Chapter 6 Wireless LANS I (other)

77) Which of the following can operate in the 5 GHz band? A) 802.11ac B) 802.11g C) Both A and B D) Neither A nor B

A) 802.11ac

79) In the 60 GHz service band, ________. A) channel bandwidth can be very wide B) signals travel farther C) Both A and B D) Neither A nor B

A) channel bandwidth can be very wide

MIMO ________. A) increases throughput B) lowers propagation distance C) Both A and B D) Neither A nor B

A) increases throughput

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

A) individual throughput

94) 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

A) only wireless devices

50) There is an access point that serves eight wireless hosts. On how many channels will these devices transmit during the course of an hour or two? A) 1. B) 2 (one in each direction). C) 7. D) 8. E) 9.

Answer: A A) 1.

33) Which unlicensed band is defined the same way in most countries around the world? A) 2.4 GHz. B) 5 GHz. C) Both A and B D) None of the above.

Answer: A A) 2.4 GHz.

34) Which unlicensed band provides greater propagation distance for a given level of power? A) 2.4 GHz. B) 5 GHz. C) Both A and B allow about the same propagation distance.

Answer: A A) 2.4 GHz.

12) What propagation problem becomes worse as frequency increases? A) Absorptive attenuation. B) Electromagnetic interference. C) Both A and B D) Neither A nor B

Answer: A A) Absorptive attenuation.

61) (From the box, "Controlling 802.11 Transmission") Which of the following is more efficient? A) CSMA/CA+ACK. B) RTS/CTS. C) Both are about equally efficient.

Answer: A A) CSMA/CA+ACK.

2) Wireless network standards come from ________. A) OSI B) TCP/IP C) Both A and B D) Neither A nor B

Answer: A A) OSI

37) What aspect of 802.11 standards affects interference between nearby access points? A) The number of possible nonoverlapping channels. B) The standard's minimum spacing parameter. C) RTS/CTS. D) All of the above.

Answer: A A) The number of possible nonoverlapping channels.

36) 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 use CSMA/CA+ACK. D) They will be bonded for joint operation automatically if they use RTS/CTS.

Answer: A A) They will interfere with each other.

49) In 802.11 WLANs, the terms handoff and roaming mean the same thing. A) True. B) False.

Answer: A A) True.

52) Individual throughput falls as the number of wireless hosts using an access point increases. A) True. B) False.

Answer: A A) True.

55) (From the box, "Controlling 802.11 Transmission") When a wireless NIC receives a frame correctly, it immediately sends back a reply without listening for traffic. A) True. B) False.

Answer: A A) True.

56) (From the box, "Controlling 802.11 Transmission") CSMA/CA+ACK is reliable. A) True. B) False.

Answer: A A) True.

70) As a wireless host moves farther from a wireless access point, it is likely to transition to a slower modulation method. A) True. B) False.

Answer: A A) True.

9) The signal strength at 20 meters is 90 mW the signal strength at 60 meters would be 10 mW. A) True. B) False.

Answer: A A) True.

27) If a radio transmission is easily blocked by obstacles, then you need to maintain ________. A) a clear line of sight B) spread spectrum transmission integrity C) broadband transmission D) deep transmission E) shadow zone transmission

Answer: A A) a clear line of sight

5) Cellular telephony uses ________. A) an omnidirectional antenna B) a dish antenna C) Both A and B D) Neither A nor B

Answer: A A) an omnidirectional antenna

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

Answer: A A) channels

78) Smart antennas can ________. A) direct signal strength at individual wireless hosts B) transmit multiple spatial data streams in the same channel C) Both A and B D) Neither A nor B

Answer: A A) direct signal strength at individual wireless hosts

39) 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 A) it is required by regulators

29) Interference is minimized in ________. A) licensed bands B) unlicensed bands

Answer: A A) licensed bands

77) 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 A) only wireless devices

59) (From the box, "Controlling 802.11 Transmission") CSMA/CA+ACK usually is ________. A) required B) optional

Answer: A A) required

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 A) the data link layer The data link layer and the physical layer.

30) 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 A) you can use radios wherever you please

47) 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) 3. D) 4. E) There will be one frame for each switch along the way.

Answer: B B) 2.

35) The 2.4 GHz band supports ________ nonoverlapping channels. A) 1 B) 3 C) 7 D) 11 E) more than 11

Answer: B B) 3

67) 802.11g has a rated speed of ________. A) 11 Mbps B) 54 Gbps C) 300 Mbps D) 1 Gbps

Answer: B B) 54 Gbps

17) The terms channel and service band mean roughly the same thing. A) True. B) False.

Answer: B B) False.

41) Spread spectrum transmission is used in commercial WLANs for security reasons. A) True. B) False.

Answer: B B) False.

45) Access points take frames from wireless devices and send these frames on to devices on the wired LAN. They also do the converse. A) True. B) False.

Answer: B B) False.

51) An access point and a host it serves can transmit to each other simultaneously. A) True. B) False.

Answer: B B) False.

62) The most widely used 802.11 LAN standard today is 802.11n. A) True. B) False.

