[Apr-2024] Pass CWNP CWNA-108 Tests Engine pdf - All Free Dumps
CWNP Certified Wireless Network Administrator Exam Practice Tests 2024 | Pass CWNA-108 with confidence!
NEW QUESTION # 56
What is a common feature of an 802.11 WLAN client utility? (Choose 2)
- A. AP Signal strength meter
- B. VLAN configuration
- C. Spectrum analyzer utility
- D. Real-time retry monitor
- E. Link statistics display
Answer: A,E
NEW QUESTION # 57
During a post-implementation survey, you have detected a non-802.11 wireless device transmitting in the area used by handheld 802.11g scanners. What is the most important factor in determining the impact of this non-802.11 device?
- A. Receive sensitivity
- B. Channel occupied
- C. Protocols utilized
- D. Airtime utilization
Answer: D
Explanation:
Airtime Utilization is a per-channel statistic that defines what percentage of the channel is currently being used, and what percentage is therefore free. Airtime usage can come from: Data traffic to and from client devices. Interference from WiFi and non-WiFi sources. Management overhead from APs and client devices. https://wyebot.com/2019/06/06/understanding-airtime-utilization/
NEW QUESTION # 58
Which of the following frequency ranges are specified for use by IEEE 802.11 radios? (Choose all that apply.)
- A. 2.4000 - 2.4835 GHz
- B. 5.470 - 5.725 GHz
- C. 5.725 - 5.875 GHz
- D. 902 - 928 MHz
- E. 5.15 - 5.25 GHz
Answer: A,B,C,E
NEW QUESTION # 59
You are troubleshooting a controller-based AP that is unable to locate the controller. DHCP is not use and the controller is located at 10.10.10.81/24 while the AP is on the 10.10.16.0/24 network.
What should be inspected to verify proper configuration?
- A. BOOTH
- B. DNS
- C. NTP
- D. AP hosts file
Answer: B
NEW QUESTION # 60
Which IEEE 802.11 physical layer (PHY) specifications include support for and compatibility with both ERP and HR/DSSS?
- A. HT (802.11n)
- B. DSSS (802.11-Prime)
- C. VHT (802.11ac)
- D. OFDM (802.11a)
Answer: A
NEW QUESTION # 61
You are attempting to locate the cause of a performance problem in two WLAN cells in a mostly overlapping coverage area. You note that one AP is on channel 1 and the other is on channel 2.
When you document yoy findings, what term do you use to describe the problem in this configuration?
- A. ACI
- B. Bluetooth interference
- C. Non-Wi-Fi interference
- D. CCI
Answer: A
Explanation:
Adjacent channel interference is more serious and occurs when 2 or more AP's are on overlapping channels, for example channel 1 + 4 on the 2.4Ghz band. ACI creates overlap in the frequency space causing corrupted data and layer 2 re-transmissions.
NEW QUESTION # 62
What authentication method is referenced in the 802.11-2016 and 802.11-2020 specifications and is recommended for robust WI-AN client security?
- A. 802.1X/EAP
- B. SSL
- C. WEP
- D. IPSec
Answer: A
Explanation:
Explanation
The authentication method that is referenced in the 802.11-2016 and 802.11-2020 specifications and is recommended for robust WLAN client security is 802.1X/EAP. 802.1X/EAP stands for IEEE 802.1X Port-Based Network Access Control with Extensible Authentication Protocol and is a framework that provides strong authentication and dynamic encryption key generation for WLAN clients. 802.1X/EAP involves three parties: the supplicant (the client), the authenticator (the AP or the controller), and the authentication server (usually a RADIUS server). The supplicant sends its credentials (such as username and password, certificate, or token) to the authenticator, which forwards them to the authentication server. The authentication server verifies the credentials and sends a response to the authenticator, which grants or denies access to the supplicant. The authentication server also generates a master key that is used to derive encryption keys for the data frames between the supplicant and the authenticator. 802.1X/EAP supports various EAP methods that offer different levels of security and flexibility, such as EAP-TLS, EAP-PEAP, EAP-TTLS, EAP-FAST, and EAP-SIM. SSL, IPSec, and WEP are not authentication methods, but rather encryption or security protocols that are not specific to WLANs or referenced in the 802.11 specifications. References: [CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-107], page 299; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-106], page 289.
