Networking Concepts (6)

Question 1

Which type of network connects local area networks (LANs) in distant locations?

WAN

LAN

MAN

Answer 1

WAN

WANs (wide area networks) connect LANs that are geographically distant. A LAN (local area network), as the name implies, is a group of computers, not other LANs, and it is contained within a small area. MANs (metropolitan area networks) connect LANs in a single metropolitan area; they are not confined to a small area. A MAN is typically larger than a LAN but smaller than a WAN. A campus area network (CAN) typically includes a group of adjacent buildings, such as those of a corporation or university

Question 2

Which of the following topologies requires the installation of terminating resistors at two locations?

Bus

Star

Ring

Answer 2

Bus

A bus topology requires terminating resistors at each end of the bus, to remove signals as they reach the end of the cable and prevent them from reflecting back in the other direction and interfering with newly transmitted signals

Question 3

A wireless access point (AP) enables computers equipped with wireless network interface adapters to function in which of the following topologies?

Ad hoc

Bus

Infrastructure

Answer 3

Infrastructure

A wireless access point is a device with a wireless transceiver that also connects to a standard cabled network. Wireless computers communicate with the access point, which forwards their transmissions over the network cable. This is called an infrastructure topology. A star or bus network requires the computers to be physically connected to the network cable, and an ad hoc topology is one in which wireless computers communicate directly with one another

Question 4

Which of the following topologies is used by the majority of new Ethernet networks installed today?

Virtual ring

Mesh

Hierarchical star

Answer 4

Hierarchical star

Virtually all of the new Ethernet networks installed today use the star or the hierarchical star topology, with one or more switches functioning as a cabling nexus

Question 5

Which of the following technologies associated with the Internet of Things (IoT) is often used to identify pets using embedded chips?

Z-wave

Bluetooth

RFID

Answer 5

RFID

Radio-frequency identification (RFID) uses tags containing data, frequently embedded in pets, which can be read using electromagnetic fields. Z-wave is a short-range wireless technology, frequently used for home automation. Bluetooth is a short-range wireless protocol, frequently used for computer peripherals and personal area networks (PANs). Near-field communication (NFC) provides wireless communication over ranges of 4 cm or less, and it is often used for payment systems

Question 6

Alice has constructed a five-node failover cluster in which all five servers are connected to a hard disk array using a dedicated Fibre Channel network. Which of the following terms describes this network arrangement?

SAN

PAN

WAN

Answer 6

SAN

A storage area network (SAN) is a network that is dedicated to carrying traffic between servers and storage devices. A personal area network (PAN) provides communication among devices associated with a single person, such as smartphones. A wide area network (WAN) is a network that connects devices or networks at different geographic locations. A metropolitan area network (MAN) is a type of WAN that connects devices within a limited geographic area

Question 7

Which of the following is not a technology typically used for a personal area network (PAN)?

Bluetooth

Z-Wave

ISDN

Answer 7

ISDN

Integrated Services Digital Network (ISDN) is a wide area networking technology that uses the telephone infrastructure to provide a high-speed dial-up service. It is therefore not suitable for use on a PAN. Bluetooth, Z-Wave, and near-field communication (NFC) are all short-range wireless technologies that are capable of proving communications between PAN devices

Question 8

Near-field communication (NFC) is a short-range wireless technology that is designed to facilitate communications between two devices within which of the following distances from each other?

4 millimeters

4 centimeters

4 decimeters

Answer 8

4 centimeters

NFC is designed to provide wireless communication between devices up to 4 cm apart, such as smartphones and payment systems

Question 9

Which of the following network topologies are used by wireless local area networks (WLANs)? (Choose all correct answers.)

Ad hoc

Bus

Infrastructure

Star

Answer 9

Ad hoc

Infrastructure

WLANs can use the ad hoc topology, in which devices communicate directly with each other, or the infrastructure topology, in which the wireless devices connect to an access point. The bus and star topologies are used by wired networks only

Question 10

Which of the following cabling topologies was used by the first Ethernet networks?

