CH 6 350
To transmit data very rapidly, you would want a ________ channel. A) narrowband B) broadband C) single-frequency band D) single-mode
B
WLANs normally use ________. A) licensed bands B) unlicensed bands C) both A and B D) neither A or B
B
What is the main promise of 802.11ax over 802.11ac? A) higher speed B) the ability to serve more users C) MIMO D) Mu-MIMO
B
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
B
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
B
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
A
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
A
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
A
Compared to wired transmission, propagation problems in radio transmissions are ________. A) worse B) about as bad C) better
A
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
A
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
A
Today, Wi-Fi sales are dominated by ________. A) 802.11a B) 802.11g C) 802.11n D) 802.11ac
D
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
A
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
A
If two products both comply with 802.11 ac, their performance will always be similar.
FALSE
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
A
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
A
MIMO ________. A) increases throughput B) lowers propagation distance C) both A and B D) neither A nor B
A
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
A
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
A
The 60 GHz unlicensed service band offers ________ compared to lower-frequency service bands. A) more speed per channel B) greater propagation distance C) greater ability to penetrate walls D) all of the above
A
To connect to an access point, you must know its ________. A) SSID B) ESSID C) IP address D) Wi-Fi ID
A
To handle multiple conversations in 802.11 transmission, you normally use multiple ________. A) channels B) frequencies C) service bands D) wires
A
To use an access point, you need to know its ________. A) SSID B) BSSID C) ESSID D) Wi-Fi ID
A
What propagation problem is especially bad in moist air? A) absorptive attenuation B) electromagnetic interference C) multipath interference D) inverse square law attenuation
A
Which of the following is more efficient and faster? A) CSMA/CA+ACK B) RTS/CTS C) Both are about equally efficient and fast.
A
Wi-Fi normally uses a(n) ________. A) omnidirectional antenna B) dish antenna C) both A and B D) neither A nor B
A
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
A
Wireless network standards operate at ________. A) the data link layer B) the Internet layer C) both A and B D) neither A nor B
A
________ is a wireless network standard. A) OSI B) TCP/IP C) both A and B D) neither A nor B
A
) Wireless access points typically link wireless clients to ________. A) wireless servers B) servers on the wired network C) both A and B
B
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.
B
Access points in the same ESS communicate via ________. A) wireless transmission B) the distribution system C) a master access point D) routers
B
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
B
CSMA/CA+ACK is ________. A) unreliable B) reliable C) semireliable
B
Frequency is measured in terms of ________. A) nanometers B) hertz C) microns D) microseconds
B
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
B
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
B
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
B
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
B
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
B
Spread spectrum transmission is used in WLANs for ________. A) higher transmission speed B) more reliable transmission C) greater security D) more efficient transmission
B
Spread spectrum transmission's wider channels brings ________. A) greater speed B) greater reliability C) greater security D) none of the above
B
The 2.4 GHz band supports ________ possible non-overlapping 20 MHz channel(s). A) 1 B) 3 C) 7 D) 11
B
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
B
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
B
Which of the following works in the 60 GHz unlicensed service band? A) 802.11ac B) 802.11ad C) 802.11ax D) all of the above
B
Wi-Fi is a term used by the ________. A) IEEE B) Wi-Fi Alliance C) both A and B D) neither A nor B
B
Wireless radio transmission speed is usually measured in terms of ________. A) wavelength B) frequency C) amplitude D) dollars
B
________ have SSIDs. A) Wireless clients B) Wireless access points C) both A and B D) neither A nor B
B
________ 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
B
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
C
An 802.11ac Wi-Fi compatibility testing profile contains ________ of the features of the 802.11ac. A) all B) nearly all C) some D) none
C
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
C
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
C
Beamforming can allow an access point to ________. A) focus power on individual clients B) send signals to two different clients at the same time C) both A and B D) neither A nor B
C
Because of ________, an 802.11AX access point can communicate with an 802.11AY client. A) MIMO B) MU-MIMO C) backward compatibility D) They CANNOT communicate
C
Channels with wide bandwidths are called ________ channels. A) multimode B) full-duplex C) broadband D) parallel
C
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
C
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.
C
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
C
MIMO ________. A) increases transmission speed B) increases transmission distance C) both A and B D) neither A nor B
C
Media access control governs transmission by ________. A) access points B) wireless hosts C) both A and B D) neither A nor B
C
The downside of unlicensed bands is potential ________ A) speed loss B) loss of flexibility C) interference from others D) less-developed standards
C
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
C
To transmit very rapidly in radio, you need ________. A) single-frequency transmission B) single-mode transmission C) wide bandwidth D) narrow bandwidth
C
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
C
We use the terms Wi-Fi and ________ interchangeably in this book. A) 802.1 B) 802.3 C) 802.11 D) 802.1X
C
Which of the following allows access point transmission two wireless clients simultaneously? A) CSMA/CA+ACK B) MIMO C) MU-MIMO D) none of the above
C
Which of the following is true of 802.11ay over 802.11ad? A) greater propagation speed B) greater propagation distance C) both A and B D) neither A nor B
C
Which of the following uses OFDM? A) 802.11ac B) 802.11n C) both A and B D) neither A nor B
C
Wi-Fi Standards come from the ________ Working Group. A) 802.1 B) 802.3 C) 802.11 D) 802.1X
C
Wi-Fi standards use unlicensed bands for ________ A) greater speed B) greater standardization C) greater flexibility D) greater privacy
C
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
D
In CSMA/CA, CS means ________. A) cancel sending B) counter-source C) carriage suspension D) carrier sense
D
In Wi-Fi, 2.4 GHz and 5 GHz refer to ________. A) frequency spectrums B) broadbands C) channels D) none of the above.
D
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
D
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
D
Many 802.11 standards work in the 5 GHz_____. A) licensed spectrum B) unlicensed spectrum C) licensed service band D) unlicensed service band
D
Most wireless systems operate in the ________ range. A) hz B) kHz C) MHz D) GHz
D
Multipath interference is mitigated through ________. A) broadband transmission B) MIMO C) beamforming D) spread spectrum transmission
D
The frequency spectrum extends ________. A) into the gigahertz range B) into the visible light range C) into the ultraviolet range D) to infinity
D
The main problem with the 60 GHz unlicensed band is that ________. A) it cannot be used outside B) it does not support MIMO C) transmission speed is low D) transmission distance is short
D
The most serious problem with wireless transmission in WLANs is ________. A) inverse square law attenuation B) absorptive attenuation C) shadow zones D) multipath interference
D
The set of frequencies used for police communication in a city are ________. A) channels B) frequencies C) spectrums D) none of the above
D
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
D
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
D
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
D
Wi-Fi operates in the 2.4GHz and 5GHz ________. A) frequencies B) spectrums C) channels D) service bands
D
________ 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
D
In a Wi-Fi LAN, wireless hosts generally send frames directly to one another.
FALSE
Within a BSS (and without MU-MIMO), the access point and a wireless host it serves can transmit at the same time.
FALSE
