Chapter 12: Wireless Networking Flashcards

1
Q

how is data passed in wireless communication systems

A

they modulate data onto electromagnetic signals like radio and light waves

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2
Q

higher frequency carries … data over a … distance with … susceptibility to interference

A

carries more data but over a shorter distance and with more susceptibility to interference

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3
Q

Wireless communication systems use … as a medium access control protocol

A

CSMA/CA

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4
Q

CSMA/CA

A

carrier sense multiple access with collision avoidance

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5
Q

MAC

A

medium access control protocol

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6
Q

radio frequency band

A

a subset of the radio spectrum designated for a specific use

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7
Q

Wi-Fi systems operate in the … GHz bands

A

2.4-GHz and 5-GHz bands

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8
Q

Wireless communications systems use one of two modulation techniques

A

spread spectrum or orthogonal frequency division multiplexing

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9
Q

OFDM

A

orthogonal frequency division multiplexing

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10
Q

Spread spectrum modulation techniques include …

A

frequency hopping spread spectrum and direct sequence spread spectrum

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11
Q

FHSS

A

frequency hopping spread spectrum

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12
Q

DSSS

A

direct sequence spread spectrum

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13
Q

DSSS

A

spreads the data being transmitted over a wider spectrum than normally needed to overcome interference; relies on a chip sequence to let receiving stations know how to reconstruct the transmitted data

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14
Q

FHSS uses ….

A

uses a single subchannel at a time, but rapidly changes channels in a particular hope sequence

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15
Q

WLANs

A

Wireless local area networks

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16
Q

two forms of WLANs

A

infrastructure and ad hoc

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17
Q

Environments segmented into different WLANs by using …

A

using different SSIDs

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18
Q

802.11a

A

provides up to 54 Mbps and operates in the 5-GHz band

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19
Q

802.11b

A

provides a transfer rate of up to 11 Mbps and works in the 2.4 GHz frequency range

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20
Q

802.11g

A

operates in the 2.4-GHz band and supports data rates of up to 54 Mbps

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21
Q

802.11n

A

aka Wi-Fi 4; supports throughputs of up to 100 Mbps and works in the 5-GHz band

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22
Q

IEEE 802.11ac

A

Wi-Fi 5; an extension of 802.11n which increases throughput to 1.3 Gbps and is backward compatible with a, b, g, and n

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23
Q

802.11ax standard

A

aims to address efficiency rather than faster speeds

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24
Q

Li-Fi

A

wireless networking tech which uses light rather than radio waves to transmit and receive data

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25
Q

802.16

A

MAN wireless standard; allows wireless traffic to cover large geographical areas where stations can be as far as 70 km apart, using 2.4-GHz and 5-GHz bands

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26
Q

MAN

A

metropolitan area network

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27
Q

802.15.4 standard

A

defines the physical layer and Media Access Control sublayer of wireless personal area networks

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28
Q

WPANs

A

wireless personal area networks

29
Q

ZigBee standard

A

for layers 3 (network) and 7 (application) built on top of 802.15.4 and commonly used in Internet of Things (IoT) and Industrial IoT systems

30
Q

Bluetooth standard

A

for WPANs; commonly used to replace the cables connecting peripherals to computers and mobile devices

31
Q

802.11e standard

A

provides Quality of Service and support of multimedia traffic in wireless transmissions

32
Q

QoS

A

Quality of Service

33
Q

802.11f standard

A

used when access points transfer active connections among themselves, enabling users to roam across APs

34
Q

802.11h standard

A

addresses interference issues in 5-GHz band regarding radar and satellite systems; using DFS and TPC techniques

35
Q

DFS

A

Dynamic Frequency Selection

36
Q

TPC

A

Transmit Power Control

37
Q

802.11j standard

A

allow common technologies like WLANs to be employed in countries (Japan) where local regulations conflict with portions of a broader standard like 802.11

38
Q

802.11

A

original WLAN which included WEP and is now obsolete

39
Q

WEP

A

Wired Equivalent Privacy

40
Q

802.11i

A

defines WPA2 and the common standard used in WLANs today

41
Q

WPA2

A

Wi-Fi Protected Access 2

42
Q

IEEE 802.11w standard

A

provides Management Frame Protection (MFP) which prevents certain attacks like replay and DoS attacks

43
Q

WPA3

A

developed by Wi-Fi alliance (not IEEE) and replacing WPA2 for both personal and enterprise use

44
Q

802.1X

A

access control protocol; implemented on both wired and wireless networks for user authentication and key distribution

45
Q

Mobile telephony

A

gone through different generations and multiple access technologies: 1G, 2G, 3G, 4G, 5G

46
Q

1G

A

FDMA

47
Q

2G

A

TDMA

48
Q

3G

A

CDMA

49
Q

4G

A

OFDM

50
Q

5G

A

OFDM

51
Q

Satellite communication links provide connectivity across very …. distances and in places …. but may introduce … challenges

A

across very long distances and in places that would otherwise not be reachable, but may introduce latency challenges

52
Q

Characteristics of IEEE 802.11a standard

A

OFDM spread-spectrum tech, works in 5-GHz frequency band, provides bandwidth up to 54 Mbps, covers smaller distance than 802.11b (operating range is smaller because it works at a higher frequency

53
Q

Characteristics of WPA2 in Enterprise mode

A

IEEE 802.1X or preshared keys for access control, EAP or preshared keys for authentication, AES in counter mode with CCMP for encryption

54
Q

EAP

A

Extensible Authentication Protocol

55
Q

AES

A

Advanced Encryption Standard algorithm

56
Q

CCMP

A

CBC-MAC Protocol

57
Q

Characteristics of Li-Fi networks

A

Low latency, support for high client densities, constrained coverage area, can work on the infrared spectrum

58
Q

Latency

A

delay in data transfer

59
Q

security of a ZigBee system

A

using a Trust Center to centrally authenticate devices and securely manage encryption keys which are 128 bits. Without a Trust Center, the Symmetric-Key Key Establishment (SKKE) protocol can be used to derive keys, but this approach is not as secure.

60
Q

bluesnarfing

A

attacker can read, modify, or delete calendar events, contacts, emails, texts

61
Q

bluejacking

A

Bluetooth attack; someone sending an unsolicited message to a device

62
Q

IEEE 802.1X standard covers …

A

access control protocol that can be implemented on both wired and wireless for user authentication and key distribution

63
Q

MFP covered in …

A

Management Frame Protection is covered in 802.11w

64
Q

WPA2 (Wi-Fi Protected Access 2) covered in …

A

802.11i standard

65
Q

Disadvantages of satellite networks compared to terrestrial ones

A

More expensive, higher latencies, not well suited for time-sensitive applications like voice and video conferencing

66
Q

Challenges of switching from WPA2 Personal mode to Enterprise mode

A

Embedded and IIoT devices do not support Enterprise mode and would have to be replaced, so the return on investment is insufficient

67
Q

If a WAP supports WPA2, it would do so in … or … mode

A

either Personal or Enterprise mode with no need for additional licensing

68
Q

WAP supports WPA2 as long as it can be connected to …

A

the needed backend services (e.g., a RADIUS server)