CWNA-108 Practice Test 2 Flashcards by Gordon Racher

When an RF wave encounters obstacles smaller than the wavelength and reflective in nature, what is likely to occur?

Warping

Refraction

Scattering

Reflection

Scattering

How well did you know this?

Not at all

Perfectly

What is the term used when measuring return loss caused by mismatched impedance in RF cables and connectors?

Attenuation Factor

EIRP

VSWR

VSWR (Voltage Standing Wave Ratio)

How well did you know this?

Not at all

Perfectly

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)

How well did you know this?

Not at all

Perfectly

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)

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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.

How well did you know this?

Not at all

Perfectly

What term describes an RF transmission system up to but not including the antenna?

EIRP

Chipset

Intentional Radiator

Radio

Intentional Radiator

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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.

How well did you know this?

Not at all

Perfectly

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.

How well did you know this?

Not at all

Perfectly

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.

How well did you know this?

Not at all

Perfectly

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?

144

153

How well did you know this?

Not at all

Perfectly

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.

How well did you know this?

Not at all

Perfectly

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

S1G

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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)

How well did you know this?

Not at all

Perfectly

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)

How well did you know this?

Not at all

Perfectly

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 well did you know this?

Not at all

Perfectly

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.

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

What is used to synchronize the receiver for reception of an 802.11 PPDU?

PLCP header

Preamble

FCS

MAC header

Preamble

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

What new feature introduced with 802.11ac was designed to improve power management in the 5 GHz band? VHT TXOP Consistent use of A-MPDU 8 stream MIMO 256-QAM

VHT TXOP

When an 802.11 STA received a frame not intended for it, what field indicates the length of time required to complete the frame transaction after the current frame being received? Duration/ID Retry Length Type

Duration/ID

What kind of 802.11 device is most likely to have multiple LAN switch ports, a WAN/Internet port, and dual-band 802.11 radios? WLAN bridge Mesh AP Enterprise AP Home WLAN router

Home WLAN router

What Wi-Fi Alliance certification/standard can be used by hotspots to allow client devices to connect automatically if the hotspot supports a subscription service to which the client is subscribed? WMM WPA2 Voice-Enterprise Passpoint

Passpoint

A temporary mobile office is being deployed. In addition to the local WLAN, what will be required to provide Internet access at the site among the listed options? Wireless backhaul Ethernet switches and IP routers LDAP server RADIUS server

Wireless backhaul

When implementing PoE, what role is played by a wireless AP? PD PSE Power splitter Midspan injector

PD (powered device)

You have several 802.11n APs that require only 802.3af PoE power. What is the minimum power that is expected to be available for the PD in this scenario assuming proper cable lengths are used? 25.5 W 30 W 15.4 W 12.95 W

12.95 W

What high availability solution uses one controller as a backup for several other controllers in case a controller fails? N+1 RAID5 Striping Clustering

N+1

When centralized data forwarding is used in a controller-based architecture, what device creates the 802.3 Ethernet frames, removing all 802.11-specific information, and properly tags them with QoS markings to be forwarded onto the destination? AP IP router Client Controller

Controller

In an 802.11 2.4 GHz system, what 20 MHz channels are considered non-overlapping? 3 and 8 2 and 6 1 and 4 3 and 6

3 and 8

If the center frequency of channel 2 is 2417 MHz, what is the center frequency of channel 5? 2412 2420 2485 2432

2432 simply add 15 MHz

You must enable a feature on APs that allows for higher data rate clients to receive more time for frame reception from the APs than lower data rate clients. What is this feature? Band Steering RTS/CTS Load Balancing AirTime Fairness

AirTime Fairness

You are implementing an MDM solution. For what might this be used? VPN endpoint Automatic channel selection BYOD High availability for controllers

BYOD

The documentation from your WLAN vendor indicates that the time clocks on all devices must be synchronized. What service may be used on the network to perform this action? LDAP NTP (Network Time Protocol) DNS (Domain name system) RADIUS

NTP (Network Time Protocol)

What statement is true about the Ethernet cables used for AP connectivity? CAT6 Ethernet cables provide superior performance to CAT5 Ethernet cables. PoE can operate across CAT5e cables, but CAT3 cables are sufficient for providing 802.3at PoE power. If you use CAT6 cabling, you can install 250 meter cable runs instead of the 100 meter limit of CAT5e. The minimum required Ethernet cable type for 802.11ac APs is CAT3.

CAT6 Ethernet cables provide superior performance to CAT5 Ethernet cables.

