Chapter 6 Test 2
A cellular telephone uses a(n) ________. A) omnidirectional antenna
A
A single access point and the set of hosts it serves is called a(n) ________. A) BSS
A
CSMA/CA+ACK usually is ________. A) mandatory
A
Companies are moving to the 5 GHz band because there is ________ than in the 2.5 GHz band. A) more bandwidth
A
Compared to wired transmission, propagation problems in radio transmission are ________. A) worse
A
In an extended service set, each access point ________. A) must have the same SSID
A
In unlicensed bands, ________. A) you can use radios wherever you please
A
MIMO ________. A) increases throughput
A
Spread spectrum transmission is used in WLANs because ________. A) it is required by regulators
A
The standard for roaming among access points is ________. A) 802.11r
A
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
A
To connect to an access point, you must know its ________. A) SSID
A
To handle multiple conversations in radio transmission, you normally use multiple ________. A) channels
A
To use an access point, you need to know its ________. A) SSID
A
What happens if two nearby access points use the same channel? A) They will interfere with each other.
A
What propagation problem is especially bad in moist air? A) absorptive attenuation
A
Which of the following is more efficient and faster? A) CSMA/CA+ACK
A
Which of the following is the newest Wi-Fi standard? A) 802.11ac
A
Wider channel bandwidth ________. A) increases transmission speed
A
Wireless network standards are ________ standards. A) OSI
A
Wireless network standards operate at ________. A) the data link layer
A
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? B) 2
B
Access points in the same ESS communicate via ________. B) the distribution system
B
CSMA/CD+ACK is ________. B) reliable
B
Frequency is measured in terms of ________. B) hertz
B
In the 5 GHz band, how many channels can you have with 802.11ac with 80 GHz channels? B) 6
B
Signals in a transmission usually ________. B) spread over a range of frequencies
B
Spread spectrum transmission is used in WLANs for ________. B) more reliable transmission
B
The 2.4 GHz band supports ________ possible non-overlapping 20 MHz channel(s). B) 3
B
The 802.11 standard has two mechanisms for media access control. One of two mechanisms is mandatoryit is ________. B) CSMA/CA+ACK
B
The other wireless device is far away in a known direction. It would be better to use ________. B) a dish antenna
B
To transmit data very rapidly, you would want a ________ channel. B) broadband
B
WLANs normally use ________. B) unlicensed bands
B
What propagation problem becomes worse as there is a large and dense object between sender and receiver? B) shadow zones or dead zones
B
Which of the following only operates in the 5 GHz band? B) 802.11ac
B
Wireless access points typically link wireless clients to ________. B) servers on the wired network
B
Wireless radio transmission speed is usually measured in terms of ________. B) frequency
B
________ have SSIDs. B) Wireless access points
B
802.11 standards are being developed to work in the ________ unlicensed band. A) 2.4 GHz B) 5 GHz C) both A and B
C
A channel has more bandwidth than is necessary given data transmission speeds requirements in ________ transmission. C) spread spectrum
C
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
C
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
C
Channels with wide bandwidths are called ________ channels. C) broadband
C
In 802.11g, channel bandwidth usually is ________. C) 20 MHz
C
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. C) always false
C
Media access control governs transmission by ________. A) access points B) wireless hosts C) both A and B
C
Radio transmission is measured in terms of ________. C) frequency
C
To transmit very rapidly in RADIO, you need ________. C) wide bandwidth
C
We use the terms Wi-Fi and ________ interchangeably in this book. C) 802.11
C
Which of the following uses OFDM? A) 802.11ac B) 802.11n C) both A and B
C
Wi-Fi Standards come from the ________ Working Group. C) 802.11
C
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
At 10 meters, a signal has a strength of 100 mW. About how strong will it be at 40 meters? D) about 6 mW
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. D) RTS/CTS
D
MIMO ________. D) transmits multiple signals in the same channel
D
The 5 GHz band usually supports about ________ non-overlapping 20 MHz channel(s). D) 12
D
The frequency spectrum extends ________. D) to infinity
D
The most serious problem with wireless transmission in WLANs is ________. D) multipath interference
D
Today, Wi-Fi sales are dominated by ________. D) 802.11ac
D
What propagation problem becomes worse as frequency increases? D) neither A nor B
D
________ is a technique for preventing two wireless stations from transmitting at the same time and therefore interfering with each other. D) Media access control
D
Access points take ________ from wireless devices and send them on to devices on the wired LAN. They also do the converse. A) packets
A
2.4 GHz and 5 GHz are ________. D) service bands
D
