, the statement C is true. References : Nokia Optical Diagnostics and Troubleshooting Course | Nokia

The Customer Release Notes (CRNs) document collects documented solved known issues, new issues discovered after the product software has been released, as well as software upgrade procedures and firmware details. This document is useful for troubleshooting because it can help identify if a problem is related to a known issue or a software bug, and if there is a workaround or a solution available. The CRNs also provide information about the software compatibility and interoperability of different Nokia products and platforms. The other options are incorrect because the EPTUG and the UPG do not contain information about known issues, and the CRNs do not provide instructions for automated provisioning, commissioning, and power balancing functions. References: Nokia Optical Diagnostics and Troubleshooting Course, Nokia Optical Diagnostics and Troubleshooting Exam

 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

The command show interface 1/8/UNEIN detail is used to retrieve the total optical power detected at the ingress interface of a Raman amplifier. This command displays detailed information about the UNEIN interface, which is the unidirectional east input interface of the Raman amplifier. The total optical power detected at the UNEIN interface is shown as Input Power (dBm) in the output of this command1. References : Nokia Optical Diagnostics and Troubleshooting Course | Nokia

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

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.

The exhibit shows a conditions list from the 1830 PSS GUI, which displays the alarms and events that occur on the network elements. The total number of alarms reported is equal to the number of rows that have a red or yellow icon in the Severity column, indicating a critical or major alarm. In this case, there are 7 rows with such icons, so the total number of alarms is 7. The number of service affecting alarms is equal to the number of rows that have a “Yes” valuein the Service Affecting column, indicating that the alarm affects the service quality or availability. In this case, there are 5 rows with such values, so the number of service affecting alarms is 5. The number of conditions is equal to the total number of rows in the table, regardless of their severity or service affecting status. In this case, there are 7 rows in the table, so the number of conditions is 7. References : Optical User Guide - Nokia, Security Target Nokia 1830 Photonic Service Switch (PSS)

A single directional fiber cut is occurring between two amplifiers in unidirectional configuration with Raman pump. Multiple services are crossing the affected span. The node(s) that will report an Incoming Payload LOS alarm are both Node A and Node C. An Incoming Payload LOS alarm indicates that there is no or very low signal at the input port of a node. In the exhibit, Node A will report this alarm because it will not receive any signal from Node B due to the fiber cut. Node C will also report this alarm because it will not receive any signal from Node D due to the fiber cut. The Raman pump in Node A does not prevent this alarm, as it only amplifies the signal in the forward direction, not the backward direction. The other options are incorrect because they either ignore one of the nodes that will report the alarm or assume that the Raman pump has an effect on the backward direction. References: Nokia Optical Diagnostics and Troubleshooting Course, OAM and Diagnostics Guide