Chapter 6 Wireless LANs I Flashcards Preview

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Flashcards in Chapter 6 Wireless LANs I Deck (69):
1

1) Wireless network standards operate at ________.
A) the data link layer
B) the Internet layer
C) both A and B
D) neither A nor B

Answer: A

2

2) Wireless network standards are ________ standards.
A) OSI
B) TCP/IP
C) both A and B

Answer: A

3

3) Wi-Fi Standards come from the ________ Working Group.
A) 802.1
B) 802.3
C) 802.11
D) 802.1X

Answer: C

4

4) We use the terms Wi-Fi and ________ interchangeably in this book.
A) 802.1
B) 802.3
C) 802.11
D) 802.1X

Answer: C

5

5) Wireless access points typically link wireless clients to ________.
A) wireless servers
B) servers on the wired network
C) both A and B

Answer: B

6

6) Compared to wired transmission, propagation problems in radio transmission are ________.
A) worse
B) about as bad
C) better

Answer: A

7

7) Wireless radio transmission speed is usually measured in terms of ________.
A) wavelength
B) frequency
C) amplitude
D) wetness

Answer: B

8

8) Frequency is measured in terms of ________.
A) nanometers
B) hertz
C) microns
D) microseconds

Answer: B

9

9) Radio transmission is measured in terms of ________.
A) bytes per second
B) wavelength
C) frequency
D) bits per second

Answer: C

10

10) The other wireless device is far away in a known direction. It would be better to use ________.
A) an omnidirectional antenna
B) a dish antenna
C) neither A nor B

Answer: B

11

11) A cellular telephone uses a(n) ________.
A) omnidirectional antenna
B) dish antenna
C) both A and B
D) neither A nor B

Answer: A

12

12) At 10 meters, a signal has a strength of 100 mW. About how strong will it be at 40 meters?
A) about 0.5 mW
B) about 5 mW
C) about 25 mW
D) about 6 mW

Answer: D

13

13) What propagation problem is especially bad in moist air?
A) absorptive attenuation
B) electromagnetic interference
C) multipath interference
D) inverse square law attenuation

Answer: A

14

14) What propagation problem becomes worse as there is a large and dense object between sender and receiver?
A) multipath interference
B) shadow zones or dead zones
C) both A and B
D) neither A nor B

Answer: B

15

15) The most serious problem with wireless transmission in WLANs is ________.
A) inverse square law attenuation
B) absorptive attenuation
C) shadow zones
D) multipath interference

Answer: D

16

16) What propagation problem becomes worse as frequency increases?
A) inverse square law attenuation
B) electromagnetic interference
C) both A and B
D) neither A nor B

Answer: D

17

17) The frequency spectrum extends ________.
A) into the gigahertz range
B) into the visible light range
C) into the ultraviolet range
D) to infinity

Answer: D

18

18) 2.4 GHz and 5 GHz are ________.
A) frequency spectrums
B) broadbands
C) channels
D) service bands

Answer: D

19

19) To handle multiple conversations in radio transmission, you normally use multiple ________.
A) channels
B) frequencies
C) service bands
D) wires

Answer: A

20

20) Signals in a transmission usually ________.
A) travel at a single frequency
B) spread over a range of frequencies
C) spread over the entire frequency distribution
D) spread over the entire service band

Answer: B

21

21) A channel extends from 55 MHz to 60 MHz. Its bandwidth is ________.
A) 60 MHz
B) 55 MHz
C) 65 MHz
D) none of the above

Answer: D

22

22) To transmit very rapidly in RADIO, you need ________.
A) single-frequency transmission
B) single-mode transmission
C) wide bandwidth
D) narrow bandwidth

Answer: C

23

23) Channels with wide bandwidths are called ________ channels.
A) multimode
B) full-duplex
C) broadband
D) parallel

Answer: C

24

24) To transmit data very rapidly, you would want a ________ channel.
A) narrowband
B) broadband
C) single-frequency band
D) none of the above