Answer: B B) False.

64) The most rapidly growing 802.11 LAN standard today is 802.11g. A) True. B) False.

Answer: B B) False.

7) Radio has more reliable transmission than UTP. A) True. B) False.

Answer: B B) False.

66) There is less interference in the 2.4 GHz band than in the 5 GHz band. A) True. B) False.

Answer: B B) False. More interference

60) (From the box, "Controlling 802.11 Transmission") Which of the following is usually optional in access point operation? A) CSMA/CA+ACK. B) RTS/CTS. C) Both A and B D) Neither A nor B

Answer: B B) RTS/CTS.

54) (From the box, "Controlling 802.11 Transmission") When a wireless NIC wishes to transmit, it listens for traffic. If there is traffic, it waits. If there is no traffic, it may transmit. A) True. B) Sometimes true. C) False.

Answer: B B) Sometimes true.

6) The other wireless device is far away in a known direction. You should use ________. A) an omnidirectional antenna B) a dish antenna C) Both A and B D) Neither A nor B

Answer: B B) a dish antenna

69) An 802.11g access point has an actual speed of 30 MHz. This is ________. A) the rated speed B) aggregate throughput C) channel bandwidth

Answer: B B) aggregate throughput

23) To transmit data very rapidly, you would want a ________ channel. A) narrowband B) broadband C) single-frequency band D) Any of the above.

Answer: B B) broadband

3) Wireless radio transmission usually is expressed in terms of ________. A) wavelength B) frequency C) Both A and B D) Neither A nor B

Answer: B B) frequency

4) Frequency is measured in terms of ________. A) nanometers B) hertz C) Both A and B D) Neither A nor B

Answer: B B) hertz

57) (From the box, "Controlling 802.11 Transmission") CSMA/CA+ACK is ________. A) efficient B) inefficient

Answer: B B) inefficient

24) In the Shannon Equation, C is the ________. A) actual speed of transmission in a channel B) maximum possible speed of transmission in a channel C) minimum possible speed of transmission in a channel D) channel bandwidth E) signal-to-noise ratio

Answer: B B) maximum possible speed of transmission in a channel

40) Spread spectrum transmission is used in WLANs for ________. A) higher transmission speed B) more reliable transmission C) greater security D) All of the above.

Answer: B B) more reliable transmission

46) Access points take ________ from wireless devices and send them on to devices on the wired LAN. They also do the converse. A) frames B) packets

Answer: B B) packets

8) Attenuation with distance is faster with ________. A) UTP transmission B) radio transmission C) Both A and B D) Neither A nor B

Answer: B B) radio transmission

19) Signals usually ________. A) travel at a single frequency B) spread over a range of frequencies

Answer: B B) spread over a range of frequencies

28) WLANs normally use ________. A) licensed bands B) unlicensed bands

Answer: B B) unlicensed bands

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

Answer: C C) 20 MHz

73) 802.11n may offer a rated speed of about ________. A) 11 Mbps B) 54 Mbps C) 300 Mbps D) 3 Gbps

Answer: C C) 300 Mbps

14) Wireless LAN standards are created by the ________ Working Group. A) 802.1 B) 802.3 C) 802.11 D) 802.3W

Answer: C C) 802.11

75) Which of the following can offer speeds of about a gigabit per second? A) 802.11g. B) 802.11n. C) 802.11ac. D) None of the above.

Answer: C C) 802.11ac.

13) What propagation problem becomes worse as frequency increases? A) Absorptive attenuation. B) Shadow zones. C) Both A and B D) Neither A nor B

Answer: C C) Both A and B

31) 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) None of the above.

Answer: C C) Both A and B

43) Which of the following uses OFDM? A) 802.11g. B) 802.11n. C) Both A and B D) Neither A nor B

Answer: C C) Both A and B

48) When a host moves from one wireless access point to another in a WLAN, this is ________. A) a handoff B) roaming C) Both A and B D) Neither A nor B

Answer: C C) Both A and B

53) (From the box, "Controlling 802.11 Transmission") Media access control governs transmission by ________. A) access points B) wireless NICs C) Both A and B D) Neither A nor B

Answer: C C) Both A and B

65) 802.11n is designed to operate in the ________ unlicensed band. A) 2.4 GHz B) 5 GHz C) Both A and B D) Neither A nor B

Answer: C C) Both A and B

68) 802.11n is faster than 802.11g because 802.11n ________ A) is designed to use wider channels B) can send multiple signals (spatial transmission speeds) in a single channel C) Both A and B D) Neither A nor B

Answer: C C) Both A and B

71) Which of the following is true? A) An 802.11n host can work with an 802.11g access point. B) An 802.11g host can work with an 802.11n access point. C) Both A and B D) Neither A nor B

Answer: C C) Both A and B

72) 802.11n will be superior to current 802.11 standards by ________. A) offering wider channels B) sending multiple spatial data streams in a single channel between wireless access points and wireless NICs C) Both A and B D) Neither A nor B

Answer: C C) Both A and B

74) MIMO increases ________. A) throughput B) propagation distance C) Both A and B D) Neither A nor B

Answer: C C) Both A and B

76) 802.11ad will ________. A) operate in the 60 GHz radio band B) have short propagation distance C) Both A and B D) Neither A nor B

Answer: C C) Both A and B

44) Which form of spread spectrum transmission divides the channel into many smaller channels called subcarriers? A) DSSS. B) FHSS. C) OFDM. D) All of the above. E) None of the above.

