Deck 6: Wireless Lans I

Question 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 1

A

Question 2

Wi-Fi normally uses a(n)________.

A) omnidirectional antenna
B) dish antenna
C) both A and B
D) neither A nor B

Answer 2

A

Question 3

Wi-Fi is a term used by the ________.

A) IEEE
B) Wi-Fi Alliance
C) both A and B
D) neither A nor B

Answer 3

B

Question 4

The most serious problem with wireless transmission in WLANs is ________.

A) inverse square law attenuation
B) absorptive attenuation
C) shadow zones
D) multipath interference

Question 5

What propagation problem becomes worse when there is a large,and dense,object between sender and receiver?

A) multipath interference
B) shadow zones (dead zones)
C) inverse square law attenuation
D) none of the above

Question 6

If the signal strength from an omnidirectional radio source is 100 mW at 10 meters,how strong will it be at 30 meters,ignoring absorptive attenuation?

A) about 30 mW
B) about 11 mW
C) about 4 mW
D) about 0.1 mW

Question 7

Wi-Fi Standards come from the ________ Working Group.

A) 802.1
B) 802.3
C) 802.11
D) 802.1X

Question 8

If another wireless device is near,but in an unknown direction,it is better to use ________.

A) an omnidirectional antenna
B) a dish antenna
C) neither A nor B

Question 9

________ is a wireless network standard.

A) OSI
B) TCP/IP
C) both A and B
D) neither A nor B

Question 10

What propagation problem is especially bad in moist air?

A) absorptive attenuation
B) electromagnetic interference
C) multipath interference
D) inverse square law attenuation

Question 11

If a signal has a strength of 100 mW at 10 meters,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

Question 12

Wireless access points typically link wireless clients to ________.

A) wireless servers
B) servers on the wired network
C) both A and B

Question 13

Frequency is measured in terms of ________.

A) nanometers
B) hertz
C) microns
D) microseconds

Question 14

Compared to wired transmission,propagation problems in radio transmissions are ________.

A) worse
B) about as bad
C) better

Question 15

Simple installation rules are sufficient to reduce propagation problems to nonissues in ________.

A) 802.3
B) 802.11
C) both A and B
D) neither A nor B

Question 16

Most wireless systems operate in the ________ range.

A) hz
B) kHz
C) MHz
D) GHz

Question 17

Wireless radio transmission speed is usually measured in terms of ________.

A) wavelength
B) frequency
C) amplitude
D) dollars

Question 18

If a signal has a strength of 100 mW at 10 meters,how strong will it be at 100 meters?

A) about 10 mW
B) about 1 mW
C) about 0.1
D) none of the above

Question 19

We use the terms Wi-Fi and ________ interchangeably in this book.

A) 802.1
B) 802.3
C) 802.11
D) 802.1X

Question 20

In a Wi-Fi LAN,wireless hosts generally send frames directly to one another.

Question 21

WLANs normally use ________.

A) licensed bands
B) unlicensed bands
C) both A and B
D) neither A or B

Question 22

What is the bandwidth of a channel that extends from 55 MHz to 60 MHz?

A) 60 MHz
B) 55 MHz
C) 65 MHz
D) none of the above

Question 23

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

Question 24

Many 802.11 standards work in the 5 GHz_____.

A) licensed spectrum
B) unlicensed spectrum
C) licensed service band
D) unlicensed service band

Question 25

Multipath interference is mitigated through ________.

A) broadband transmission
B) MIMO
C) beamforming
D) spread spectrum transmission

Question 26

In Wi-Fi,2.4 GHz and 5 GHz refer to ________.

A) frequency spectrums
B) broadbands
C) channels
D) none of the above.

Question 27

An FM radio station is called Moldy Oldies 101.1.The 101.1 refers to its ________.

A) single frequency
B) channel
C) service band
D) none of the above

Question 28

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

Question 29

Wi-Fi standards use unlicensed bands for ________

A) greater speed
B) greater standardization
C) greater flexibility
D) greater privacy

Question 30

The downside of unlicensed bands is potential ________

A) speed loss
B) loss of flexibility
C) interference from others
D) less-developed standards

Question 31

The term "broadband" is commonly used for ________.

A) wide radio bandwidths
B) high-speed transmission in general
C) both A and B
D) neither A nor B

Question 32

To transmit very rapidly in radio,you need ________.

A) single-frequency transmission
B) single-mode transmission
C) wide bandwidth
D) narrow bandwidth

Question 33

If you want to transmit 7 times as fast in radio,you need to use ________.

A) channels that are about 7 times as wide
B) channels that are about 49 times as wide
C) spread spectrum transmission
D) none of the above

Question 34

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

Question 35

To transmit data very rapidly,you would want a ________ channel.

A) narrowband
B) broadband
C) single-frequency band
D) single-mode

Question 36

Wi-Fi operates in the 2.4GHz and 5GHz ________.

A) frequencies
B) spectrums
C) channels
D) service bands

Question 37

The frequency spectrum extends ________.

A) into the gigahertz range
B) into the visible light range
C) into the ultraviolet range
D) to infinity

Question 38

To handle multiple conversations in 802.11 transmission,you normally use multiple ________.

