Chapter 6
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
A
14) What propagation problem becomes worse as frequency increases? A) Absorptive attenuation. B) Electromagnetic interference. C) Both A and B D) Neither A nor B
A
19) To handle multiple conversations in radio transmission, you use multiple ________. A) channels B) frequencies C) service bands D) wires
A
2) Wireless network standards come from ________. A) OSI B) TCP/IP C) Both A and B D) Neither A nor B
A
29) If a radio transmission is easily blocked by obstacles, then you need to maintain ________. A) a clear line of sight B) spread spectrum transmission interference C) broadband transmission D) deep transmission
A
31) 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
32) Interference is minimized in ________. A) licensed bands B) unlicensed bands
A
35) 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
A
36) 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.
A
39) 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
46) 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
48) An 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
54) 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
55) The standard for roaming among access points is ________. A) 802.11r B) 802.11s C) 802.11W D) None of the above
A
56) 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.
A
57) There is an access point that serves eight wireless hosts. On how many channels will these devices transmit during the course of an hour or two? A) 1 B) 2 C) 7 D) 8
A
66) CSMA/CA+ACK usually is ________. A) required B) optional
A
67) 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
A
68) Which of the following is more efficient? A) CSMA/CA+ACK. B) RTS/CTS. C) Both are about equally efficient.
A
73) Which of the following brings gigabit speeds to clients? A) 802.11ac B) 802.11g C) 802.11n D) None of the above
A
74) For wireless backup, which of the following is adequate? A) 802.11ac B) 802.11g C) 802.11n D) All of the above
A
75) Which of the following uses OFDM? A) 802.11g B) 802.11ac C) Both A and B D) Neither A nor B
A
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
A
77) Which of the following can operate in the 5 GHz band? A) 802.11g B) 802.11ac C) Both A and B D) Neither A nor B
A
8) Cellular telephony uses ________. A) an omnidirectional antenna B) a dish antenna C) Both A and B D) Neither A nor B
A
82) MIMO ________. A) increases throughput B) lowers propagation distance C) Both A and B D) Neither A nor B
A
83) Beamforming can ________. A) direct signal strength at individual wireless hosts B) transmit multiple spatial data streams in the same channel C) Both A and B D) Neither A nor B
A
85) Traditional MIMO can ________ A) send multiple signals in the same channel B) send signals to two different clients at the same time C) Both A and B D) Neither A nor B
A
88) If more users move to an access point, this decreases ________. A) individual throughput B) aggregate throughput C) Both A and B D) Neither A nor B
A
91) If an 802.11n access point and an 802.11g client communicate, they communicate using ________. A) 802.11g B) 802.11n C) Either A or B D) Neither A nor B
A
94) 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
95) The 802.11 standard for mesh networking is ________. A) 802.11m B) 802.11r C) 802.11ac D) None of the above
A
10) Attenuation with distance is faster with ________. A) UTP transmission B) radio transmission C) Both A and B D) Neither A nor B
B
20) Signals usually ________. A) travel at a single frequency B) spread over a range of frequencies
B
24) To transmit data very rapidly, you would want a ________ channel. A) narrowband B) broadband C) single-frequency band D) Any of the above
B
26) 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
B
30) WLANs normally use ________. A) licensed bands B) unlicensed bands
B
37) The 2.4 GHz band supports ________ nonoverlapping 20 MHz channel(s). A) 1 B) 3 C) 7 D) 11
B
4) Wireless access points typically link wireless clients to ________. A) wireless servers B) servers on the wired network C) Both A and B
B
40) Spread spectrum transmission is used in WLANs for ________. A) higher transmission speed B) more reliable transmission C) greater security D) All of the above
B
44) 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
B
47) 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
49) The ________ is the identifier in a basic service set. A) BSS B) BSSID C) SSID
B
5) Wireless radio transmission usually is expressed in terms of ________. A) wavelength B) frequency C) Both A and B D) Neither A nor B
B
6) Frequency is measured in terms of ________. A) nanometers B) hertz C) Both A and B D) Neither A nor B
B
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.