What configuration option is sometimes thought to be a security solution for WLANs, but is easily circumvented by attackers? EAP-TLS SSID hiding CCMP WPA2

SSID hiding

What protocol should be used for Web-based administration interfaces in order to increase security? SNMPv3 HTTP HTTPS HTML

HTTPS

What encryption algorithm is used by WPA2-Enterprise in secure WLANs using no deprecated 802.11 solutions? 3DES AES DES RC4

AES (The Advanced Encryption Standard)

When using 802.1X/EAP authentication, what is the most common authentication server used in organizations? RADIUS Controller AD DS Domain Controller TACACS

RADIUS

What solution can detect and mitigate rogue devices discovered on the WLAN? Host-based IDS LDAP server RTLS server WIPS

WIPS (Wireless Intrusion Prevention System)

When using a protocol analyzer, what should you look at to see the duration value for a particular data frame in the capture? Traffic flows Traffic statistics Packet decode Expert views

Packet decode

What is the most common metric given for maximum unidirectional delay in VoIP communications? 300 ms 150 ms 10 ms 50 ms

150 ms

Which one of the following is a kind of 802.11-based interference caused by 802.11 devices? ZigBee ACI Bluetooth RFID

ACI (Adjacent Channel Interference)

What is an important consideration when determining the impact of a non-Wi-Fi interferer on the 802.11 channels nearby? Protocols used by the interferer Age of the interfering device Frequencies used by the interferer Coding rate used by the interferer

Frequencies used by the interferer

You have implemented a real-time video conferencing system on your WLAN. What two factors will be most important to the quality of communications in this system? Authentication and encryption Latency and jitter Latency and encryption Throughput and reliability

Throughput and reliability

What is the primary difference between throughput testing and load testing? Throughput testing is often a single machine test and load testing includes a simulated production load. Throughput testing is not supported on WLANs, but load testing is. Load testing is not supported on WLANs, but throughput testing is. Throughput testing provides no value while load testing does provide value.

Throughput testing is often a single machine test and load testing includes a simulated production load.

When using wireless design software for post-implementation validation, what is performed that is not performed in predictive modeling design scenarios? Drawing walls and other materials Capture of signals within the physical space Indicating AP locations Calibration or scaling of the floor plan

Capture of signals within the physical space

After performing corrective actions, according to the CWNP troubleshooting methodology, what action should be taken next? Define possible causes Discover the scale of the problem Document the results Verify the solution

Verify the solution

What is the first step in the CWNP troubleshooting methodology? Verify the solution Define possible causes Document the results Identify the problem

Identify the problem

You are troubleshooting a performance problem experienced by several STAs in an area approximately five square meters in size. You want to see if a non-Wi-Fi interferer is in the space. What tool should you use? WLAN scanner Spectrum analyzer Throughput tester WLAN protocol analyzer

Spectrum analyzer

What is an advantage of a centralized WLAN monitoring solution that is not available in most laptop-based protocol analyzers? Data aggregation from multiple real-time sources for automated reporting and analysis Expert views Frame capture and decoding Traffic statistics for the BSA

Data aggregation from multiple real-time sources for automated reporting and analysis

What will decrease in an environment when the noise floor increases? Signal strength SNR Transmit power Antenna gain

SNR (signal-to-noise ratio)

What is a common solution to hidden node problems in WLANs? Increasing the AP fragmentation threshold Reducing the client output power Enabling RTS/CTS Reducing the client antenna gain

Enabling RTS/CTS

You have determined that an AP is not getting sufficient PoE power because it will not power up. You have verified that the CAT6 cable is only 30 meters in length and is connected to a switch port with PoE enabled. What should you check next? Verify that the AP has the “use PoE" hardware switch set to "on" Verify that the power budget in the switch as sufficient remaining power for the AP Verify that the midspan injector is powered on Verify that the CAT6 cable is blue and not yellow

Verify that the power budget in the switch as sufficient remaining power for the AP

You are troubleshooting a problem with a USB adapter on a laptop. When you insert the adapter, after having installed the drivers, it is not detected by the operating system and no wireless networks are shown. The adapter has been tested on another machine where it works properly. What is a practical next action to take in this scenario? Install a third-party supplicant to use the adapter in the problem laptop Reinstall the operating system on the problem laptop Check the driver version in use on the working computer and ensure the same driver version is used on the problem laptop Delete the driver from the problem laptop and use the adapter without a driver

Check the driver version in use on the working computer and ensure the same driver version is used on the problem laptop

A customer complains of low throughput when connected to the WLAN. When you evaluate the AP signal strength that covers his work location, you see that it is at -62 dBm. Fewer than 40 clients associate with the same AP. When you ask other users if they have experienced throughput problems, those farther from the original customer indicate that they do not and those closer to the original customer indicate that they do. All clients are on the 5 GHz AP channel. What is the likely problem among those listed? Low signal strength The use of a CAT5e cable for the AP connection Non-Wi-Fi interference Improper use of band steering

Non-Wi-Fi interference

CWNA-108 Practice Test 2 Flashcards

(60 cards)