ch.6 mngt 460
Today, Wi-Fi sales are dominated by ________.
802.11ac
________ is among the most widely used 802.11 transmission standards used today.
802.11ac
Simple installation rules are sufficient to reduce propagation problems to nonissues in ________.
802.3
We use the terms Wi-Fi and ________ interchangeably in this book.
802.11
Most wireless systems operate in the ________ range.
GHz
A single access point, and the set of hosts it serves, is called a(n) ________.
BSS
In roaming, a wireless client moves from one ________ to another without losing its connection.
BSS
The 802.11 standard has two mechanisms for media access control. Of the two, ________ is mandatory.
CSMA/CA+ACK
Which of the following is more efficient and faster?
CSMA/CA+ACK
If two products both comply with 802.11 ac, their performance will always be similar.
False
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
Which of the following allows access point transmission two wireless clients simultaneously?
MU-MIMO
________ is a technique for preventing two wireless stations from interfering with each other by transmitting at the same time.
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.
RTS/CTS
To connect to an access point, you must know its ________.
SSID
Wireless access points typically link wireless clients to ________.
servers on the wired network
Wi-Fi operates in the 2.4GHz and 5GHz ________.
service bands
An 802.11ac Wi-Fi compatibility testing profile contains ________ of the features of the 802.11ac.
some
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.
sometimes true
Multipath interference is mitigated through ________.
spread spectrum transmission
What is the main promise of 802.11ax over 802.11ac?
the ability to serve more users
If you triple channel bandwidth, what happens to the number of channels in a service band?
It is reduced a third.
The set of frequencies used for police communication in a city are ________.
None of these
Access points in the same ESS communicate via ________.
the distribution system
Signals in a transmission usually ________.
Signals in a transmission usually ________.
In general, the fewer the channels, ________.
the greater the likelihood of interference between access points
If an 802.11n client tries to use an 802.11ac access point, ________.
they will communicate using 802.11n
The frequency spectrum extends ________.
to infinity
MIMO ________.
transmits multiple signals in the same channel
Many 802.11 standards work in the 5 GHz_____.
unlicensed service band
In unlicensed bands, ________.
you can use radios wherever you please
WLANs normally use ________.
WLANs normally use ________.
Wi-Fi is a term used by the ________.
Wi-Fi Alliance
________ have SSIDs.
Wireless access points
If a signal has a strength of 100 mW at 10 meters, how strong will it be at 100 meters?
about 0.1
What propagation problem is especially bad in moist air?
absorptive attenuation
Because of ________, an 802.11AX access point can communicate with an 802.11AY client.
backward compatibility
802.11 operates in the ________ unlicensed service band.
both 2.4 MHz and 60 MHz
Which of the following uses OFDM?
both 802.11ac and 802.11n
Media access control governs transmission by ________.
both access points and wireless hosts
As your wireless client travels away from an access point, ________.
both errors begin to increase and your transmission speed decreases
Beamforming can allow an access point to ________.
both focus power on individual clients and send signals to two different clients at the same time
Which of the following is true of 802.11ay over 802.11ad?
both greater propagation speed and greater propagation distance
The term "broadband" is commonly used for ________.
both wide radio bandwidths and high-speed transmission in general
If you want to transmit 7 times as fast in radio, you need to use ________.
channels that are about 7 times as wide
Wider channel bandwidth ________.
increases transmission speed
Two access points that operate on the same channel will ________.
interfere
The downside of unlicensed bands is potential ________
interference from others
Companies prefer the 5 GHz band because there is ________ than in the 2.5 GHz band.
more bandwidth
Spread spectrum transmission is used in WLANs for ________.
more reliable transmission
Channels with wide bandwidths are called ________ channels.
broadband
To transmit data very rapidly, you would want a ________ channel.
broadband
The most serious problem with wireless transmission in WLANs is ________.
multipath interference
Wi-Fi standards use unlicensed bands for ________
greater flexibility
Frequency is measured in terms of ________.
hertz
Spread spectrum transmission is used in WLANs because ________.
it is required by regulators
When a receiver transmits an ACK, ________.
it must transmit immediately
In an extended service set, each access point ________.
must have the same SSID
What propagation problem becomes worse as frequency increases?
neither inverse square law attenuation nor electromagnetic interference
Wi-Fi normally uses a(n) ________.
omnidirectional antenna
When does it make sense to use RTS/CTS?
when not all of the devices can hear each other
To transmit very rapidly in radio, you need ________.
wide bandwidth
Compared to wired transmission, propagation problems in radio transmissions are ________.
worse
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?
1
Wi-Fi Standards come from the ________ Working Group.
802.11