Bus

Ring

Star

Answer 10

Bus

The first Ethernet networks used a physical layer implementation commonly known as Thick Ethernet or 10Base5. The network used coaxial cable in a bus topology. Later Ethernet standards use twisted pair cable in a star topology. Ethernet has never used a ring or mesh topology

Question 11

On an Ethernet network using the star topology, which of the following devices can function as the cabling nexus that forms the figurative center of the star? (Choose all correct answers.)

Hub

Router

Switch

All of the above

Answer 11

Hub

Switch

A hub or a switch can function as the cabling nexus at the center of a star topology. Each of the devices on the network is connected by a cable to a hub or switch. Routers are used to connect networks to each other; they cannot function as the center of a star topology

Question 12

Which of the following topologies enables wireless devices to access resources on a wired network?

Ad hoc

Star

Infrastructure

Answer 12

Infrastructure

An infrastructure topology uses a wireless access point (AP) to connect wireless devices to a wired network. An ad hoc topology connects wireless devices to each other, without connecting to a wired network. The star and bus topologies do not support wireless devices

Question 13

Which of the following components are required for two computers to communicate using an IEEE 802.11 wireless LAN using an ad hoc topology?

A router connected to the Internet

A wireless access point

An external antenna

None of the above

Answer 13

None of the above

An ad hoc topology describes wireless computers that communicate directly with each other, without the need for any hardware other than their wireless network adapters. The ad hoc topology therefore does not require a router, an Internet connection, an access point, or a special antenna

Question 14

Which of the following is typically not an example of the Internet of Things (IoT)?

A key fob that unlocks your car

A smartphone home automation app

A remotely monitored cardiac pacemaker

Answer 14

A key fob that unlocks your car

A key fob that unlocks your car is typically a short-range radio or infrared (IR) device that does not use the Internet for its communications. Each of the other examples describes a device with an IP address that uses the Internet to communicate with a controller or monitoring station

Question 15

Which of the following topologies provides the greatest number of redundant paths through the network?

Star

Ring

Mesh

Answer 15

Mesh

A mesh topology is one in which every node is directly connected to every other node, therefore providing complete redundancy through the network. In a star topology, each node is connected to a central nexus, providing each with a single path to the rest of the network. In a ring topology, each node is connected to two other nodes, providing two possible paths through the network. In a bus topology, nodes are chained together in a line, providing no redundancy

Question 16

Which of the following Ethernet physical layer options does not use the star topology?

10Base2

10Base-T

100Base-TX

Answer 16

10Base2

10Base2 is the physical layer specification for Thin Ethernet, which uses coaxial cable in a bus topology. 10Base-T, 100Base-TX, and 1000Base-T all use twisted pair cable in a star topology

Question 17

Which of the following network types are typically wireless? (Choose all correct answers.)

WAN

PAN

SAN

WLAN

Answer 17

PAN

WLAN

Personal area networks (PANs) connect devices associated with a single person, such as smartphones, and are nearly always wireless. Wireless local area networks (WLANs) are wireless by definition. Wide area networks (WANs) typically span long distances and are typically wired, at least in part. Storage area networks (SAN) require high performance levels and are nearly always wired

Question 18

In its physical implementation, a LAN using a logical ring topology most closely resembles which of the following physical topologies?

Bus

Mesh

Star

Answer 18

Star

In a logical ring topology, the signal path leads from each node to the next one, but physically, the network resembles a star, with each node connected to a central nexus. Signals travel from one node to the nexus, then to the next node, and then back to the nexus, and so on. A logical ring could not be implemented on a physical bus topology. A mesh topology could conceivably host a logical ring, but this would be highly impractical on a LAN. Ad hoc is a wireless topology that is not applicable in this situation

Question 19

Which of the following wireless networking technologies will never experience interference from a 2.4 GHz wireless telephone? (Choose all correct answers.)

