N10-009 Networking Concepts Practice Test 3 — 15 Questions

Question 1

A network engineer is troubleshooting connectivity issues between two data center switches that are configured to support jumbo frames with an MTU of 9000. The link is a 10 Gigabit Ethernet fiber connection. Large file transfers fail, but small transfers succeed. What is the most likely cause?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

C. The most likely cause is that an intermediate device (such as a router or another switch) along the Layer 2 path is not configured for jumbo frames and has a standard MTU of 1500. Since both end switches support an MTU of 9000, large frames are sent but are dropped when they reach the intermediate device that cannot handle them. Small frames (≤1500 bytes) pass through successfully because they fit within the standard MTU.

Answer

A

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B

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D

Question 2

Which of the following best describes the function of a default gateway?

Accepted Answer

It routes packets from a local subnet to destinations on other networks.. The default gateway is a router or Layer 3 device on a local subnet that serves as the next-hop IP address for packets destined to networks outside the local subnet. When a host determines that the destination IP is not on the same subnet (using its subnet mask), it forwards the packet to the default gateway's MAC address via ARP, which then routes the packet toward the remote network. Without a correctly configured default gateway, a host can only communicate within its own subnet.

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It translates private IP addresses to public IP addresses.

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It provides DHCP services to clients.

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It performs DNS resolution for network clients.

Question 3

A network switch is experiencing a high number of collisions on a specific port. The connected device is configured for half-duplex. Which of the following is the most likely cause?

Accepted Answer

The switch port is configured for full-duplex. When a switch port is configured for full-duplex but the connected device operates in half-duplex, a duplex mismatch occurs. The switch transmits without checking for collisions (as full-duplex does not use CSMA/CD), while the half-duplex device expects to sense the carrier before sending, leading to collisions on the port. This is the most common cause of excessive collisions on a single switch port.

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The cable length exceeds 100 meters

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The device is using an incorrect VLAN

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The switch port is configured for 1000BASE-T but the device only supports 100BASE-TX

Question 4

A router has two routes to the same destination network: one learned via OSPF with a metric of 10, and another learned via EIGRP with a composite metric of 3072. The default administrative distances are OSPF=110, EIGRP=90. Which route will be installed in the routing table?

Accepted Answer

The EIGRP route because it has a lower administrative distance. The EIGRP route is installed because administrative distance (AD) is the primary tiebreaker when multiple routing protocols provide routes to the same destination. EIGRP has a default AD of 90, which is lower than OSPF's AD of 110, so the router prefers the EIGRP route regardless of metric values. Metrics are only compared when routes come from the same protocol.

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The OSPF route because it has a lower metric

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Both routes will be installed for load balancing

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The OSPF route because it is a link-state protocol

Question 5

A network engineer wants to segment a LAN into multiple broadcast domains without purchasing additional hardware. Which of the following technologies should be implemented?

Accepted Answer

VLANs. VLANs (Virtual Local Area Networks) allow a network engineer to logically segment a single physical LAN switch into multiple isolated broadcast domains without purchasing additional hardware. By assigning switch ports to different VLAN IDs, broadcast traffic is confined to ports within the same VLAN, effectively creating separate Layer 2 networks on the same switch infrastructure.

Answer

Subnetting

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VPN

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NAT

Question 6

A network administrator needs to ensure that data sent from a host arrives at the correct destination on a different network. Which of the following provides the logical address used for this purpose in IPv4?

Accepted Answer

IP address. In IPv4, the logical address used to route data between different networks is the IP address. The IP address contains a network portion that routers use to forward packets across network boundaries, ensuring the data reaches the correct destination network and host.

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MAC address

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Port number

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Default gateway

Question 7

A network technician is configuring a small office network with two subnets: 10.0.1.0/24 and 10.0.2.0/24. Each subnet has its own switch, and both switches are connected to a router with interfaces 10.0.1.1 and 10.0.2.1. Hosts on subnet A can ping the router's interface in their subnet but cannot ping hosts on subnet B. Which of the following is the most likely cause?

Accepted Answer

IP routing is disabled on the router.. The hosts on subnet A can ping their default gateway (10.0.1.1) but cannot reach hosts on subnet B, which indicates that the router is not forwarding packets between the two directly connected subnets. This behavior is characteristic of a router with IP routing disabled, as the router will not perform inter-VLAN or inter-subnet forwarding unless the 'ip routing' command is enabled globally. Without IP routing, the router acts as a host and will only respond to traffic destined for its own interfaces, dropping any packets that require forwarding to another subnet.

