Free Nokia 4A0-205 Practice Exam with Questions & Answers

Comprehensive and Detailed Explanation From Nokia Optical Networking Fundamentals:

In the context of the Nokia 1830 PSS (Photonic Service Switch) and general WDM principles, the statement that OADMsalwaysrequire O-E-O (Optical-Electrical-Optical) conversion for pass-through channels is fundamentally incorrect. The primary purpose of anOADMis to provide the ability to "add" or "drop" specific wavelengths while allowing other wavelengths (known as express or pass-through channels) to continue through the node entirely in thephotonic domain.

By remaining in the optical layer, these express channels avoid the latency and cost associated with O-E-O conversion.FOADMs(Fixed OADMs) use static filters to achieve this, whileROADMs(Reconfigurable OADMs) use Wavelength Selective Switches (WSS) to dynamically route traffic. O-E-O conversion only occurs at thetransponderormuxponderlevel when a service is terminated (dropped) or initiated (added) to convert the client signal into a compliant DWDM wavelength. Therefore, the efficiency of an optical network relies on the fact that pass-through traffic stays as light, bypassing the need for electrical processing at every node.

Comprehensive and Detailed Explanation From Nokia Optical Networking Fundamentals:

In theOptical Transport Network (OTN)hierarchy, theODUk (Optical Data Unit of order k)is the fundamental unit for electronic grooming and switching. Unlike the OTUk layer, which is tied to a specific physical optical interface and includes theForward Error Correction (FEC), the ODUk layer is "path-oriented." This means that in a switched WDM system like the Nokia 1830 PSS-24x, the ODUk containers can be switched across a backplane from one line card to another without needing to deconstruct the entire optical signal.

To clarify the other options:Option Ais false because FEC is part of theOTUk(Transport Unit) layer.Option Cis false because ODUk processing is entirelyelectrical(O-E-O must occur to access the ODUk overhead).Option Dis false because theOPU (Optical Payload Unit)is actually the "first" container where the client signal is mapped; the ODUk then wraps around the OPU to add path-level monitoring and maintenance signals. Therefore, the ODUk acts as the "virtual container" that allows the network to manage services end-to-end across multiple optical spans.

The CPB (Commissioning Parameter Builder) application is used to generate the commissioning files for a Nokia 1830 Photonic Service Switch (PSS-1). The CPB application allows the user to create multiple commissioning files [1][2], which can be used to configure a variety of different features on the device. The CPB also allows users to view, edit and modify the commissioning files before they are uploaded to the device. The NSP (Network Service Platform) and EPT (Element Provisioning Tool) are used to manage the devices and network elements within the network, but do not generate commissioning files.

Comprehensive and Detailed Explanation From Nokia Optical Networking Fundamentals:

The Nokia 1830 PSS uses a Command Line Interface (CLI) that is distinct from the Nokia SR-OS used in routers. For technicians performing local maintenance or troubleshooting via a serial or SSH connection to theShelf Controller (EC), the command to view the current status of the network element's alarms isshow fault-databaseor the shorthandalm.

When the alm command is executed, the system displays a table containing all active alarms, their severity (Critical, Major, Minor, or Warning), the timestamp of the occurrence, and the specific object (e.g., a specific port or card) that is reporting the fault. This is the primary method for "Layer 0" local troubleshooting. While management software likeWS-NOCprovides a Graphical User Interface (GUI) to view these alarms, knowing the CLI command is essential for field operations where a connection to the central management system might not be available. Option B, C, and D are incorrect as they do not follow the specific syntax of the 1830 PSS CLI environment.

The EPT run design command can remove previously designed elements, but the user is prompted to choose whether to delete them or leave them intact. This allows the user to progress their design while still keeping the existing elements in place. If the user selects to leave the existing elements, then they will remain in the same slots. If GMPLS nodes are used, the existing slots cannot change as they are controlled by another manager (GMRE).

Tracking the protection path for a specific wavelength. The Wavelength Tracker tool is used to track the protection path of a specific wavelength, allowing the user to quickly identify any issues that may arise and take corrective action.

Wavelength Tracker tool is a feature used to monitor and track the protection path for a specific wavelength in an optical network. It can also be used to monitor and verify the working state of the protection path, and to detect and troubleshoot protection switch events. The Wavelength Tracker tool can be used to monitor the protection path for a specific wavelength, and it can also be used to trace the end-to-end path of a wavelength through the network. This tool is typically used by network operators to monitor and troubleshoot wavelength-level issues in the network, such as protection switch events or wavelength-level performance issues.

The OSNR is defined as the ratio between the average optical signal power and the average optical noise power over a specific spectral bandwidth. This is also known as the signal-to-noise ratio (SNR), and it is a measure of how much signal is present in the optical signal compared to the noise, usually expressed in decibels (dB).

In Raman amplification, a pump laser is used to excite the Raman-active molecules in the fiber, which then amplifies the signal light as it travels in the opposite direction. In the 1830 specific implementation, the pump laser is typically a high-power laser that is launched into the fiber in the opposite direction to the signal. The pump light interacts with the Raman-active molecules in the fiber, which then amplifies the signal light as it travels in the opposite direction. This allows the Raman pump to provide a gain that increases with distance, which can be used to compensate for the loss of signal power as it travels through the fiber.

The GMRE activation status is reported in the supervision state column on the node list. The supervision state column displays the GMRE status of the node, which is either "Activated" or "Not Activated". This allows the user to quickly check the GMRE activation status of a node without having to ping the node from the NFM-T platform.

A trail is a transparent transport of a client signal. A trail is a physical link between two points in an optical network, allowing for the transport of a client signal from one point to the other. It is a low-order signal, such as a 10G Ethernet or a Fibre Channel signal, encapsulated into a high-order container, such as a 40G or 100G signal. This allows for the transport of the client signal over longer distances, increasing the power budget of the optical link.