B
64) CSMA/CA+ACK is ________. A) efficient B) inefficient
B
7) The other wireless device is far away in a known direction. You should use ________. A) an omnidirectional antenna B) a dish antenna C) Both A and B D) Neither A nor B
B
72) For which of the following is 100 meters a typical service distance? A) 802.11g. B) 802.11n. C) Both A and B D) Neither A nor B
B
78) 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
79) 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
B
87) In 802.11 networks, the speed I receive on my portable devices is a(n) ________. A) aggregate throughput B) individual throughput C) rated speed D) None of the above
B
15) What propagation problem becomes worse as frequency increases? A) Absorptive attenuation. B) Shadow zones. C) Both A and B D) Neither A nor B
C
22) To transmit very rapidly in RADIO, you need ________. A) single-frequency transmission B) single-mode transmission C) wide bandwidth D) narrow bandwidth
C
23) Channels with wide bandwidths are called ________ channels. A) multimode B) full-duplex C) broadband D) modulated
C
27) 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
C
3) Wireless LAN standards are created by the ________ Working Group. A) 802.1 B) 802.3 C) 802.11 D) 802.3W
C
33) 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
34) In 802.11, channel bandwidth usually is ________. A) 20 GHz B) 40 GHz C) 20 MHz D) 40 MHz
C
42) 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
43) Which of the following uses OFDM? A) 802.11g. B) 802.11n. C) Both A and B D) Neither A nor B
C
51) 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
C
53) 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
60) Media access control governs transmission by ________. A) access points B) wireless hosts C) Both A and B D) Neither A nor B
C
84) 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
12) 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
13) 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
16) The frequency spectrum extends ________. A) into the gigahertz range B) into the visible light range C) into the ultraviolet range D) to infinity
D
17) 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
D
21) 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
28) 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
D
38) The 5 GHz band supports about ________ nonoverlapping 20 MHz channel(s). A) 1 B) 3 C) 6 D) 12
D
50) To connect to an access point, you must know its ________. A) BSS B) DSS C) ESS D) None of the above
D
58) ________ 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
65) 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
69) Which of the following is a full, according to the book? A) 802.11ac. B) 802.11ad. C) Both A and B D) Neither A nor B
D
70) 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
D
71) For which standard is 300 Mbps a typical rated speed? A) 802.11ac. B) 802.11ad. C) 802.11g. D) 802.11n.
D
80) 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
D
92) Using unused transmission channels in a service band is called using ________. A) dark spectrum B) a smart antenna C) opportunistic agility D) white space
D
93) Two wireless devices communicate via Wi-Fi Direct using ________. A) an access point that lets them talk directly B) an Ethernet network to connect their access points C) Either A or B D) Neither A nor B
D
11) If the signal strength at 20 meters is 90 mW, the signal strength at 60 meters would be 10 mW.
FALSE
18) The terms channel and service band mean roughly the same thing.
FALSE
41) Spread spectrum transmission is used in commercial WLANs for security reasons.
FALSE
45) Access points take frames from wireless devices and send these frames on to devices on the wired LAN.
FALSE
59) An access point and a host it serves can transmit to each other simultaneously.
FALSE
9) Radio has more reliable transmission than UTP.
FALSE
96) Two WLAN products that conform to the same standard will have almost equal performance.
FALSE
25) Networks that are fast are often called broadband whether or not they use radio channels.
TRUE
52) In 802.11 WLANs, the terms handoff and roaming mean the same thing.
TRUE
62) When a wireless NIC using CSMA/CD receives a frame correctly, it immediately sends back a reply without listening for traffic.
TRUE
63) CSMA/CA+ACK is reliable.
TRUE
81) MIMO allows you to transmit two signals in the same channel.
TRUE
86) Another name for beamforming is having a smart antenna.
TRUE
89) As a station moves away from an access point, the access point transmits more slowly to it.
TRUE
90) The presence of a client that is distant from the access point reduces the individual throughput of other clients served by that access point.
TRUE
97) If a wireless client only has two MIMO antennas, an access point with three MIMO antennas will produce better performance than an access point with two MIMO antennas.
TRUE
