6, 7, 8 Flashcards
Which technology has a greater tolerance of delay spread?
A. DSSS
B. FHSS
C. OFDM
D. HR-DSSS
C. OFDM
Which is often used to describe the “shape” of a frequency channel? (Choose all that apply.)
A. Maximum spectral density
B. Transmit spectral mask
C. Radio spectrum
D. Spectrum mask
B. Transmit spectral mask
D. Spectrum mask
Which term best describes modulation accuracy?
A. EVM
B. ERP
C. VHT
D. QAM
A. EVM
Error vector magnitude (EVM) is a measure used to quantify the performance of a radio
receiver or transmitter in regard to modulation accuracy.
802.11n (HT radios) can transmit in which frequency bands? (Choose all that apply.)
A. 2.4 GHz–2.4835 GHz
B. 5.47 GHz–5.725 GHz
C. 902 GHz–928 GHz
D. 5.15 GHz–5.25 GHz
A. 2.4 GHz–2.4835 GHz
B. 5.47 GHz–5.725 GHz
D. 5.15 GHz–5.25 GHz
Odd one out.
A 20 MHz OFDM channel uses how many 312.5 KHz subcarriers to modulate data when transmitted by an 802.11a/g radio?
A. 64
B. 52
C. 48
D. 36
C. 48
Which of these client radios will be able to transmit in the U-NII-5 band?
A. Wi-Fi 4 client radios
B. Wi-Fi 5 client radios
C. Wi-Fi 6 client radios
D. Wi-Fi 6E client radios
E. Wi-Fi 7 client radios
D. Wi-Fi 6E client radios
What is the frequency width of a standard OFDM channel?
A. 20 MHz
B. 22 MHz
C. 25 MHz
D. 40 MHz
E. 80 MHz
F. 160 MHz
A. 20 MHz
What best describes hop time?
A. The period of time that the transmitter waits before hopping to the next frequency
B. The period of time that the standard requires when hopping between frequencies
C. The period of time that the transmitter takes to hop to the next frequency
D. The period of time that the transmitter takes to hop through all the FHSS frequencies
C. The period of time that the transmitter takes to hop to the next frequency
As defined by the IEEE 802.11-2020 standard, how much separation is needed between center frequencies of channels in the U-NII-2C band?
A. 10 MHz
B. 20 MHz
C. 22 MHz
D. 25 MHz
E. 30 MHz
B. 20 MHz
Which of these 802.11 technologies can operate in the 5 GHz frequency band? (Choose all that apply.) 4
A. 802.11a (OFDM radios)
B. 802.11b (HR-DSSS radios)
C. 802.11g (ERP radios)
D. 802.11n (HT radios)
E. 802.11ac (VHT radios)
F. 802.11ax (HE radios)
A. 802.11a (OFDM radios)
D. 802.11n (HT radios)
E. 802.11ac (VHT radios)
F. 802.11ax (HE radios)
No DSSS or ERP (b g)
Which U-NII band is currently designated for possible wireless communications of an automotive intelligent transportation system (ITS)?
A. U-NII-1
B. U-NII-2A
C. U-NII-2B
D. U-NII-2C
E. U-NII-3
F. U-NII-4
F. U-NII-4
When data is corrupted by previous data from a reflected signal, this is known as what?
A. Delay spread
B. Intersymbol interference
C. Co-channel interference
D. Adjacent cell interference
B. Intersymbol interference
Assuming all channels are supported by a 5 GHz access point, how many possible 20 MHz channels can be configured on the access point?
A. 4
B. 11
C. 12
D. 25
D. 25
Which of these technologies is the most resilient against the negative effects of multipath?
A. FHSS
B. DSSS
C. HR-DSSS
D. OFDM
D. OFDM
What is the average amount of aggregate throughput at any data rate when legacy 802.11a/b/g/n/ac radios are transmitting?