NEW QUESTION # 63
What is a channel mode specified by the 802.11n (High Throughput) PHY?
- A. 80 MHz
- B. 20/40 MHz
- C. Frequency Hopping
- D. 22 MHz
Answer: B
NEW QUESTION # 64
When using a spectrum to look for non Wi-Fi interference sources, you notice significant interference across the entire 2.4 GHz band (not on a few select frequencies) within the desktop area of a users workspace, but the interference disappears quickly after just 2 meters. What is the most likely cause of this interference?
- A. Unintentional radiation from the PC power supply
- B. USB 3 devices in the user's work area
- C. Excess RF energy from a nearby AP
- D. Bluetooth devices in the user's work area
Answer: B
Explanation:
Explanation
USB 3 devices in the user's work area are the most likely cause of this interference when using a spectrum analyzer to look for non-Wi-Fi interference sources. A spectrum analyzer is a tool that measures and visualizes the radio frequency activity and interference in the wireless environment. A spectrum analyzer can show the spectrum usage and energy levels on each frequency band or channel and help identify and locate the sources of interference. Interference is any unwanted signal that disrupts or degrades the intended signal on a wireless channel. Interference can be caused by various sources, such as other Wi-Fi devices, non-Wi-Fi devices, or natural phenomena. Interference can affect WLAN performance and quality by causing signal loss, noise, distortion, or errors. USB 3 devices are non-Wi-Fi devices that use USB 3.0 technology to transfer data at high speeds between computers and peripherals, such as hard drives, flash drives, cameras, or printers. USB 3 devices can generate electromagnetic radiation that interferes with Wi-Fi signals in the 2.4 GHz band, especially when they are close to Wi-Fi devices or antennas. USB 3 devices can cause significant interference across the entire 2.4 GHz band (not on a few select frequencies) within the desktop area of a user's workspace, but the interference disappears quickly after just 2 meters. This is because USB 3 devices emit broadband interference that affects all channels in the 2.4 GHz band with a high intensity near the source but a low intensity at a distance due to attenuation. The other options are not likely to cause this interference pattern when using a spectrum analyzer to look for non-Wi-Fi interference sources. Bluetooth devices in the user's work area are non-Wi-Fi devices that use Bluetooth technology to communicate wirelessly between computers and peripherals, such as keyboards, mice, headphones, or speakers. Bluetooth devices can cause interference with Wi-Fi signals in the 2.4 GHz band, but they use frequency hopping spread spectrum (FHSS) technique that changes frequencies rapidly and randomly within a range of 79 channels. Therefore, Bluetooth devices do not cause significant interference across the entire 2.4 GHz band (not on a few select frequencies), but rather intermittent interference on some channels at different times. Excess RF energy from a nearby AP is not a non-Wi-Fi interference source but rather a Wi-Fi interference source that occurs when an AP transmits more power than necessary for its coverage area. Excess RF energy from a nearby AP can cause co-channel interference (CCI) with other APs or client devices that use the same channel within range of each other. CCI reduces performance and capacity because it causes contention and collisions on the wireless medium,
NEW QUESTION # 65
As an RF wave propagates through space, the wave front experiences natural expansion that reduces its signal strength in an area. What describes the rate at which this expansion happens?
- A. MU-MIMO
- B. Fresnel zone thinning
- C. Ohm's law
- D. Inverse square law
Answer: D
Explanation:
Explanation
The inverse square law states that the signal strength of an RF wave is inversely proportional to the square of the distance from the source. This means that as the distance from the transmitter increases, the signal strength decreases rapidly.
