OMIS 460 CH 6
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) 1
Which of the following is the newest Wi-Fi standard? A) 802.11ac B) 802.11g C) 802.11n D) 802.11b
A) 802.11ac
The standard for roaming among access points is ________. A) 802.11r B) 802.11s C) 802.11W D) the wireless handoff protocol
A) 802.11r
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) BSS
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) CSMA/CA+ACK
Wireless network standards are ________ standards. A) OSI B) TCP/IP C) both A and B
A) OSI
To connect to an access point, you must know its ________. A) SSID B) EUI-48 address C) IP address D) Wi-Fi ID
A) SSID
To use an access point, you need to know its ________. A) SSID B) BSSID C) ESSID D) Wi-Fi ID
A) SSID
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.
A) They will interfere with each other.
What propagation problem is especially bad in moist air? A) absorptive attenuation B) electromagnetic interference C) multipath interference D) inverse square law attenuation
A) absorptive attenuation
To handle multiple conversations in radio transmission, you normally use multiple ________. A) channels B) frequencies C) service bands D) wires
A) channels
MIMO ________. A) increases throughput B) lowers propagation distance C) both A and B D) neither A nor B
A) increases throughput
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
A) increases transmission speed
If more users move to an access point, this decrease ________. A) individual throughput B) aggregate throughput C) both A and B D) neither A nor B
A) individual throughput
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) it is required by regulators
CSMA/CA+ACK usually is ________. A) mandatory B) optional C) not important D) efficient
A) mandatory
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
A) more bandwidth
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
A) must have the same SSID
A cellular telephone uses a(n) ________. A) omnidirectional antenna B) dish antenna C) both A and B D) neither A nor B
A) omnidirectional antenna
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
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
A) packets
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) the data link layer
Compared to wired transmission, propagation problems in radio transmission are ________. A) worse B) about as bad C) better
A) worse
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) you can use radios wherever you please
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) 2
The 2.4 GHz band supports ________ possible non-overlapping 20 MHz channel(s). A) 1 B) 3 C) 7 D) 11
B) 3
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
B) 6
Which of the following only operates in the 5 GHz band? A) 802.11b B) 802.11ac C) 802.11g D) 802.11n
B) 802.11ac
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
B) CSMA/CA+ACK
________ have SSIDs. A) Wireless clients B) Wireless access points C) both A and B D) neither A nor B
B) Wireless access points
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
B) a dish antenna
To transmit data very rapidly, you would want a ________ channel. A) narrowband B) broadband C) single-frequency band D) none of the above
B) broadband
Wireless radio transmission speed is usually measured in terms of ________. A) wavelength B) frequency C) amplitude D) wetness
B) frequency
Frequency is measured in terms of ________. A) nanometers B) hertz C) microns D) microseconds
B) hertz
Spread spectrum transmission is used in WLANs for ________. A) higher transmission speed B) more reliable transmission C) greater security D) more efficient transmission
B) more reliable transmission
CSMA/CD+ACK is ________. A) unreliable B) reliable C) semireliable
B) reliable
Wireless access points typically link wireless clients to ________. A) wireless servers B) servers on the wired network C) both A and B
B) servers on the wired network
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
B) shadow zones or dead zones
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 over a range of frequencies
Access points in the same ESS communicate via ________. A) wireless transmission B) the distribution system C) a master access point D) routers
B) the distribution system
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) they will communicate using 802.11n
WLANs normally use ________. A) licensed bands B) unlicensed bands C) both A and B D) neither A or B
B) unlicensed bands
In 802.11g, channel bandwidth usually is ________. A) 20 GHz B) 40 GHz C) 20 MHz D) 40 MHz
C) 20 MHz
We use the terms Wi-Fi and ________ interchangeably in this book. A) 802.1 B) 802.3 C) 802.11 D) 802.1X
C) 802.11
Wi-Fi Standards come from the ________ Working Group. A) 802.1 B) 802.3 C) 802.11 D) 802.1X
C) 802.11
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) Multiuser MIMO
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
C) always false
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
C) both A and B
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
C) both A and B
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
C) both A and B
Media access control governs transmission by ________. A) access points B) wireless hosts C) both A and B D) neither A nor B
C) both A and B
Which of the following uses OFDM? A) 802.11ac B) 802.11n C) both A and B D) neither A nor B
C) both A and B
Channels with wide bandwidths are called ________ channels. A) multimode B) full-duplex C) broadband D) parallel
C) broadband
Radio transmission is measured in terms of ________. A) bytes per second B) wavelength C) frequency D) bits per second
C) frequency
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
C) spread spectrum
To transmit very rapidly in RADIO, you need ________. A) single-frequency transmission B) single-mode transmission C) wide bandwidth D) narrow bandwidth
C) wide bandwidth
The 5 GHz band usually supports about ________ non-overlapping 20 MHz channel(s). A) 1 B) 3 C) 7 D) 12
D) 12
Today, Wi-Fi sales are dominated by ________. A) 802.11a B) 802.11g C) 802.11n D) 802.11ac
D) 802.11ac
The 802.11 standard for mesh networking is ________. A) 802.11m B) 802.11r C) 802.11ac D) 802.11s
D) 802.11s
________ 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
D) Media access control
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) RTS/CTS
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
D) about 6 mW
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) multipath interference
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) neither A nor B
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
D) none of the above
2.4 GHz and 5 GHz are ________. A) frequency spectrums B) broadbands C) channels D) service bands
D) service bands
The frequency spectrum extends ________. A) into the gigahertz range B) into the visible light range C) into the ultraviolet range D) to infinity
D) to infinity
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) transmits multiple signals in the same channel
If two products both comply with 802.11 ac, they should have close to the same performance.
False
