N10-009 Practice Test 29 — 15 Questions

Question 1

A network engineer needs to connect two network segments that use different physical media: one segment uses copper Ethernet and the other uses fiber optic. The device must forward frames based on MAC addresses and must not perform any routing. Which device should the engineer choose?

Accepted Answer

Bridge. A bridge operates at Layer 2, forwarding frames based on MAC addresses while connecting different physical media (e.g., copper to fiber). It does not perform routing, making it the correct choice for this scenario. Unlike a media converter, a bridge also provides segmentation and collision domain isolation.

Answer

Layer 3 switch

Answer

Media converter

Answer

Router

Question 2

A network has a single switch with VLANs 10, 20, and 30 configured. The switch is connected to a router that has three subinterfaces, each in a different VLAN. How many broadcast domains are present?

Accepted Answer

3. Each VLAN is a separate Layer 2 broadcast domain. With VLANs 10, 20, and 30 configured on the switch and a router using subinterfaces to route between them, there are exactly three broadcast domains — one per VLAN. Broadcasts are confined to their VLAN and do not cross VLAN boundaries without a Layer 3 device.

Answer

1

Answer

4

Answer

5

Question 3

A network engineer is reviewing RFC 1918 address ranges to plan a private IP addressing scheme. Which of the following IP addresses falls within the private address space for Class A?

Accepted Answer

10.10.10.1. Option C is correct because RFC 1918 defines the Class A private address range as 10.0.0.0/8, which includes all addresses from 10.0.0.0 to 10.255.255.255. 10.10.10.1 falls within this range, making it a valid private IP address for internal network use.

Answer

172.16.0.1

Answer

192.168.1.1

Answer

172.32.0.1

Question 4

A network engineer is designing a subnet to accommodate 50 devices in a single broadcast domain. The engineer uses a /26 subnet mask. How many usable host addresses are available?

Accepted Answer

62. A /26 subnet mask provides 2^(32-26) = 64 total addresses. Subtracting the network and broadcast addresses leaves 62 usable host addresses. This is sufficient for 50 devices in a single broadcast domain.

Answer

30

Answer

126

Answer

254

Question 5

A network engineer needs to connect two switches that are located 450 meters apart. Which combination of fiber optic transceiver and cable type would support the highest data rate over this distance?

Accepted Answer

10GBASE-LR with single-mode fiber. 10GBASE-LR (Long Reach) supports 10 Gbps over single-mode fiber (SMF) up to 10 km, easily covering the 450-meter distance. Single-mode fiber has a smaller core (9 µm) that minimizes modal dispersion, enabling higher data rates over longer distances compared to multimode fiber. This combination provides the highest data rate (10 Gbps) among the options for the given distance.

Answer

10GBASE-SR with multimode fiber

Answer

1000BASE-LX with single-mode fiber

Answer

1000BASE-SX with multimode fiber

Question 6

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

Accepted Answer

It identifies which part of an IP address is the network address and which part is the host address. The subnet mask is a 32-bit value that separates the IP address into network and host portions through a bitwise AND operation. This allows routers and hosts to determine whether a destination IP is on the same local network or requires forwarding to a default gateway. Without the subnet mask, a device cannot distinguish the network prefix from the host identifier, making routing impossible.

Answer

It dynamically assigns IP addresses to devices on the network

Answer

It encrypts data packets to ensure secure communication

Answer

It specifies the IP address of the router that forwards traffic to other networks

Question 7

A network technician is explaining the difference between TCP and UDP to a junior technician. Which of the following correctly identifies a characteristic of TCP but NOT of UDP?

Accepted Answer

It uses a three-way handshake to establish a connection before data transfer.. TCP is a connection-oriented protocol that uses a three-way handshake (SYN, SYN-ACK, ACK) to establish a reliable connection before any data is transmitted, ensuring ordered delivery and error recovery. UDP, in contrast, is connectionless and sends datagrams without any prior setup, making the three-way handshake a defining characteristic of TCP only.

Answer

It provides connectionless communication with minimal overhead.

Answer

It supports multicast and broadcast transmissions.

Answer

It is commonly used for real-time applications like VoIP and video streaming.

Question 8

A network technician installs a new 802.3at (PoE+) access point in a warehouse. The AP is connected via a 200-foot Cat5e cable to a switch that only supports 802.3af (PoE). The AP powers on but experiences intermittent connectivity drops. What is the most likely cause?

Accepted Answer

The AP is not receiving enough power from the switch. The switch only supports 802.3af (PoE), which provides a maximum of 15.4 watts per port, while the 802.3at (PoE+) access point requires up to 25.5 watts to operate reliably. The AP powers on because it can negotiate 802.3af power, but under load (e.g., transmitting at higher power or using multiple radios), it draws more current than the switch can supply, causing voltage droop and intermittent resets or link drops. This is a classic power budget mismatch scenario.