References: Wireless Network Administrator Official Study Guide, Chapter 3, page 64.
NEW QUESTION # 66
Your consulting firm has recently been hired to complete a site survey for a company. Your engineers use predictive modeling software for surveying, but the company insists on a pre- deployment site visit.
What task should be performed as part of the pre-deployment visit to prepare for a predictive survey?
- A. Install at least one AP on each side of the exterior walls to test for co-channel interference through these walls.
- B. Test several antenna types connected to the intended APs for use in the eventual deployment.
- C. Evaluatethe building materials at ABC's facility and confirm that the floor plan documents are consistent with the actual building.
- D. Collect information about the company's security requirements and the current configuration of their RADIUS and user database servers.
Answer: C
NEW QUESTION # 67
You have received a report of poor wireless connections on the third floor of a building under your administration. Three individuals have reported the problem. Apparently, the connections are reporting a strong signal, but the users cannot access the Internet. With the problem identified, what is the next logical step in the troubleshooting process?
- A. Verify the solution
- B. Discover the scale of the problem
- C. Perform corrective actions
- D. Create a plan of action or escalate the problem
Answer: C
NEW QUESTION # 68
You are using a site survey tool for post-implementation validation. You have installed the appropriate adapter driver and imported a floor plan. Now, you want to take the next step in proper tool use. What must you do before gathering survey data after the floor plan is imported?
- A. Calibrate the floor plan
- B. Nothing, you can simply start capturing signal readings
- C. Install iPerf
- D. Install WinPCAP
Answer: A
NEW QUESTION # 69
When a client station sends a broadcast probe request frame with a wildcard SSID, how do APs respond?
- A. Each AP checks with the DHCP server to see if it can respond and then acts accordingly.
- B. Each AP responds in turn after preparing a probe response and winning contention.
- C. After waiting a SIFS, all APs reply at the same time with a probe response.
- D. For each probe request frame, only one AP may reply with a probe response.
Answer: B
Explanation:
Explanation
A probe request frame is a management frame that is sent by a client station to discover available wireless networks in its vicinity. A probe request can be either unicast or broadcast, depending on whether it specifies a particular SSID (Service Set Identifier) or a wildcard SSID. A broadcast probe request with a wildcard SSID is used to solicit responses from all APs within range, regardless of their SSIDs. Each AP that receives a broadcast probe request prepares a probe response frame that contains information about its network, such as SSID, supported rates, channel, security, etc. However, before sending the probe response, each AP must contend for the medium using the CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) protocol, which is the basic access method for 802.11 WLANs. This means that each AP must sense the channel for a DIFS (Distributed Interframe Space) interval, which is longer than a SIFS interval, and then generate a random backoff time before transmitting. This reduces the probability of collisions and ensures fair access to the medium among multiple APs. Therefore, each AP responds in turn after preparing a probe response and winning contention . References: [CWNA-109 Study Guide], Chapter 5: IEEE 802.11 Medium Access, page 215; [CWNA-108 Study Guide], Chapter 5: IEEE 802.11 Medium Access, page 209;
[CWNA-109 Study Guide], Chapter 6: Wireless LAN Devices and Topologies, page 255.
NEW QUESTION # 70
What statement about 802.11 WLAN bridges is true?
- A. WLAN bridges only work in the 2.4 GHz frequency band and they support only SISO communications
- B. WLAN bridges must use a channel with acceptable SNR at both transceivers to maintain the desired data rate bi-directionally
- C. WLAN bridges may support MIMO communications, but only if used in the 5 GHz frequency band
- D. WLAN bridges must be implemented such that no interference occurs on the channel anywhere between the two endpoints used to establish the bridge
Answer: B
Explanation:
Explanation
WLAN bridges must use a channel with acceptable SNR at both transceivers to maintain the desired data rate bi-directionally. A WLAN bridge is a device that connects two or more networks using the 802.11 protocol. A WLAN bridge must have a clear and strong signal between the two endpoints to ensure reliable and fast data transmission. The signal-to-noise ratio (SNR) is a measure of the quality of the signal, which depends on the distance, interference, obstacles, and antenna gain between the transceivers. A higher SNR means a better signal quality and a higher data rate. A lower SNR means a worse signal quality and a lower data rate. Therefore, a WLAN bridge must use a channel with acceptable SNR at both transceivers to maintain the desired data rate bi-directionally1.
