Nokia 4A0-F10 Exam Questions Instant Access

Question 1

A residential gateway ONT provides routed Internet access to devices in a subscriber's home. Which DHCP role does it normally perform on the home LAN?

AIt acts as a DHCP server and assigns private IP addresses to home devices.

BIt acts only as a DHCP relay and never maintains address information.

CIt acts as a DHCP client for every device connected to the LAN.

DIt disables local addressing and assigns public addresses directly from the OLT.

Answer : A

A Layer 3 residential gateway normally operates as a DHCP server on the subscriber's home LAN. It assigns private IP addresses and other configuration information, such as the default gateway and DNS server addresses, to connected devices. On its network-facing WAN interface, the gateway may operate as a DHCP client to obtain service parameters from the operator's network. These two DHCP roles must not be confused. The gateway also commonly performs routing, Network Address Translation, firewall enforcement, and local Ethernet or Wi-Fi connectivity. The OLT transports and controls subscriber access traffic but does not normally allocate private LAN addresses directly to individual home devices. This architecture separates the operator-facing connection from the subscriber's private local network and allows multiple home devices to share the broadband service.

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Question 2

Which characteristic distinguishes G.fast from traditional ADSL technologies?

AG.fast operates only over passive optical splitters.

BG.fast commonly uses high frequencies and time-division duplexing over short copper loops.

CG.fast requires a separate copper pair for upstream and downstream traffic.

DG.fast carries only voice services and does not support broadband data.

Gfast is designed to deliver high broadband rates over relatively short copper loops, frequently using existing building or drop wiring. It uses a much wider and higher-frequency spectrum than traditional ADSL and commonly employs Time Division Duplexing. With TDD, upstream and downstream transmission use the same frequency spectrum during different time intervals. The upstream-to-downstream capacity ratio can therefore be adjusted through the TDD configuration. Higher frequencies can support greater capacity but experience substantial attenuation over distance, which is why G.fast is best suited to short loops. It does not operate through passive optical splitters, although fiber may be deployed close to the subscriber before the final copper segment. G.fast also supports broadband services rather than voice-only delivery.
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Answer : B

Question 3

Which of the following statements correctly distinguishes traffic shaping from traffic policing?

AShaping buffers excess traffic, while policing can drop or remark nonconforming traffic.

BShaping always drops excess traffic immediately, while policing delays it in a queue.

CShaping selects multicast groups, while policing assigns subscriber VLANs.

DShaping is applied only to optical signals, while policing is applied only to copper signals.

Answer : A

Traffic shaping regulates an outgoing traffic stream by buffering packets that temporarily exceed the configured rate and transmitting them later. This smooths bursts but can introduce additional latency because packets remain in a queue. Traffic policing checks traffic against configured rate limits without normally delaying nonconforming packets. Depending on the policy, packets exceeding the permitted profile can be dropped or marked with a lower priority. Both mechanisms are QoS tools and are independent of whether the physical access medium is fiber, copper, or wireless. They also do not control multicast membership or VLAN assignment. In a fixed-access network, shaping can help produce a smoother egress rate, while policing can enforce subscriber or service bandwidth limits at an ingress boundary.

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Question 4

A YANG model specifies that a configuration leaf can contain an integer from 1 through 4094. What is the principal benefit of this restriction?

AIt allows invalid values to be corrected automatically by the optical splitter.

BIt enables configuration values to be validated against the defined data model.

CIt converts the integer into an Ethernet frame.

DIt prevents the leaf from being accessed through NETCONF.

Answer : B

YANG can define data types, ranges, patterns, mandatory nodes, default values, and relationships between configuration elements. A range restriction allows management software and network devices to verify that a submitted value falls within the permitted limits. For example, restricting a VLAN-related integer to an appropriate range prevents clearly invalid values from being accepted. This model-driven validation reduces configuration errors and makes automation more predictable. A passive optical splitter has no processing capability and cannot correct invalid configuration. The restriction also does not convert a value into an Ethernet frame or prevent NETCONF access. Instead, NETCONF can carry configuration data structured according to the YANG model, and the server can reject an <edit-config> request when the proposed data violates applicable schema constraints.

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Question 5

What is a principal responsibility of the NFV Orchestrator in an NFV environment?

ACoordinating network-service lifecycle activities and virtualized resources

BConverting GPON optical signals into subscriber Ethernet signals

CAssigning Wi-Fi channels independently on every home device

DPerforming physical fiber splicing in the outside plant

Answer : A

The NFV Orchestrator coordinates the lifecycle of network services composed of one or more virtualized network functions and helps coordinate the infrastructure resources required by those services. It can work with Virtual Network Functions Managers and Virtualized Infrastructure Managers during service instantiation, scaling, modification, and termination. The VNFM focuses on the lifecycle of VNF instances, while the VIM manages virtualized compute, storage, and networking resources. The NFV Orchestrator does not terminate GPON optical signals, manage individual home Wi-Fi radio channels as its primary function, or perform physical fiber installation. Its higher-level coordination role helps translate a network-service definition into the deployment and resource actions necessary to create and maintain that service within the virtualized environment.

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Question 6

Which component of a typical Optical Distribution Network requires no electrical power to perform its primary function?

AOptical line termination

BPassive optical splitter

CResidential gateway

DOptical network termination

Answer : B

A passive optical splitter divides an incoming optical signal into multiple output paths without requiring electrical power. It is a fundamental component of the Optical Distribution Network connecting an OLT to multiple ONTs or ONUs. The splitter does not regenerate, amplify, or actively switch the optical signal. Consequently, splitting introduces optical loss that must be considered when calculating the PON power budget. The OLT and ONT are active devices because they require power to transmit, receive, process, and convert signals. A residential gateway also requires power to provide functions such as routing, firewall enforcement, DHCP, Ethernet switching, and Wi-Fi connectivity. The use of passive splitters reduces the need for powered equipment in the outside plant, which can simplify field maintenance and lower operational costs.

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Question 7

Which YANG node type represents multiple scalar values under the same node name without allowing child nodes?

AContainer

BList

CLeaf-list

DChoice

Answer : C

A YANG leaf-list represents a sequence of scalar values of the same defined type. Like a leaf, each value is terminal and cannot contain child nodes. However, unlike a single leaf, a leaf-list can have multiple entries. A YANG list also supports multiple instances, but each list entry can contain child nodes and is normally identified by one or more key leaves. A container groups related child nodes but does not itself represent a repeated collection of scalar values. A choice defines alternative branches in a data model, allowing one set of nodes from the available cases to be selected. Correctly distinguishing these node types is important when interpreting YANG schemas used to configure and monitor access devices through model-driven management interfaces.

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Nokia Fixed Networks Fundamentals 4A0-F10 Exam Questions