Answer: C C) OFDM.

25) In the Shannon Equation, if you quadruple the bandwidth in a channel while the signal-to-noise ratio remains the same, you can transmit ________. A) Log2(1+4) times as fast B) Log2(1+1/4) times as fast C) about 4 times as fast D) about 1/4 as fast E) at the same speed, but more reliably

Answer: C C) about 4 times as fast

42) A channel has more bandwidth than is necessary given data transmission speeds requirements in ________ transmission. A) normal radio B) reliable commercial C) spread spectrum transmission D) licensed E) None of the above.

Answer: C C) spread spectrum transmission

63) The most widely used 802.11 standard today is ________. A) 802.11a B) 802.11b C) 802.11e D) 802.11g E) 802.11n

Answer: D D) 802.11g

38) 802.11a supports ________ nonoverlapping channels. A) 1 B) 3 C) 7 D) More than 10

Answer: D D) More than 10

11) 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 D) Neither A nor B

20) 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 D) None of the above.

58) (From the box, "Controlling 802.11 Transmission") 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 D) RTS/CTS

16) The total range of possible 802.11 WLAN frequencies in the 2.4 GHz band constitutes ________. A) a frequency spectrum B) a broadband C) a channel D) a service band E) All of the above.

Answer: D D) a service band

22) Channels with wide bandwidths are called ________ channels. A) single-mode B) multimode C) full-duplex D) broadband E) modulated

Answer: D D) broadband

26) The frequency range from 500 megahertz to 10 gigahertz is called the ________. A) frequency spectrum B) commercial mobile service band C) UWB region D) golden zone E) unlicensed band

Answer: D D) golden zone

10) 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 D) multipath interference

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

Answer: D D) wide bandwidth

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

Answer: E E) to infinity

Which of the following brings gigabit speeds to clients? A) 802.11n B) 802.11ac C) 802.11g D) None of the above

B) 802.11ac

91) If an 802.11n access point and an 802.11g client communicate, they communicate using ________. A) 802.11n B) 802.11g C) Either A or B D) Neither A nor B

B) 802.11g

Traditional MIMO can ________ A) send signals to two different clients at the same time B) send multiple signals in the same channel C) Both A and B D) Neither A nor B

B) send multiple signals in the same channel

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

C) 6

For wireless backup, which of the following is adequate? A) 802.11g B) 802.11n C) 802.11ac D) All of the above

C) 802.11ac

71) For which standard is 300 Mbps a typical rated speed? A) 802.11ad. B) 802.11ac. C) 802.11n. D) 802.11g.

C) 802.11n.

83) Beamforming can ________. A) direct signal strength at individual wireless hosts B) transmit multiple spatial data streams in the same channel C) Both A and B D) Neither A nor B

C) Both A and B

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

C) Both A and B

87) In 802.11 networks, the speed I receive on my portable devices is a(n) ________. A) individual throughput B) rated speed C) aggregate throughput D) None of the above

C) aggregate throughput

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

C) transmits multiple signals in the same channel

Using unused transmission channels in a service band is called using ________. A) dark spectrum B) opportunistic agility C) white space D) a smart antenna

C) white space

70) Which of the following is a draft standard, according to the book? A) 802.11n. B) 802.11g. C) Both A and B D) Neither A nor B

D) Neither A nor B

72) For which of the following is 100 meters a typical service distance? A) 802.11n. B) 802.11g. C) Both A and B D) Neither A nor B

D) Neither A nor B

76) Wider channel bandwidth ________. A) allows more channels to be used in a service band B) decreases transmission speed C) Both A and B D) Neither A nor B

D) Neither A nor B

93) Two wireless devices communicate via Wi-Fi Direct using ________. A) an access point that lets them talk directly B) an Ethernet network to connect their access points C) Either A or B D) Neither A nor B

D) Neither A nor B

Which of the following is a full, according to the book? A) 802.11ac. B) 802.11ad. C) Both A and B D) Neither A nor B

D) Neither A nor B

95) The 802.11 standard for mesh networking is ________. A) 802.11r B) 802.11m C) 802.11ac D) None of the above

D) None of the above

Two WLAN products that conform to the same standard will have almost equal performance. (True or False)

False Will not have equal performance.

If a wireless client only has two MIMO antennas, an access point with three MIMO antennas will produce better performance than an access point with two MIMO antennas. (True or False)

True

The presence of a client that is distant from the access point reduces the individual throughput of other clients served by that access point. (True or False)

True

81) MIMO allows you to transmit two signals in the same channel. (True or False)

True.

86) Another name for beamforming is having a smart antenna. (True or False)

True.

As a station moves away from an access point, the access point transmits more slowly to it.(True or False)

True.