Answer

The cable length exceeds the maximum allowed for PoE

Answer

Duplex mismatch between the AP and the switch

Answer

Radio frequency interference from warehouse equipment

Question 9

A network engineer needs to connect two devices that are 150 meters apart with a 10 Gbps link. Which cabling type is most suitable?

Accepted Answer

Single-mode fiber. Single-mode fiber (SMF) is the correct choice because it supports 10 Gbps transmission over distances well beyond 150 meters, typically up to 10 km or more using 10GBASE-LR optics. In contrast, copper cabling like Cat6a or Cat7 is limited to 100 meters for 10GBASE-T, and multimode fiber (MMF) with 10GBASE-SR is limited to about 300-400 meters depending on the fiber grade (e.g., OM3/OM4), but SMF provides the most reliable and future-proof solution for this distance.

Answer

Cat6a UTP

Answer

Cat7 STP

Answer

Multimode fiber

Question 10

A network engineer needs to configure a trunk link between two Cisco switches so that only VLANs 10, 20, and 30 are allowed. Which command set will accomplish this?

Accepted Answer

switchport trunk allowed vlan 10,20,30. Option A is correct because the 'switchport trunk allowed vlan' command explicitly defines which VLANs are permitted to traverse the trunk link. By specifying '10,20,30', only traffic from those VLANs is forwarded, while all other VLANs are pruned from the trunk. This is the standard method for restricting VLANs on an IEEE 802.1Q trunk between Cisco switches.

Answer

switchport mode trunk

Answer

switchport trunk native vlan 1

Answer

switchport trunk encapsulation dot1q

Question 11

A network engineer needs to implement a wireless network in a large open-plan office with high client density. The network must provide the fastest possible speeds and efficient handling of many simultaneous connections. Which IEEE 802.11 standard should be used?

Accepted Answer

802.11ax. 802.11ax (Wi-Fi 6) is the correct choice because it introduces Orthogonal Frequency Division Multiple Access (OFDMA) and MU-MIMO (both uplink and downlink), which significantly improve spectral efficiency and capacity in high-density environments. It also supports 1024-QAM modulation for higher data rates, making it ideal for an open-plan office with many simultaneous connections.

Answer

802.11ac

Answer

802.11n

Answer

802.11r

Question 12

A network technician needs to connect two switches to support multiple VLANs between them. The technician wants to use a single link to carry traffic for all VLANs. Which protocol should be used to tag frames with VLAN information?

Accepted Answer

802.1Q. 802.1Q is the IEEE standard for VLAN tagging, which inserts a 4-byte tag into the Ethernet frame header to identify the VLAN membership of the frame. This allows a single trunk link between two switches to carry traffic for multiple VLANs by tagging each frame with its corresponding VLAN ID (1-4094).

Answer

802.1X

Answer

802.11

Answer

802.3

Question 13

A network technician is troubleshooting a workstation that intermittently loses network connectivity. The link LED on the switch port is blinking slowly. The technician checks the cable and it appears fine. Which of the following is the most likely cause?

Accepted Answer

Duplex mismatch. A slow-blinking link LED on a switch port typically indicates a duplex mismatch, where one device is set to full duplex and the other to half duplex. This causes frame collisions and CRC errors, leading to intermittent connectivity even though the cable appears fine. The symptom of intermittent loss with a physically good cable is classic for duplex mismatch, as the port is still electrically connected but suffers from excessive retransmissions.

Answer

Incorrect VLAN assignment

Answer

Bad cable

Answer

Spanning Tree blocking

Question 14

A network technician is explaining network segmentation to a junior technician. Which of the following devices increases the number of collision domains but does not increase the number of broadcast domains?

Accepted Answer

Switch. A switch creates a separate collision domain for each port, so multiple devices can transmit simultaneously without collisions, but it does not segment broadcast domains; all ports remain in the same broadcast domain unless VLANs are configured. This directly matches the question's requirement: increasing collision domains without increasing broadcast domains.

Answer

Hub

Answer

Router

Answer

Repeater

Question 15

A network technician needs to capture and analyze packets on a specific network segment to identify the source of a performance slowdown. Which tool is best suited for this task?

Accepted Answer

Protocol analyzer (e.g., Wireshark). A protocol analyzer like Wireshark is the correct tool because it captures and decodes packets at the data-link layer, allowing the technician to inspect frame headers, IP addresses, TCP/UDP ports, and payload contents on a specific network segment. This deep packet inspection is essential for identifying the root cause of performance slowdowns, such as excessive retransmissions, high latency, or application-layer issues. Unlike other tools, a protocol analyzer provides granular visibility into traffic patterns and protocol behavior.

Answer

Port scanner (e.g., Nmap)

Answer

Ping

Answer

Traceroute