4A0-265 - Nokia Optical Diagnostics and Troubleshooting

The statement that best describes the Forward Error Correction (FEC) technique is C. FEC is a technique used in digital communication to improve the accuracy and reliability of data transmission. By adding redundant information to the transmitted data, FEC enables the receiver to detect and correct errors without retransmission or other error correction techniques11. FEC is effective only above a specified OSNR threshold, which is the minimum optical signal-to-noise ratio required for error-free transmission with FEC enabled. If the OSNR falls below this threshold, FEC cannot correct all errors and data quality degrades significantly. References : Nokia Optical Diagnostics and Troubleshooting Course | Nokia, Optical User Guide - Nokia, Forward Error Correction (FEC) - Online Tutorials Library

The Wavelength Router (WR8-88) block is a device that can route optical signals based on their wavelengths. It can also perform wavelength conversion, multiplexing, and demultiplexing functions. The Wavelength Router (WR8-88) block is part of the Nokia 1830 PSS-8x platform, which is optimized for metro aggregation switching applications in optical transport networks1. In the exhibit, the number 1 refers to the Wavelength Router (WR8-88) block, as indicated by the label WR8-88AF. The other numbers refer to different components of the system, such as transponders, amplifiers, and switches. References: Nokia Optical Diagnostics and Troubleshooting Course, DWDM 1830 PSS-8 WR8-88AF Board

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