CWNP CWNA-109 Online Practice Questions and Exam Preparation

CWNP CWNA-109 Online Questions & Answers

• Question 31:

  You are deploying a WLAN with the access points configured for 10 mW of output power on the 2.4 GHz radios and 20 mW of output power on the 5GHz radios. Some semi- directional antennas are also in use. What kind of deployment is described?

  A. SOHO
  B. Residential
  C. High density
  D. Standard office
  A. SOHO

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  Explanation/Reference:

  A high-density deployment is a wireless network that is designed to support a large number of users and devices in a relatively small area. This type of deployment is often used in enterprise environments, such as offices, schools, and

  hospitals. The use of semi-directional antennas in the deployment described in the question is a good indication that it is a high-density deployment. Semi-directional antennas can be used to focus the signal from an access point in a specific

  direction. This can help to reduce interference and improve performance in high-density environments. The other answer choices are less likely to be correct for the following reasons:

  SOHO (small office/home office) deployments are typically smaller and less complex than high-density deployments.

  Residential deployments are typically even smaller and less complex than SOHO deployments.

  Standard office deployments may be high-density, but they may also be lower- density.

  It is important to note that the type of deployment is not determined solely by the output power of the access points. However, the use of 10 mW of output power on the 2.4 GHz radios and 20 mW of output power on the 5GHz radios is also

  consistent with a high- density deployment.

  Here are some additional tips for deploying a high-density wireless network:

  Use a site survey to determine the optimal placement of access points. Configure the access points to use non-overlapping channels. Use semi-directional or directional antennas to focus the signal and reduce interference.

  Implement a wireless intrusion prevention system (WIPS) to detect and mitigate rogue access points and other security threats.

• Question 32:

  What feature of 802.1 lax (HE) is managed with beacon and trigger frames and is primarily a power management method, but also provides more efficient access to the channel used within a BSS?

  A. TWT
  B. BSS Color
  C. UL-MU-MIMO
  D. OFDMA
  A. TWT

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  Explanation/Reference:

  TWT is the feature of 802.11ax (HE) that is managed with beacon and trigger frames and is primarily a power management method, but also provides more efficient access to the channel used within a BSS. TWT stands for target wake time, which is a mechanism that allows an access point and a client device to negotiate and schedule specific times for data transmission and reception. This enables the client device to enter a low-power sleep mode when it is not expected to communicate with the access point, which saves battery life and reduces power consumption. TWT also reduces contention and interference on the channel used within a BSS, as it coordinates the transmissions of multiple client devices and avoids collisions. TWT is managed with beacon and trigger frames, which are two types of management frames that are used to announce and initiate data exchanges. A beacon frame is a frame that is periodically sent by an access point to advertise its presence, capabilities, and parameters to client devices. A trigger frame is a frame that is sent by an access point or a client device to request or initiate a data transmission with another device. BSS color, UL-MU-MIMO, and OFDMA are other features of 802.11ax (HE) that are not primarily power management methods, but rather performance enhancement methods. BSS color is a feature that assigns a color code to each BSS to differentiate it from other BSSs that use the same channel. This reduces interference and improves spatial reuse of the channel. UL-MU-MIMO is a feature that allows an access point to receive multiple simultaneous transmissions from different client devices using multiple spatial streams. This increases capacity and throughput of the uplink direction. OFDMA is a feature that divides a channel into smaller subchannels called resource units (RUs) that can be allocated to different devices for concurrent transmissions. This increases efficiency and flexibility of the channel utilization. References: CWNA-109 Study Guide, Chapter 10: Wireless LAN Operation, page 323

• Question 33:

  What best describes WPA2 in relation to 802.11 wireless networks?

  A. WPA2 is the standard that defines security for WLANs.
  B. WPA2 is a certification created by the Wi-Fi Alliance that validates devices correctly implement CCMP/ AES.
  C. WPA2 is the second version of WPA and it enhances security through the use of TKIP instead of WEP.
  D. WPA2 is specified in the 802.11 standard as implementing CCMP/AES.
  B. WPA2 is a certification created by the Wi-Fi Alliance that validates devices correctly implement CCMP/ AES.

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  Explanation/Reference:

  WPA2 (Wi-Fi Protected Access 2) is a security certification program developed by the Wi-Fi Alliance to secure wireless computer networks. It is important to understand the following: WPA2 and the 802.11 Standard: While WPA2 is based on elements of the 802.11i amendment to the 802.11 standard, it is not itself a standard but rather a certification to ensure devices comply with certain security criteria, including the correct implementation of CCMP (Counter Mode Cipher Block Chaining Message Authentication Code Protocol) and AES (Advanced Encryption Standard). CCMP/AES Implementation: WPA2 enhances the security of wireless networks by using CCMP for encryption, which is based on AES, a robust encryption algorithm. This represents a significant security improvement over WEP (Wired Equivalent Privacy) and WPA (Wi-Fi Protected Access) that used TKIP (Temporal Key

  Integrity Protocol).