NEW QUESTION # 71
You were previously onsite at XYZ's facility to conduct a pre-deployment RF site survey. The WLAN has been deployed according to your recommendations and you are onsite again to perform a post-deployment validation survey.
When performing this type of post-deployment RF site survey voice over Wi-Fi, what is an action that must be performed?
- A. Protocol analysis to discover channel use on neighboring APs.
- B. Spectrum analysis to locate and identify RF interference sources.
- C. Application analysis with an active phone call on an VoWiFi handset.
- D. Frequency-band hopping analysis to detect improper RF channel implementations.
Answer: C
NEW QUESTION # 72
A WLAN is implemented using wireless controllers. The APs must locate the controllers when powered on and connected to the network. Which one of the following methods is commonly used to locate the controllers by the APs?
- A. NTP
- B. DHCP
- C. SNMP
- D. GRE
Answer: B
Explanation:
Explanation
DHCP (Dynamic Host Configuration Protocol) is a commonly used method to locate the controllers by the APs in a WLAN that is implemented using wireless controllers. DHCP is a protocol that allows a device to obtain an IP address and other network configuration parameters from a server. In a wireless controller scenario, the APs can use DHCP to request an IP address from a DHCP server, which can also provide the IP address or hostname of the wireless controller as an option in the DHCP response. This way, the APs can discover the wireless controller and establish a connection with it. Alternatively, the APs can also use other methods to locate the wireless controller, such as DNS (Domain Name System), broadcast or multicast discovery, or manual configuration. References: 1, Chapter 8, page 309; 2, Section 5.2
NEW QUESTION # 73
You have received a report of poor wireless connections on the third floor of a building under your administration. Three individuals have reported the problem. Apparently, the connections are reporting a strong signal, but the users cannot access the Internet. With the problem identified, what is the next logical step in the troubleshooting process?
- A. Verify the solution
- B. Perform corrective actions
- C. Discover the scale of the problem
- D. Create a plan of action or escalate the problem
Answer: C
NEW QUESTION # 74
You are attempting to explain RF shadow and how it can cause lack of coverage. What common building item frequently causes RF shadow and must be accounted for in coverage plans?
- A. Wooden doors
- B. Carpeted floors
- C. Cubicle partitions
- D. Elevators
Answer: C
NEW QUESTION # 75
An RF signal sometimes bends as it passes through some material other than free space. What is the term that describes this behavior?
- A. Scattering
- B. Reflection
- C. Warping
- D. Refraction
Answer: D
Explanation:
Explanation
Refraction is the bending of an RF signal as it passes through a medium with a different density than free space. This can cause the signal to change its direction and speed, which can affect the accuracy and reliability of wireless communication. Refraction is influenced by factors such as temperature, humidity, and atmospheric pressure12. References: CWNA-109 Study Guide, Chapter 2: Radio Frequency Fundamentals, page 72; CWNA-108 Study Guide, Chapter 2: Radio Frequency Fundamentals, page 67.
NEW QUESTION # 76
AP-1 is a 3x3:2 AP. STA-3 is a 3x3:3 client. What is the maximum number of spatial streams that can be used for a downlink HT-OFDM transmission from AP-1 to STA-3?
- A. Three spatial streams, because the definition of the client indicates that it is capable of only three spatial streams.
- B. Three spatial streams, because the definition of the AP indicates that it is capable of only three spatial streams.
