CWNA-108 Practice Test 2 Flashcards
When an RF wave encounters obstacles smaller than the wavelength and reflective in nature, what is likely to occur?
Warping
Refraction
Scattering
Reflection
Scattering
What is the term used when measuring return loss caused by mismatched impedance in RF cables and connectors?
Attenuation Factor
EIRP
IR
VSWR
VSWR (Voltage Standing Wave Ratio)
What metric ultimately determines the data rate that can be achieved between an AP and a STA?
Noise floor
Signal strength
SNR
Beacon rate
SNR (Signal-to-Noise-Ratio)
What is the output of a link budget?
Total Cost of Ownership (TCO)
Signal-to-Noise-Ratio (SNR)
System Operating Margin (SOM)
System Cost (SC)
System Operating Margin (SOM)
A WLAN transmitter that emits a 20 mW signal is connected to a cable with 6 dB loss. If the cable is connected to an antenna with 12 dBi gain, what is the EIRP at the antenna element?
120 mW
80 mW
5 mW
320 mW
80 mW
Why are some WLAN client devices able to receive signals at given data rates that are weaker than other client devices can receive?
The receive sensitivity is better on some devices than others.
The output power is higher on some devices than others.
The device drivers are coded according to better programming practices.
The VSWR is higher on devices that can receive weaker signals.
The receive sensitivity is better on some devices than others.
What term describes an RF transmission system up to but not including the antenna?
EIRP
Chipset
Intentional Radiator
Radio
Intentional Radiator
What kind of MIMO antennas are typically used for WLAN deployments when the antennas are placed central to the target coverage area?
Omni-directional
Patch
Panel
Grid
Omni-directional
What statement about the beamwidth of an RF antenna is true?
Beamwidth has no impact on the propagation pattern.
Horizontal beamwidth is displayed on the Elevation chart.
As the gain of the antenna increases, the beamwidth decreases in either the horizontal or vertical direction or both.
The horizontal and vertical beamwidth are measured where the main lobe loses 6 dB of power.
As the gain of the antenna increases, the beamwidth decreases in either the horizontal or vertical direction or both.
What is true about WPA in 802.11 wireless networks?
When WPA is used, 802.11n and 802.11ac devices fall back to 54 Mbps as the highest data rate.
WPA is based on CCMP/AES and is non-deprecated in the 802.11-2016 standard.
WPA is based on TKIP/RC4 and is non-deprecated in the 802.11-2016 standard.
WPA implements AES encryption in the same way that WEP does.
When WPA is used, 802.11n and 802.11ac devices fall back to 54 Mbps as the highest data rate.
When an 802.11 amendment is ratified, what happens to the standard?
The standard includes the specifications of the amendment even though they are not included in a rollup update initially.
The amendment specifications are optional and never become part of a rollup update.
Amendments are created to resolve errors in the standard and introduce no new features.
Device manufacturers must wait until the next rollup to include the amendment specifications in chipsets and drivers.
The standard includes the specifications of the amendment even though they are not included in a rollup update initially.
You are implementing a VHT-capable AP. When operating in VHT mode, which one of the following channels is not available for use by the AP?
56
144
6
153
6
What statement is true regarding the use of the ERP PHY in 802.11 networks?
ERP uses 256-QAM modulation to achieve the maximum data rate of 54 Mbps.
ERP operates only in the 2.4 GHz band and supports a maximum data rate of 54 Mbps.
ERP is identical to OFDM PHY, except it operates in the 5 GHz band whereas OFDM operates in the 2.4 GHz band.
ERP operates in either 2.4 GHz or 5 GHz and supports a maximum data rate of 54 Mbps.
Feedback
ERP operates only in the 2.4 GHz band and supports a maximum data rate of 54 Mbps.
Which IEEE 802.11 Physical Layer (PHY) supports frequency use below 1 GHz and is optimal for low data rate long range communications?
DMG
S1G
VHT
HT
S1G
An 802.11-based network includes two laptops, one mobile phone, and one tablet. No AP is involved in the communications. What WLAN use case is described?
WWAN
ESS
IBSS
BSS
IBSS
What is defined as a system used to interconnect a set of BSSs and integrated LANs to create an ESS?
WM (Wireless Medium)
DS (Distribution System)
STA (station)
DFS (Dynamic Frequency Selection)
DS (Distribution System)
When a controller-based WLAN is in use and roaming is desired with 802.1X/EAP, what solution may be used to implement fast and secure roaming?
OKC
TPC
WMM
DFS
OKC (Opportunistic Key Caching)
What can a client device use to determine whether a BSS supports WMM QoS capabilities?
QoS Query frames
Beacon frame information
Data frame analysis of existing associated STAs
Control frame analysis of existing associated STAs
Beacon frame information
How can a transmitting client STA determine whether a data frame transmitted to the AP was delivered or not?
If the AP transmits any other frames, the STA can assume it received the transmitted frame.
If no collision was detected, the data frame was delivered.
Frames are always delivered on the WM, so the STA can assume delivery.
If a matching Ack frame is received, the data frame was delivered.
If a matching Ack frame is received, the data frame was delivered.
What metric or parameter is not likely to be used by a client STA when selecting a BSS to which it will connect?
Retry rate
RSSI
Supported data rates
Beacon frame signal strength
Retry rate
What original authentication method of the 802.11-1997 standard is still included in the standard and non-deprecated?
CCMP
Open System Authentication
Shared Key Authentication
WEP
Open System Authentication
When an 800-nanosecond delay is inserted between symbols, what is certainly in use?
Short guard interval
Long guard interval
DIFS
SIFS
Long guard interval
What is used to synchronize the receiver for reception of an 802.11 PPDU?
PLCP header
Preamble
FCS
MAC header
Preamble
You manage a WLAN with 200 802.11n APs and all APs are configured for 40 MHz channels in the 2.4 GHz and 5 GHz bands. The APs use band steering to encourage more clients to connect on the 5 GHz band. AirTime Fairness is also enabled and the low data rates of 1 and 2 Mbps are disabled. The 2.4 GHz clients are experiencing significant performance problems even though they connect to the various BSSs without problems. What should be changed in this configuration immediately to have the greatest impact on 2.4 GHz client performance?
Change the 2.4 GHz channels to use only 20 MHz channel widths
Turn off the 2.4 GHz radios on 75% of the APs
Enable the 1 and 2 Mbps data rates
Turn off AirTime Fairness
Change the 2.4 GHz channels to use only 20 MHz channel widths