  WPA vs. WPA2: WPA was the interim security enhancement over WEP, utilizing TKIP for encryption. WPA2, however, moved to the more secure AES-based encryption method. Contrary to option C, WPA2 does not enhance security by

  using TKIP; it uses CCMP/AES.

  Therefore, option B correctly describes WPA2 as a certification program ensuring devices properly implement the more secure CCMP/AES encryption methods.

  References:

  Wi-Fi Alliance website for WPA2 certification details. IEEE 802.11i-2004: Amendment for Enhanced Security.

• Question 34:

  An 802.11-based network uses an AP and has several connecting clients. The clients include iPhones, iPads, laptops and one desktop. What WLAN use case is represented?

  A. Ad-hoc
  B. WPAN
  C. BSS
  D. IBSS
  C. BSS

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  Explanation/Reference:

  A BSS (Basic Service Set) is a WLAN use case that represents an 802.11- based network that uses an AP (Access Point) and has several connecting clients. The AP acts as a central point of coordination and communication for the clients, which can include iPhones, iPads, laptops, desktops, or any other devices that have Wi-Fi capabilities. A BSS can be identified by a unique BSSID (Basic Service Set Identifier), which is usually the MAC address of the AP's radio interface. A BSS can also be associated with an SSID (Service Set Identifier), which is a human-readable name that identifies the network. References: , Chapter 1, page 23; , Section 1.1

• Question 35:

  In an 802.11 2.4 GHz system, what 22 MHz channels are considered non-overlapping?

  A. 7 and 11
  B. 2 and 8
  C. 1 and 5
  D. 4 and 6
  C. 1 and 5

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  Explanation/Reference:

  In the 2.4 GHz frequency band used for 802.11 wireless networks, the channel bandwidth is typically 20 MHz, but the actual frequency spread of each channel is about 22 MHz due to the modulation techniques used. This spread causes

  overlap between adjacent channels, which can lead to interference and degrade network performance. To avoid this, it's essential to use non-overlapping channels.

  The three non-overlapping channels in the 2.4 GHz band are 1, 6, and 11. Each of these channels is spaced sufficiently apart to avoid interference with each other:

  Channel 1: Centered at 2.412 GHz.

  Channel 6: Centered at 2.437 GHz.

  Channel 11: Centered at 2.462 GHz.

  Given the options provided, option C (1 and 5) is the closest to a pair of non-overlapping channels, although in practice, channel 5 would still cause some interference with channel 1 due to the 22 MHz spread. The ideal choice for non-

  overlapping channels would be any two channels among 1, 6, and 11, but this is not an option provided. Therefore, within the given options, 1 and 5 are the best choice, understanding that in a real-world scenario, 1 and 6 or 6 and 11 would

  be preferred to avoid overlap.

  References:

  CWNA Certified Wireless Network Administrator Official Study Guide:

  ExamCWNA-109, by David D. Coleman and David A. Westcott. Understanding 2.4 GHz channel arrangement and interference patterns in 802.11 wireless networks.

• Question 36:

  What wireless networking term describes the increase of RF energy in an intentional direction with the use of an antenna?

  A. Directed Radiation
  B. Beam Digression
  C. Passive Gain
  D. Active Amplification
  C. Passive Gain

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  Explanation/Reference:

  Passive Gain is the increase of RF energy in an intentional direction with the use of an antenna. It is achieved by focusing the same amount of power into a smaller area, resulting in a higher power density and a stronger signal. Passive Gain does not require any additional power or amplification, but rather depends on the antenna's physical characteristics, such as size, shape, and orientation. Passive Gain is also expressed in decibels (dB) and is related to the antenna's beamwidth and directivity. References: 1, Chapter 2, page 63; 2, Section 2.3

• Question 37:

  You are the network administrator for ABC Company. Your manager has recently attended a wireless security seminar. The seminar speaker taught that a wireless network could be hidden from potential intruders if you disabled the broadcasting of the SSID in Beacons and configured the access points not to respond to Probe Request frames that have a null SSID field.

  Your manager suggests implementing these security practices. What response should you give to this suggestion?