A. 80 percent
B. 75 percent
C. 50 percent
D. 100 percent
C. 50 percent
Which of these 802.11 technologies can operate in the 2.4 GHz frequency band? (Choose all that apply.) 4
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A. 802.11a (OFDM radios)
B. 802.11b (HR-DSSS radios)
C. 802.11g (ERP radios)
D. 802.11n (HT radios)
E. 802.11ac (VHT radios)
F. 802.11ax (HE radios)
B. 802.11b (HR-DSSS radios)
C. 802.11g (ERP radios)
D. 802.11n (HT radios)
F. 802.11ax (HE radios)
No VHT or OFDM (a ac)
In the United States, 802.11 radios were not allowed to transmit on which range of frequencies in order to avoid interference with Terminal Doppler Weather Radar (TDWR) systems?
A. 5.15 GHz–5.25 GHz
B. 5.25 GHz–5.25 GHz
C. 5.60 GHz–5.65 GHz
D. 5.85 GHz–5.925 GHz
C. 5.60 GHz–5.65 GHz
Which modulation types are used by OFDM technology? (Choose all that apply.)
A. QAM
B. Phase
C. Frequency
D. Hopping
A. QAM
B. Phase
The Barker code converts a bit of data into a series of bits that are referred to as what?
A. Chipset
B. Chips
C. Convolutional code
D. Complementary code
B. Chips
Which technology will be needed in the U-NII-5 and U-NII-6 bands to prevent APs from interfering with incumbents in 6 GHz?
A. DFS
B. AFC
C. TPC
D. QAM
B. AFC
The logical name of an 802.11 wireless network is known as which type of address? (Choose all that apply.) 2
A. BSSID
B. MAC address
C. IP address
D. SSID
E. ESSID
D. SSID
E. ESSID
Which two 802.11 topologies require the use of an AP?
A. IBSS
B. BSS
C. PBSS
D. ESS
B. BSS
D. ESS
The 802.11 standard defines which medium to be used in a distribution system?
A. 802.3 Ethernet
B. 802.4 Token bus
C. 802.5 Token ring
D. 802.8 Fiber optic
E. 802.16 WiMAX
F. None of the above
F. None of the above
Which option is a wireless computer topology used for communication between computer devices within close proximity of a person?
A. WWAN
B. WMAN
C. WLAN
D. WPAN
D. WP(erson)AN
Which 802.11 service set facilitates roaming for Wi-Fi client devices?
A. ESS
B. BSS
C. IBSS
D. PBSS
A. ESS
What factors might affect the size of a basic service area (BSA) of an AP? (Choose all that apply.) 3
A. Antenna gain
B. CSMA/CA
C. Transmission power
D. Indoor/outdoor surroundings
E. Distribution system
A. Antenna gain
C. Transmission power
D. Indoor/outdoor surroundings
Granted that many enterprise Wi-Fi vendors support the transmission of multiple SSIDs and effectively multiple BSSs from a single AP radio, which of these statements are true? (Choose all that apply.)
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A. When creating multiple SSIDs, the existence of multiple basic service sets (BSSs) results in excessive amounts of MAC layer overhead.
B. The maximum number of SSIDs and matching basic service sets per transmitting radio is 8.
C. When creating multiple SSIDs, the existence of multiple basic service sets (BSSs) provides more airtime and greater performance.
D. The maximum number of SSIDs and matching basic service sets per transmitting radio is 16.
E. The maximum number of SSIDs and matching basic service sets per transmitting radio is vendor specific.
A. When creating multiple SSIDs, the existence of multiple basic service sets (BSSs) results in excessive amounts of MAC layer overhead.
E. The maximum number of SSIDs and matching basic service sets per transmitting radio is vendor specific.
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MAC overhead, vendor specific
Which terms describe an 802.11 topology involving STAs but no access points? (Choose all that apply.)