IEEE 802.11a

IEEE 802.11b

IEEE 802.11g

IEEE 802.11n

IEEE 802.11ac

Answer 19

IEEE 802.11a

IEEE 802.11ac

IEEE 802.11b, 802.11g, and 802.11n networks all can use the 2.4 GHz frequency band for their transmissions, which can experience interference from a wireless telephone using the same frequency. IEEE 802.11a and IEEE 802.11ac, however, use the 5 GHz band, which will not experience interference from a 2.4 GHz phone

Question 20

Which of the following wireless networking standards is capable of supporting speeds of 54 Mbps and is also backward compatible with IEEE 802.11b?

IEEE 802.11a

IEEE 802.11 g

IEEE 802.11n

Answer 20

IEEE 802.11 g

IEEE 802.11g supports transmission speeds up to 54 Mbps, and it is backward compatible with 802.11b equipment. IEEE 802.11 cannot run at 54 Mbps, and while 802.11a can, it is not compatible with 802.11b. IEEE 802.11n cannot run at 54 Mbps, though it can run at faster speeds. Bluetooth is not compatible with any of the IEEE 802.11 standards

Question 21

Which of the following wireless LAN standards include the ability to use multiple input and multiple output (MIMO) antennae? (Choose all correct answers.)

IEEE 802.11a

IEEE 802.11b/g

IEEE 802.11n

IEEE 802.11ac

Answer 21

IEEE 802.11n

IEEE 802.11ac

Both the IEEE 802.11n and 802.11ac standards include MIMO, which enables them to effectively multiplex signals using multiple antennae. This capability was first introduced in the 802.11n standard, so the 802.11a and 802.11b/g standards do not support it

Question 22

Which of the following is a cellular communication technology that is virtually obsolete in the United States?

CDMA

CSMA/CD

TDMA

Answer 22

TDMA

Time Division Multiple Access (TDMA) is a communication technique that splits a frequency into multiple time slots, enabling it to carry multiple data streams. Commonly used in 2G cellular systems, the major U.S. carriers no longer use it in their 3G systems. Code Division Multiple Access (CDMA) and Global System for Mobile Communication (GSM) are alternative communications techniques that are currently used by the major U.S. cellular carriers. Carrier Sense Multiple Access with Collision Detection (CSMA/CD) is a media access control method used by Ethernet networks; it is not a cellular communication technology

Question 23

Which of the following IEEE wireless LAN standards uses the Direct Sequence Spread Spectrum (DSSS) signal modulation technique?

802. 11a
803. 11b
804. 11 g

Answer 23

802.11b

The IEEE 802.11b standard calls for DSSS signal modulation. All of the other standards listed call for Orthogonal Frequency-Division Multiplexing (OFDM) encoding

Question 24

When designing a wireless LAN installation, which of the following are valid reasons to install a unidirectional antenna in an access point, rather than an omnidirectional one? (Choose all correct answers.)

The access point will be located against an outside wall.

There are many interior walls between the access point and the most distant workstation.

A unidirectional antenna can be focused to a specific signal pattern width.

All of the above.

Answer 24

All of the above.

By placing a unidirectional antenna against an outside wall, you can limit network access to users inside the structure. Unidirectional antennae provide greater signal strength than omnidirectional antennae, enabling their signals to penetrate more interior walls. It is possible to focus a unidirectional antenna to a wider or narrower signal pattern

Question 25

How do wireless networking devices conforming to the IEEE 802.11n and 802.11ac standards achieve transmission speeds greater than 72.2 Mbps?

By using direct sequence spread spectrum (DSSS) modulation

By using multiple antennae to transmit several data streams simultaneously

By using frequencies in the 5 GHz band

Answer 25

By using multiple antennae to transmit several data streams simultaneously

The IEEE 802.11n and 802.11ac standards support a transmission technique called multiple input and multiple output (MIMO), which combines the bandwidth of multiple data streams to achieve greater throughput. IEEE 802.11n and 802.11ac do use the 5 GHz band, but this in itself does not yield greater transmission speeds. The specified standards do not call for the use of DSSS modulation, nor do they sacrifice range for speed. In fact, 802.11n and 802.11ac networks can achieve greater ranges than the previous technologies