A) channels
B) frequencies
C) service bands
D) wires

Question 39

The set of frequencies used for police communication in a city are ________.

A) channels
B) frequencies
C) spectrums
D) none of the above

Question 40

Channels with wide bandwidths are called ________ channels.

A) multimode
B) full-duplex
C) broadband
D) parallel

Question 41

Access points take ________ from wireless devices and send them on to devices on the wired LAN.

A) packets
B) frames
C) both A and B
D) neither A nor B

Question 42

________ have SSIDs.

A) Wireless clients
B) Wireless access points
C) both A and B
D) neither A nor B

Question 43

802.11 operates in the ________ unlicensed service band.

A) 2.4 MHz
B) 60 MHz
C) both A and B
D) neither A nor B

Question 44

To use an access point,you need to know its ________.

A) SSID
B) BSSID
C) ESSID
D) Wi-Fi ID

Question 45

To connect to an access point,you must know its ________.

A) SSID
B) ESSID
C) IP address
D) Wi-Fi ID

Question 46

The 2.4 GHz band supports ________ possible non-overlapping 20 MHz channel(s).

A) 1
B) 3
C) 7
D) 11

Question 47

Companies prefer 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

Question 48

If you triple channel bandwidth,what happens to the number of channels in a service band?

A) It triples.
B) It increases by a factor of nine.
C) It is reduced a third.
D) It is reduced a ninth.

Question 49

Two access points that operate on the same channel will ________.

A) bond
B) coordinate their use of the channel
C) interfere
D) divide the available spectrum about equally

Question 50

Spread spectrum transmission's wider channels brings ________.

A) greater speed
B) greater reliability
C) greater security
D) none of the above

Question 51

In an extended service set,each access point ________.

A) must have the same SSID
B) must have a different SSID
C) must have a coordinated SSID
D) none of the above

Question 52

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

Question 53

Which of the following uses OFDM?

A) 802.11ac
B) 802.11n
C) both A and B
D) neither A nor B

Question 54

Access points in the same ESS communicate via ________.

A) wireless transmission
B) the distribution system
C) a master access point
D) routers

Question 55

If 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

Question 56

In general,the fewer the channels,________.

A) the greater the likelihood of interference between access points
B) the smaller the individual channels will be
C) both A and B
D) neither A nor B

Question 57

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

Question 58

In roaming,a wireless client moves from one ________ to another without losing its connection.

A) ESS
B) BSS
C) SSID
D) none of the above

Question 59

Spread spectrum transmission is used in WLANs for ________.

A) higher transmission speed
B) more reliable transmission
C) greater security
D) more efficient transmission

Question 60

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.

Question 61

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

Question 62

In CSMA/CA,CS means ________.

A) cancel sending
B) counter-source
C) carriage suspension
D) carrier sense

Question 63

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

Question 64

When a receiver transmits an ACK,________.

A) it must use CSMA/CA
B) it must use CSMA
C) in must use CA
D) it must transmit immediately

Question 65

When does it make sense to use RTS/CTS?

A) when all devices can hear each other
B) when not all of the devices can hear each other
C) when efficiency is crucial
D) always

Question 66

Which is one of the only two reliable protocols we have seen this term?

A) IP
B) CSMA/CA+ACK
C) UDP
D) 802.3

Question 67

MIMO ________.

A) increases throughput
B) lowers propagation distance
C) both A and B
D) neither A nor B

Question 68

Today,Wi-Fi sales are dominated by ________.

A) 802.11a
B) 802.11g
C) 802.11n
D) 802.11ac

Question 69

________ is among the most widely used 802.11 transmission standards used today.

A) 802.11g
B) 802.11ac
C) both A and B
D) neither A nor B

Question 70

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

Question 71

Media access control governs transmission by ________.

A) access points
B) wireless hosts
C) both A and B
D) neither A nor B

Question 72

CSMA/CA+ACK is ________.

A) unreliable
B) reliable
C) semireliable

Question 73

________ is a technique for preventing two wireless stations from interfering with each other by transmitting at the same time.

A) Creating extended service sets
B) Roaming
C) The distribution system
D) Media access control

Question 74

Within a BSS (and without MU-MIMO),the access point and a wireless host it serves can transmit at the same time.

Question 75

As your wireless client travels away from an access point,________.

A) errors begin to increase
B) your transmission speed decreases
C) both A and B
D) neither A nor B

Question 76

Which of the following is more efficient and faster?

A) CSMA/CA+ACK
B) RTS/CTS
C) Both are about equally efficient and fast.

Question 77

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

Question 78

The 802.11 standard has two mechanisms for media access control.Of the two,________ is mandatory.

A) MAC
B) CSMA/CA+ACK
C) RTS/CTS
D) CSMA/CD

Question 79

MIMO ________.

A) increases transmission speed
B) increases transmission distance
C) both A and B
D) neither A nor B

Question 80

Individual throughput for users of an access point ________.

A) depends on how many users are sharing the access point
B) depends on your distance from the access point
C) both A and B
D) neither A nor B