A. BSS
B. Ad hoc
C. DSSS
D. Infrastructure
E. IBSS
F. Peer-to-peer
B. Ad hoc
E. IBSS
F. Peer-to-peer
802.11 client STAs operating in the default infrastructure mode within a normal BSS may communicate in which of the following scenarios? (Choose all that apply.) 3
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A. 802.11 frame exchanges with other 802.11 client STAs via an AP
B. 802.11 frame TDLS exchanges directly with other client STAs within the BSSs
C. 802.11 frame IBSS exchanges directly with other client STAs within the BSS
D. Frame exchanges with network devices on the DSM
E. All of the above
A. 802.11 frame exchanges with other 802.11 client STAs via an AP
B. 802.11 frame TDLS exchanges directly with other client STAs within the BSSs
D. Frame exchanges with network devices on the DSM
Everything but IBSS.
Which of the following are included in the topologies defined by the 802.11-2020 standard?
(Choose all that apply.) 4
A. DSSS
B. ESS
C. BSS
D. IBSS
E. FHSS
F. PBSS
B. ESS
C. BSS
D. IBSS
F. PBSS
All the Bs and one E.
Which wireless topology provides citywide wireless coverage?
A. WMAN
B. WLAN
C. WPAN
D. WAN
E. WWAN
A. WMAN
A wireless metropolitan area network (WMAN) provides coverage to a metropolitan area,
such as a city and the surrounding suburbs.
At which layer of the OSI model is a BSSID address used?
A. Physical
B. Network
C. Session
D. Data-Link
E. Application
D. Data-Link
The BSSID (THREE!!) address can be found in which topologies? (Choose all that apply.) 3
A. FHSS
B. IBSS
C. ESS
D. HR-DSSS
E. BSS
B. IBSS
C. ESS
E. BSS
Nothing with an H is involved.
Which 802.11 service set defines mechanisms for mesh networking?
A. BSS
B. PBSS
C. ESS
D. MBSS
E. IBSS
D. M(esh)BSS
Which 802.11 service set is defined specifically for directional multi-gigabit (DMG) radios?
A. BSS
B. ESS
C. IBSS
D. PBSS
E. MBSS
D. PBSS
The 802.11-2020 standard specifies architectural services that stations use within various m802.11 topologies.
Which service is used by both client stations and AP stations?
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A. Station service
B. Distribution service
C. PBSS control point service
D. Integration service
E. Bus service
A. Station service
A network consisting of clients and two or more APs with the same SSID connected by an 802.3 Ethernet backbone is one example of which 802.11 topology? (Choose all that apply.)
A. Public basic service set
B. Basic service set
C. Extended service set
D. Independent basic service set
E. Ethernet service set
C. Extended service set
Which term best describes two access points communicating with each other wirelessly while also allowing clients to communicate through the access points?
A. WDS
B. DS
C. DSS
D. DSSS
E. DSM
A. WDS
What components make up a distribution system? (Choose all that apply.)
A. HR-DSSS
B. DSS
C. DSM
D. DSSS
E. QBSS
B. DSS
C. DSM
What type of wireless topology is defined by the 802.11-2020 standard?
A. WAN
B. WLAN
C. WWAN
D. WMAN
E. WPAN
B. WLAN
Which medium contention and access method is used as the foundation of 802.11 Distributed Coordination Function (DCF)?
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A. Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
B. Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)
C. Token passing
D. Demand priority
B. Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)
802.11 collision detection is achieved using which technology?
A. Network allocation vector (NAV)
B. Clear channel assessment (CCA)
C. Duration/ID value
D. Receiving an ACK from the destination station
E. Positive collision detection cannot be determined.
E. Positive collision detection cannot be determined.
ACK and CTS frames follow which interframe space?
A. EIFS
B. DIFS
C. PIFS
D. SIFS
E. AIFS
D. SIFS
The carrier sense portion of CSMA/CA is performed by using which of the following methods? (Choose all that apply.) 2
A. Contention window
B. Backoff timer
C. Channel sense window
D. Clear channel assessment
E. NAV timer
D. Clear channel assessment
E. NAV timer
After the station has performed the carrier sense and determined that no other devices are transmitting for a period of a DIFS interval, what is the next step for the station?