- C. One spatial stream, because the definition of the AP indicates that it is capable of only one spatial stream.
- D. Two spatial streams, because the definition of the AP indicates that it is capable of only two spatial streams.
Answer: D
NEW QUESTION # 77
When compared with legacy Power Save mode, how does VHT TXOP power save improve battery life for devices on a WLAN?
- A. Legacy Power Save mode was removed in the 802.11ac amendment.
- B. VHT TXOP power save allows the WLAN transceiver to disable more components when in a low power state.
- C. VHT TXOP power save allows stations to enter sleep mode and legacy Power Save does not.
- D. VHT TXOP power save uses the partial AID in the preamble to allow clients to identify frames targeted for them.
Answer: D
Explanation:
Explanation
VHT TXOP power save uses the partial AID in the preamble to allow clients to identify frames targeted for them. VHT TXOP power save is a feature introduced in the 802.11ac amendment that improves battery life for devices on a WLAN by allowing them to enter sleep mode more frequently and for longer periods of time. It works by using a new field called partial AID in the preamble of VHT frames that indicates which stations are addressed by the frame. This allows stations to quickly determine if they need to wake up and receive the frame or stay in sleep mode and save power. This reduces the overhead and latency of legacy Power Save mode, which requires stations to wake up periodically and listen to Beacon frames or other control frames to check if there are any buffered frames for them at the AP. References: , Chapter 3, page 117; , Section 3.2
NEW QUESTION # 78
Which directional antenna types are commonly used by indoor Wi-Fi devices in a MIMO multiple spatial stream implementation?
- A. Dipole and yagi
- B. Grid and sector
- C. Patch and panel
- D. Dish and grid
Answer: C
Explanation:
Explanation
Patch and panel antennas are directional antenna types that are commonly used by indoor Wi-Fi devices in a MIMO multiple spatial stream implementation. These antennas have a flat rectangular shape and can be mounted on walls or ceilings to provide coverage in a specific direction. They have a moderate gain and a relatively wide beamwidth, making them suitable for multipath environments where signals can reflect off different surfaces and create multiple spatial streams. Patch and panel antennas can also support polarization diversity, which means they can transmit and receive both horizontally and vertically polarized waves, increasing the MIMO performance. References: 1, Chapter 2, page 72; 2, Section 2.4
NEW QUESTION # 79
What can an impedance mismatch in the RF cables and connectors cause?
- A. Increased amplitude of the RF signal
- B. Increased range of the RF signal
- C. Excessive VSWR
- D. Fewer MCS values in the MCS table
Answer: C
Explanation:
Explanation
VSWR stands for Voltage Standing Wave Ratio, which is a measure of how well the impedance of the RF cable and connectors matches the impedance of the transmitter and the antenna. Impedance is the opposition to the flow of alternating current in an RF circuit, and it depends on the frequency, resistance, capacitance, and inductance of the components. A perfect impedance match would have a VSWR of 1:1, meaning that all the power is transferred from the transmitter to the antenna, and none is reflected back. However, in reality, there is always some degree of mismatch, which causes some power to be reflected back to the transmitter, creating standing waves along the cable. This reduces the efficiency and performance of the wireless system, and can also damage the transmitter. Excessive VSWR can be caused by using poor quality or damaged cables and connectors, or by using components that have different impedance ratings123. References: CWNA-109 Study Guide, Chapter 2: Radio Frequency Fundamentals, page 90; CWNA-108 Study Guide, Chapter 2: Radio Frequency Fundamentals, page 86; CWNP website, CWNA Certification.
NEW QUESTION # 80
What phrase defines Equivalent Isotropically Radiated Power (EIRP)?
- A. The power output from the radio into the RF cable
- B. Power supplied from the transmission line to the antenna input
- C. The highest RF signal strength that is transmitted from a given antenna
- D. The power output from the radio after cable losses
Answer: C
NEW QUESTION # 81
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