Answer: B

25

25) 802.11 standards are being developed to work in the ________ unlicensed band.
A) 2.4 GHz
B) 5 GHz
C) both A and B
D) neither A nor B

Answer: C

26

26) The 2.4 GHz band supports ________ possible non-overlapping 20 MHz channel(s).
A) 1
B) 3
C) 7
D) 11

Answer: B

27

27) Companies are moving to the 5 GHz band because there is ________ than in the 2.5 GHz band.
A) more bandwidth
B) less absorptive attenuation
C) both A and B
D) neither A nor B

Answer: A

28

28) The 5 GHz band usually supports about ________ non-overlapping 20 MHz channel(s).
A) 1
B) 3
C) 7
D) 12

Answer: D

29

29) Spread spectrum transmission is used in WLANs because ________.
A) it is required by regulators
B) it offers strong security
C) both A and B
D) neither A nor B

Answer: A

30

30) Spread spectrum transmission is used in WLANs for ________.
A) higher transmission speed
B) more reliable transmission
C) greater security
D) more efficient transmission

Answer: B

31

31) WLANs normally use ________.
A) licensed bands
B) unlicensed bands
C) both A and B
D) neither A or B

Answer: B

32

32) In unlicensed bands, ________.
A) you can use radios wherever you please
B) you can prevent nearby businesses from setting up access points in the same channel
C) both A and B
D) neither A nor B

Answer: A

33

33) A channel has more bandwidth than is necessary given data transmission speeds requirements in ________ transmission.
A) normal radio
B) reliable commercial
C) spread spectrum
D) licensed

Answer: C

34

34) Which of the following uses OFDM?
A) 802.11ac
B) 802.11n
C) both A and B
D) neither A nor B

Answer: C

35

35) Access points take ________ from wireless devices and send them on to devices on the wired LAN. They also do the converse.
A) packets
B) frames
C) both A and B
D) neither A nor B

Answer: A

36

36) A wireless host sends a packet to a server on the company's wired Ethernet LAN via an access point. How many frames will be involved in this one-way transmission?
A) 1
B) 2
C) 4
D) There will be one frame for each switch along the way.

Answer: B

37

37) A single access point and the set of hosts it serves is called a(n) ________.
A) BSS
B) BSSID
C) ESS
D) none of the above

Answer: A

38

38) ________ have SSIDs.
A) Wireless clients
B) Wireless access points
C) both A and B
D) neither A nor B

Answer: B

39

39) To use an access point, you need to know its ________.
A) SSID
B) BSSID
C) ESSID
D) Wi-Fi ID

Answer: A

40

40) To connect to an access point, you must know its ________.
A) SSID
B) EUI-48 address
C) IP address
D) Wi-Fi ID

Answer: A

41

41) An extended service set (ESS) is a group of BSSs that ________.
A) are connected to the same distribution system
B) have the same SSID
C) both A and B
D) neither A nor B

Answer: C

42

42) In an extended service set, each access point ________.
A) must have the same SSID
B) must have different SSIDs
C) must have coordinated SSIDs
D) none of the above

Answer: A

43

43) Access points in the same ESS communicate via ________.
A) wireless transmission
B) the distribution system
C) a master access point
D) routers

Answer: B

44

44) The standard for roaming among access points is ________.
A) 802.11r
B) 802.11s
C) 802.11W
D) the wireless handoff protocol

Answer: A

45

45) What happens if two nearby access points use the same channel?
A) They will interfere with each other.
B) They will be bonded for joint operation automatically.
C) They will be bonded for joint operation automatically if they are on the same ESS.
D) They will be bonded for joint operation automatically if they have the same SSID.