A. Wait the necessary number of slot times before transmitting if a random backoff value has already been selected.
B. Begin transmitting.
C. Select a random backoff value.
D. Begin the random backoff timer.
C. Select a random backoff value.
Physical carrier sense uses which two thresholds during the clear channel assessment to determine if the medium is busy?
A. RF detect
B. Signal detect
C. Transmission detect
D. Energy detect
E. Random detect
B. Signal detect
D. Energy detect
Which of the following terms are affiliated with the virtual carrier sense mechanism?
(Choose all that apply.) 2
A. Contention window
B. Network allocation vector
C. Random backoff time
D. Duration/ID field
B. Network allocation vector
D. Duration/ID field
The goal of allocating equal time as opposed to equal opportunity is known as what?
A. Access fairness
B. Opportunistic medium access
C. CSMA/CA
D. Airtime fairness
D. Airtime fairness
CSMA/CA and DCF define which mechanisms that attempt to ensure that only one 802.11 radio can transmit on the half-duplex RF medium? (Choose all that apply.)
A. Pseudo-random backoff timer
B. Virtual carrier sense
C. Collision detection
D. Physical carrier sense
E. Interframe spacing
A. Pseudo-random backoff timer
B. Virtual carrier sense
D. Physical carrier sense
E. Interframe spacing
There is no collision detection.
The Wi-Fi Alliance certification called Wi-Fi Multimedia (WMM) is based on which wireless medium access method defined by the 802.11-2020 standard?
A. DCF
B. EDCA
C. HCCA
D. HSRP
B. EDCA
Hybrid Coordination Function (HCF) defines what allotted period of time in which a station can transmit multiple frames?
A. Target wake time
B. Airtime fairness
C. Random backoff timer
D. NAV timer
E. Transmit opportunity
E. Transmit opportunity
WMM is based on EDCA and provides for traffic prioritization via which of the following access categories? (Choose all that apply.)
A. WMM Voice priority
B. WMM Video priority
C. WMM Audio priority
D. WMM Best Effort priority
E. WMM Background priority
A. WMM Voice priority
B. WMM Video priority
D. WMM Best Effort priority
E. WMM Background priority
No audio priority.
As defined by WMM, which type of application traffic has the highest priority for transmission on the half-duplex RF medium?
A. Best Effort
B. Video
C. Voice
D. Background
C. Voice
What information that comes from the wired network is used to assign traffic into access categories on an access point?
A. Duration/ID
B. 802.1D priority tags
C. Destination MAC address
D. Source MAC address
B. 802.1D priority tags
What are the two reasons that 802.11 radios use physical carrier sense? (Choose all that apply.) 2
A. To synchronize incoming transmissions
B. To synchronize outgoing transmissions
C. To reset the NAV
D. To start the random backoff timer
E. To assess the RF medium
A. To synchronize incoming transmissions
E. To assess the RF medium
Which carrier sense method is used to detect and decode 802.11 transmissions?
A. Network allocation vector
B. Signal detect
C. Energy detect
D. Virtual carrier sense
B. Signal detect
Which field in the MAC header of an 802.11 frame resets the NAV timer for all listening 802.11 stations?
A. QoS control
B. Frame control
C. Duration/ID
D. Sequence number
E. Retry
C. Duration/ID
The EDCA medium access method provides for the prioritization of traffic via priority queues that are matched to eight 802.1D priority tags. What are the EDCA priority queues called?
A. Traffic streams
B. Access categories
C. Priority levels
D. Priority bits
E. Access levels
B. Access categories
ACKs are required for which of the following frames?
A. Unicast
B. Broadcast
C. Multicast
D. Anycast
A. Unicast
Which two components of the pseudo-random backoff algorithm are used to create the pseudo-random backoff timer?
A. Contention window
B. Network allocation vector
C. Duration/ID
D. Slot time
A. Contention window
D. Slot time
Window and slot are related.