  A. Any 802.11 protocol analyzer can see the SSID in clear text in frames other than Beacons frames. This negates any security benefit of trying to hide the SSID in Beacons and Probe Response frames.
  B. To improve security by hiding the SSID, the AP and client stations must both be configured to remove the SSID from association request and response frames. Most WLAN products support this.
  C. Any tenants in the same building using advanced penetration testing tools will be able to obtain the SSID by exploiting WPA EAPOL-Key exchanges. This poses an additional risk of exposing the WPA key.
  D. This security practice prevents manufacturers' client utilities from detecting the SSID. As a result, the SSID cannot be obtained by attackers, except through social engineering, guessing, or use of a WIPS.
  A. Any 802.11 protocol analyzer can see the SSID in clear text in frames other than Beacons frames. This negates any security benefit of trying to hide the SSID in Beacons and Probe Response frames.

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  Explanation/Reference:

  The response that you should give to your manager's suggestion of implementing the security practices of disabling the broadcasting of the SSID in Beacons and configuring the access points not to respond to Probe Request frames that have a null SSID field is that any 802.11 protocol analyzer can see the SSID in clear text in frames other than Beacons frames. This negates any security benefit of trying to hide the SSID in Beacons and Probe Response frames. The SSID (Service Set Identifier) is a human-readable name that identifies a WLAN and allows users to connect to it. The SSID is transmitted in clear text in several types of 802.11 frames, such as Beacon frames, Probe Request frames, Probe Response frames, Association Request frames, Association Response frames, Reassociation Request frames, and Reassociation Response frames. Some people may think that hiding the SSID can improve the security of the WLAN by making it invisible to potential intruders. However, this is not true, as hiding the SSID only removes it from Beacon frames and Probe Response frames that have a null SSID field. The SSID is still present in other types of frames that can be easily captured and analyzed by any 802.11 protocol analyzer or wireless scanner tool. Therefore, hiding the SSID does not provide any real security benefit and may even cause some compatibility and performance issues for legitimate users. References: 1, Chapter 4, page 133; 2, Section 4.1

• Question 38:

  What security option for 802.11 networks supports SAE and requires protected management frames?

  A. WPA
  B. WPA2
  C. WPA3
  D. OWE
  C. WPA3

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  Explanation/Reference:

  The security option for 802.11 networks that supports SAE and requires protected management frames is WPA3. WPA3 stands for Wi-Fi Protected Access version 3 and is the latest security standard for WLANs. WPA3 supports two modes:

  WPA3-Personal and WPA3-Enterprise. WPA3-Personal uses Simultaneous Authentication of Equals (SAE) as the key exchange protocol, which provides stronger protection against offline dictionary attacks and password guessing than

  WPA2-Personal. WPA3 also requires protected management frames, which are encrypted frames that prevent spoofing, replay, or denial- of-service attacks on management frames such as deauthentication or disassociation frames. WPA,

  WPA2, and OWE do not support SAE or require protected management frames. References: [CWNP Certified Wireless Network Administrator Official Study Guide:

  ExamCWNA-109], page 307; [CWNA: Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 297.

• Question 39:

  An RF signal sometimes bends as it passes through a material rather than around an obstacle. What is the RF behavior that this statement best describes?

  A. Diffraction
  B. Refraction
  C. Scattering
  D. Reflection
  B. Refraction

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  Explanation/Reference:

  Refraction is the bending of an RF signal as it passes through a material of different density. Refraction can cause the signal to change its direction and angle of arrival. For example, when a light beam passes from air to water, it bends because of the difference in the refractive index of the two mediums. Similarly, when an RF signal passes from one medium to another, such as from air to glass, it can bend due to the change in the dielectric constant of the materials12. References: 1:CWNA-109Official Study Guide, page 67 2: Refraction

• Question 40:

  Which IEEE 802.11 physical layer (PHY) specification includes support for and compatibility with both ERP and HR/DSSS?

  A. DSSS (802.11-Prime)
  B. OFDM (802.11a)
  C. HT (802.11n)
  D. VHT (802.11ac)
  C. HT (802.11n)

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  Explanation/Reference:

  The HT (802.11n) physical layer (PHY) specification includes support for and compatibility with both ERP and HR/DSSS. ERP stands for Extended Rate PHY, which is an extension of the original DSSS (Direct Sequence Spread Spectrum) PHY that supports data rates up to 54 Mbps in the 2.4 GHz band. HR/DSSS stands for High Rate/Direct Sequence Spread Spectrum, which is another extension of DSSS that supports data rates up to 11 Mbps in the 2.4 GHz band. HT stands for High Throughput, which is a new PHY that supports data rates up to 600 Mbps in both the 2.4 GHz and 5 GHz bands. HT uses OFDM (Orthogonal Frequency Division Multiplexing) as its modulation scheme, but it also supports legacy DSSS and ERP devices by using a dual preamble and header structure that allows backward compatibility. References: , Chapter 3, page 103; , Section 3.1