Answer: A

46

46) There is an access point that serves eight wireless hosts. On how many channels will these devices transmit and receive during the course of an hour or two?
A) 1
B) 2
C) 8
D) 9

Answer: A

47

47) ________ is a technique for preventing two wireless stations from transmitting at the same time and therefore interfering with each other.
A) Creating extended service sets
B) Roaming
C) The distribution system
D) Media access control

Answer: D

48

48) Media access control governs transmission by ________.
A) access points
B) wireless hosts
C) both A and B
D) neither A nor B

Answer: C

49

49) In CSMA/CD+ACK, when a wireless NIC wishes to transmit, it listens for traffic. If there is traffic, it waits. When the traffic stops, it may transmit immediately.
A) always true
B) sometimes true
C) always false

Answer: C

50

50) CSMA/CD+ACK is ________.
A) unreliable
B) reliable
C) semireliable

Answer: B

51

51) In ________, when a wireless host wishes to send, it first sends a message to the wireless access point asking for permission to send. When the access point sends back a response, the host sending the original message may transmit. All other hosts must wait.
A) CSMA/CA+ACK
B) CSMA/CA
C) CSMA/CD
D) RTS/CTS

Answer: D

52

52) The 802.11 standard has two mechanisms for media access control. One of two mechanisms is mandatory; it is ________.
A) MAC
B) CSMA/CA+ACK
C) RTS/CTS
D) CSMA/CD

Answer: B

53

53) CSMA/CA+ACK usually is ________.
A) mandatory
B) optional
C) not important
D) efficient

Answer: A

54

54) Which of the following is more efficient and faster?
A) CSMA/CA+ACK
B) RTS/CTS
C) Both are about equally efficient and fast.

Answer: A

55

55) Which of the following is the newest Wi-Fi standard?
A) 802.11ac
B) 802.11g
C) 802.11n
D) 802.11b

Answer: A

56

56) Today, Wi-Fi sales are dominated by ________.
A) 802.11a
B) 802.11g
C) 802.11n
D) 802.11ac

Answer: D

57

57) Wider channel bandwidth ________.
A) increases transmission speed
B) allows more channels to be used in a service band
C) both A and B
D) neither A nor B

Answer: A

58

58) Which of the following only operates in the 5 GHz band?
A) 802.11b
B) 802.11ac
C) 802.11g
D) 802.11n

Answer: B

59

59) In 802.11g, channel bandwidth usually is ________.
A) 20 GHz
B) 40 GHz
C) 20 MHz
D) 40 MHz

Answer: C

60

60) In the 5 GHz band, how many channels can you have with 802.11ac with 80 GHz channels?
A) 1
B) 6
C) 12
D) 24

Answer: B

61

61) MIMO ________.
A) bonds two or more channels for higher speed
B) is used in all forms of 802.11
C) uses a single spatial stream but multiple signals
D) transmits multiple signals in the same channel

Answer: D

62

62) MIMO ________.
A) increases throughput
B) lowers propagation distance
C) both A and B
D) neither A nor B

Answer: A

63

63) Beamforming can allow an access point to ________.
A) direct power to individual clients
B) send signals to two different clients at the same time
C) both A and B
D) neither A nor B

Answer: C

64

64) An access point can transmit to more than one wireless client at a time with ________.
A) bonding
B) MIMO
C) Multiuser MIMO
D) CSMC/CA+ACK

Answer: C

65

65) If more users move to an access point, this decreases ________.
A) individual throughput
B) aggregate throughput
C) both A and B
D) neither A nor B

Answer: A

66

66) If an 802.11n client tries to use an 802.11ac access point, ________.
A) they will not be able to communicate
B) they will communicate using 802.11n
C) they will communicate using 802.11ac
D) either B or C

Answer: B

67

67) (T/F) If two products both comply with 802.11 ac, they should have close to the same performance.

Answer: FALSE

68

68) Mesh networking in 802.11 is likely to use ________.
A) only wireless devices
B) wireless devices and the site's wired LAN
C) both A and B

Answer: A

69

69) The 802.11 standard for mesh networking is ________.
A) 802.11m
B) 802.11r
C) 802.11ac
D) 802.11s

Answer: D