4A0-205 Nokia Optical Networking Fundamentals Questions and Answers

According to the Nokia Optical Networking documentation, a Shared Risk Group (SRG) is defined as "a set of network resources that share a common failure risk. When a resource in an SRG fails, the other resources in the group are also affected." This can include fibers, boards, nodes, and other network resources. The SRG concept is used in network design and protection mechanisms to ensure survivability and minimal impact on service in case of a failure.

The validate step in the EPT design process is used to trigger the run design action, which is responsible for verifying the consistency of the network design and fixing any errors that may exist. During the validation process, the system will compare the configuration available on the involved network elements and the design provided by EPT, and any discrepancies will be flagged for further investigation or correction.

Comprehensive and Detailed Explanation From Nokia Optical Networking Fundamentals:

In the Nokia 1830 PSS (Photonic Service Switch) architecture, theColorless Wavelength Router (CWR)is a specialized module used within ROADM nodes to enable "colorless" add/drop capabilities. Traditional static multiplexers, like the SFD (Static Filter Device), use fixed-wavelength ports where a specific port is hard-wired to a specific frequency (color). In contrast, a CWR allows any wavelength to be added or dropped from any of its ports.

The ports on a CWR arebi-directional. This means that a single physical port on the CWR card handles both the transmit (Tx) and receive (Rx) paths for a specific wavelength, typically connecting to a transponder's line-side interface. This bi-directional design simplifies fiber management within the shelf and is a key requirement for the "Colorless" attribute of modern flexible grids. By utilizing CWR modules, operators can remotely retune a transponder to a different frequency without needing a technician to physically move fiber patches to a different port on a multiplexer, significantly increasing operational efficiency and reducing human error during service provisioning or restoration.

The long-haul WT decoder parameter can be set in the NE parameters when designing a network with EPT. This parameter is used to adjust the sensitivity of the decoder and can help to improve the accuracy of the measurements for long-haul WTs.

The Network Element (NE) parameters in EPT (Element Planning Tool) are used to configure various settings and options for the network elements in the network. The long-haul WT decoder parameter is one such setting that can be configured in the NE parameters section. The user can access the NE parameters by navigating to the NE Parameters menu within the EPT interface. The user can then select the appropriate network element and modify the settings as needed. This information can be found in the Nokia guide for EPT.

Comprehensive and Detailed Explanation From Nokia Optical Networking Fundamentals:

In the context of optical networking fundamentals, anoptical switch(often referred to as a Photonic Switch or Layer 0 switch) is defined as a device that routes an optical signal—composed of photons—from an input port to one or more output ports without converting it into an electrical signal. This process is known astransparent switching. It operates entirely within the optical domain, maintaining the integrity of the lightwave regardless of the data rate or protocol being carried (e.g., SDH, Ethernet, or OTN).

It is important to distinguish this from Option D, which describes anElectrical or ODU Switch(Layer 1). In a device like the Nokia 1830 PSS-24x, signals are converted to electrical format (O-E-O) to be switched at the ODU (Optical Data Unit) level via a central fabric. While this provides "any-to-any" grooming, a trueoptical switch(like a WSS found in ROADMs) simply steers the light. The primary advantage of an optical switch is its ability to handle massive amounts of bandwidth with extremely low latency and lower power consumption compared to electrical switching, as it avoids the overhead of repeated O-E-O conversions at intermediate network nodes.

In optical fiber propagation context, the first, second, and third window refer to different wavelength intervals where the WDM (Wavelength Division Multiplexing) optical transmission occurs.

The first window is the lowest loss window and is typically in the range of 1300-1324nm. This is the most commonly used window for long-haul communications.

The second window is the 1550 nm window and is the most widely used window for long-haul and ultra-long-haul communications. This window has a lower attenuation than the first window, but it also has more dispersion, which can limit the maximum transmission distance.

The third window is the range of 1625-1675 nm, it is also called the L-band window. This window has lower attenuation than the first and second window but its usage is limited due to the high cost of equipment and lack of commercial devices.

These windows are used in WDM systems to increase the capacity of the fiber by transmitting multiple channels of data at different wavelengths on the same fiber.

A,C,D are not correct as they are not related to the meaning of first, second, and third window in the optical fiber propagation context.

Services are transported over trails; that is, services are clients with respect to trails. A service is a logical connection that is used to transport data from one point to another. It is created over a trail, which is a physical connection that is established by using multiple wavelengths. As such, services are clients with respect to trails, as they are transported over them.

Scattering and absorption are the main reasons for fiber attenuation. Scattering occurs when light bounces off the sides of the fiber, while absorption happens when light is absorbed by the glass or other materials that make up the fiber. Chromatic dispersion (CD) and polarization mode dispersion (PMD) are also factors that can cause attenuation, but they are not the main causes. Small channel spacing can also cause attenuation, but it is a secondary factor and is only significant in certain cases.

A degree-1 node is a node that only has one direction, and it is therefore a terminal node. This means that the node only has one input and one output port. It does not have any other ports to connect to other nodes or fibers. This is a common feature of some optical transport networks, such as ring networks, where a degree-1 node serves as the endpoint of the ring.

Yes, the user can apply manual changes but only for non-GMPLS nodes, as the control plane reserves node resources not editable by the user. The edit EPT menu allows the user to view information about a node but is not used to modify node parameters. The user can only apply manual changes to non-GMPLS nodes, as the control plane reserves node resources which cannot be modified by the user.

This is done in order to keep the NFM-T database in sync with the nodes in the network. The synchronization process allows the NFM-T to keep track of any changes that are made to the nodes, such as new nodes added, nodes removed, and so on. By synchronizing the node database with the NFM-T, network administrators can ensure that their network is up to date and running efficiently.

Comprehensive and Detailed Explanation From Nokia Optical Networking Fundamentals:

Performance Monitoring (PM) is critical for maintaining the health of a Nokia 1830 PSS network. The system collects data such as FEC corrected bits, optical power levels, and ODU-layer errors. According to Nokia's standard node management architecture, each data collection point (such as an optical port or an ODU termination point) stores a specific number of historical "bins" locally on the card or the shelf controller.

The standard storage capacity for these PM statistics is33 x 15-minute bins(covering the last 8 hours and 15 minutes of granular data) and8 x 1-day bins(covering the last week of daily totals). Additionally, there is1 raw binwhich contains the "current" accumulating data that has not yet been shifted into a completed 15-minute or 24-hour historical bin. This allows network operators usingWS-NOC(WaveSuite Network Operations Center) to retrieve recent historical performance data directly from the NE (Network Element) even if the management system was temporarily disconnected. If longer-term history is required, the management system must be configured to poll and archive these bins into its own database before they are overwritten on the hardware.

Node creation, systems validation and system provisioning. The CPB (Commissioning Parameter Builder) application is used to generate commissioning files for a Nokia 1830 Photonic Service Switch (PSS-1) and can be used to create new nodes, validate the system configuration, and provision the system with the appropriate settings and parameters. Power adjustment and generation of system loss report are not related to CPB.

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.