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The router is not configured with a routing protocol.

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The hosts in subnet A have the wrong default gateway.

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The switch in subnet A is blocking ICMP traffic.

Question 8

Which of the following is the primary function of a subnet mask in IPv4 networking?

Accepted Answer

It determines the network portion of an IP address. The subnet mask's primary function is to distinguish the network portion from the host portion of an IPv4 address. By applying a bitwise AND operation between the IP address and the subnet mask, the network address is derived, which is essential for routing decisions. Without this separation, devices cannot determine whether a destination is local or requires forwarding through a router.

Answer

It identifies the default gateway for a subnet

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It provides encryption for data in transit

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It maps IP addresses to MAC addresses

Question 9

Which of the following uniquely identifies a hardware network interface on a device?

Accepted Answer

MAC address. A MAC (Media Access Control) address is a hardware-embedded, globally unique identifier assigned to a network interface controller (NIC) by the manufacturer. It operates at Layer 2 (Data Link Layer) of the OSI model and is used for local network communication, ensuring that no two devices on the same broadcast domain have the same MAC address.

Answer

IP address

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Subnet mask

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Default gateway

Question 10

At which layer of the OSI model does a network device encapsulate data into frames and add source and destination MAC addresses?

Accepted Answer

Layer 2 – Data Link. The Data Link layer (Layer 2) is responsible for node-to-node communication and encapsulates packets from the Network layer into frames. It adds a header containing the source and destination MAC addresses, which are used for delivery within the same local network segment. This process is defined by IEEE 802 standards such as Ethernet (802.3) and Wi-Fi (802.11).

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Layer 1 – Physical

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Layer 3 – Network

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Layer 4 – Transport

Question 11

Which protocol is used to resolve a known IP address to a corresponding MAC address on a local network?

Accepted Answer

ARP. ARP (Address Resolution Protocol) is used to resolve a known IP address to its corresponding MAC address on a local network. When a host needs to send a frame to another host on the same subnet, it broadcasts an ARP request containing the target IP; the host with that IP responds with its MAC address, which is then cached for future use.

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DNS

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DHCP

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ICMP

Question 12

Which of the following is a characteristic of a Layer 2 network switch?

Accepted Answer

Uses MAC addresses to make forwarding decisions. A Layer 2 network switch operates at the Data Link layer of the OSI model and uses MAC addresses to make forwarding decisions. It examines the destination MAC address in an Ethernet frame and consults its MAC address table to determine the appropriate port to forward the frame, enabling efficient local area network communication.

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Makes forwarding decisions based on IP addresses

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Can route traffic between different VLANs without a router

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Provides Network Address Translation (NAT)

Question 13

Which layer of the OSI model is responsible for logical addressing and routing of packets between networks?

Accepted Answer

Network layer. The Network layer (Layer 3) is responsible for logical addressing (e.g., IPv4/IPv6 addresses) and routing packets between different networks by determining the best path using routing protocols such as OSPF, BGP, or static routes. Unlike the Data Link layer, which handles physical addressing (MAC) within a single network segment, the Network layer enables end-to-end delivery across multiple hops.

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Data Link layer

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Transport layer

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Application layer

Question 14

Which of the following IP addresses is a private IP address as defined by RFC 1918?

Accepted Answer

192.168.1.1. (192.168.1.1) is correct because RFC 1918 reserves the 192.168.0.0/16 block (192.168.0.0 – 192.168.255.255) for private use within local networks. This address is not routable on the public internet, making it suitable for internal LAN addressing.

Answer

169.254.1.1

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172.32.1.1

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172.15.1.1

Question 15

In a network, a collision domain is a network segment where which of the following is true?

Accepted Answer

A: Only one device can transmit at a time to avoid data collisions. In a collision domain, only one device can transmit at a time because if two or more devices transmit simultaneously, their signals collide, corrupting the data. This is a fundamental characteristic of half-duplex Ethernet segments, such as those using hubs or legacy bus topologies, where the medium is shared and CSMA/CD (Carrier Sense Multiple Access with Collision Detection) is used to manage access.

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B: All devices share the same IP subnet

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C: Broadcast traffic is confined to that segment

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D: MAC addresses are resolved to IP addresses