Deck 6: Wireless Lans I

Question 1

Attenuation increases with distance faster with ________.

A)UTP transmission
B)radio transmission
C)both A and B about equally

Answer 1

B

Question 2

Signals usually ________.

A)travel at a single frequency
B)spread over a range of frequencies

Answer 2

B

Question 3

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 3

D

Question 4

Radio has more reliable transmission than UTP.

Question 5

Wireless access points typically link wireless clients to ________.

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

Question 6

To handle multiple conversations in radio transmission,you use multiple ________.

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

Question 7

Wireless network standards operate at ________.

A)the data link layer
B)the internet layer
C)both A and B
D)neither A nor B

Question 8

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

Question 9

Wireless radio transmission usually is expressed in terms of ________.

A)wavelength
B)frequency
C)both A and B
D)neither A nor B

Question 10

Wireless network standards come from ________.

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

Question 11

The frequency spectrum extends ________.

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

Question 12

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 13

If the signal strength at 20 meters is 90 mW,the signal strength at 60 meters would be 10 mW.

Question 14

Cellular telephones use ________.

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

Question 15

Wireless LAN standards are created by the ________ Working Group.

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

Question 16

What propagation problem becomes worse as frequency increases?

A)absorptive attenuation
B)shadow zones
C)both A and B
D)neither A nor B

Question 17

The other wireless device is far away in a known direction.You should use ________.

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

Question 18

Frequency is measured in terms of ________.

A)nanometers
B)hertz
C)both A and B
D)neither A nor B

Question 19

The terms channel and service band mean roughly the same thing.

Question 20

What propagation problem becomes worse as frequency increases?

A)absorptive attenuation
B)electromagnetic interference
C)both A and B
D)neither A nor B

Question 21

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)neither A nor B

Question 22

In 802.11g,channel bandwidth usually is ________.

A)20 GHz
B)40 GHz
C)20 MHz
D)40 MHz

Question 23

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

Question 24

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)at the same speed, but more reliably

Question 25

Channels with wide bandwidths are called ________ channels.

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

Question 26

Networks that are fast are often called broadband whether or not they use radio channels.

Question 27

To transmit very rapidly in RADIO,you need ________.

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

Question 28

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.

Question 29

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 30

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

A)narrowband
B)broadband
C)single-frequency band
D)any of the above

Question 31

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

Question 32

The 2.4 GHz band supports ________ nonoverlapping 20 MHz channel(s).

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

Question 33

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 34

Interference is minimized in ________.

A)licensed bands
B)unlicensed bands

Question 35

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

Question 36

Spread spectrum transmission is used in WLANs for ________.

A)higher transmission speed
B)more reliable transmission
C)greater security
D)all of the above

Question 37

The frequency range from 500 megahertz to 10 gigahertz is called the ________.

A)frequency spectrum
B)commercial mobile service band
C)unlicensed band
D)golden zone

Question 38

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

Question 39

The 5 GHz band supports about ________ nonoverlapping 20 MHz channel(s).

A)1
B)3
C)6
D)12

Question 40

WLANs normally use ________.

A)licensed bands
B)unlicensed bands

Question 41

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

A)BSSID
B)DSS
C)ESSID
D)none of the above

Question 42

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

Question 43

An access point and a host it serves can transmit to each other simultaneously.

Question 44

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)7
D)8

Question 45

In 802.11 WLANs,the terms handoff and roaming mean the same thing.

Question 46

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.

Question 47

Access points take frames from wireless devices and send these frames on to devices on the wired LAN.

Question 48

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

Question 49

The standard for roaming among access points is ________.

A)802.11r
B)802.11s
C)802.11W
D)none of the above

Question 50

Which of the following uses OFDM?

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

Question 51

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

Question 52

The identifier of the access point in a basic service set us the ________.

A)SSID
B)BSSID
C)ESSID

Question 53

________ 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

Question 54

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 55

When a WLAN is in use,the distribution system is the ________.

A)collection of access points
B)Ethernet network
C)radio transmitter in an access point
D)radio transmitter in the access point controller

Question 56

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

Question 57

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

Question 58

Spread spectrum transmission is used in commercial WLANs for security reasons.

Question 59

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 60

Media access control governs transmission by ________.

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

Question 61

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

Question 62

In the 60 GHz service band,________.

A)signals travel farther
B)channel bandwidth can be very wide
C)both A and B
D)neither A nor B

Question 63

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 64

MIMO ________.

A)bonds 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 65

For wireless backup,which of the following is adequate?

A)802.11ac
B)802.11g
C)802.11n
D)all of the above

Question 66

Which of the following is a draft standard,according to the book?

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

Question 67

When a wireless NIC using CSMA/CD receives a frame correctly,it immediately sends back a reply without listening for traffic.

Question 68

Which of the following is a full standard,according to the book?

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

Question 69

Which of the following has longer range?

A)802.11g
B)802.11n
C)Both have about the same range.

Question 70

CSMA/CA+ACK is reliable.

Question 71

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

Question 72

Which of the following can bring gigabit speeds to clients?

A)802.11ac
B)802.11g
C)802.11n
D)none of the above

Question 73

For which standard is 300 Mbps a typical rated speed?

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

Question 74

Which of the following is more efficient?

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

Question 75

CSMA/CA+ACK usually is ________.

A)required
B)optional

Question 76

Wider channel bandwidth ________.

A)decreases transmission speed
B)allows more channels to be used in a service band
C)both A and B
D)neither A nor B

Question 77

Which of the following uses OFDM?

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

Question 78

Which of the following can operate in the 5 GHz band?

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

Question 79

CSMA/CA+ACK is ________.

Question 80

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