CWNP CWNA-109 Online Practice Questions and Exam Preparation

CWNP CWNA-109 Online Questions & Answers

• Question 81:

  A client STA must choose the best AP for connectivity. As part of the evaluation, it must verify compatible data rates. What can the client STA use to verify that an AP supports the same data rates that it supports?

  A. Beacon frames transmitted by the AP
  B. Data frames sent between the AP and current clients STAs
  C. Authentication frames transmitted by the other client STAs
  D. Probe request frames transmitted by other client STAs
  A. Beacon frames transmitted by the AP

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  Explanation/Reference:

  The client STA can use Beacon frames transmitted by the AP to verify that an AP supports the same data rates that it supports. Beacon frames are management frames that are periodically broadcasted by the APs to announce their presence, capabilities, and parameters. Oneof the information elements contained in the Beacon frames is the Supported Rates or Extended Supported Rates, which lists the data rates that the AP can use for communication. The client STA can compare its own data rates with those advertised by the AP to determine if they are compatible. Data frames, authentication frames, and probe request frames do not contain information about data rates. References: [CWNP Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 133; [CWNA: Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 123.

• Question 82:

  You are troubleshooting a client problem with a 2.4 GHz WLAN connection. The client is experiencing surprisingly low data rates during the work day. You analyze the workspace outside of business hours and detect a strong signal with a typical noise floor at the client location. During working hours, the user works with a laptop in the area and uses an external USB hard drive for continuous data access. The user also states that the laptop works as expected on her home network. The user working approximately 8 feet away from this client experiences no problems.

  Based on this information, what is the likely cause of the problem?

  A. The AP is overloaded during the work day
  B. The drivers in the laptop are corrupt
  C. The laptop has a failing wireless adapter
  D. The external hard drive is USB 3.0 and is causing a significant increase in the noise floor when in use
  D. The external hard drive is USB 3.0 and is causing a significant increase in the noise floor when in use

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  Explanation/Reference:

  The likely cause of the problem is that the external hard drive is USB 3.0 and is causing a significant increase in the noise floor when in use. USB 3.0 devices are known to generate radio frequency interference (RFI) in the 2.4 GHz band due to their high data transfer rates and harmonics. This RFI can increase the noise floor and degrade the signal- to-noise ratio (SNR) of WLAN devices operating in the same band. This can result in lower data rates, reduced throughput, increased retransmissions, and poor performance. The problem may not occur outside of business hours or on the user's home network because of different usage patterns or environmental factors. References: [CWNP Certified Wireless Network Administrator Official StudyGuide: ExamCWNA-109], page 527; [CWNA: Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 497.

• Question 83:

  ABC Company is planning a point-to-multipoint outdoor bridge deployment with standalone (autonomous) 802.11 bridge units. 802.1X/EAP will be used for bridge authentication. A Linux-based RADIUS server will be used for authentication. What device in the bridge implementation acts as the 802.1X Authenticator?

  A. The Ethernet switch
  B. The RADIUS server
  C. All non-root bridges
  D. The root bridge
  D. The root bridge

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  Explanation/Reference:

  The device in the bridge implementation that acts as the 802.1X Authenticator is the root bridge. The root bridge is the bridge that connects to the wired network and acts as the central point for all other bridges in the point-to-multipoint

  topology. The root bridge authenticates the non-root bridges using 802.1X/EAP and forwards their authentication requests to the RADIUS server. The non-root bridges act as the 802.1X Supplicants and use EAP methods such as EAP-TLS or

  EAP-PEAP to authenticate with the root bridge. References: [CWNP Certified Wireless Network Administrator Official Study Guide:

  ExamCWNA-109], page 459; [Cisco Aironet Wireless Bridges FAQ], question 29.

• Question 84:

  In addition to coverage analysis results, what should be included in a post-deployment site survey report to ensure WLAN users experience acceptable performance?

  A. WAN interface analysis results
  B. Capacity analysis results
  C. Application Layer protocol availability analysis results
  D. Layer 4 protocol availability analysis results
  B. Capacity analysis results

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  Explanation/Reference:

  In addition to coverage analysis results, what should be included in a post- deployment site survey report to ensure WLAN users experience acceptable performance is Capacity analysis results. Capacity analysis is a method of testing the ability of the WLAN to support the expected number and type of users, devices, and applications. Capacity analysis can help to determine the optimal number and placement of access points, the appropriate channel and power settings, the required QoS policies, and the expected throughput and latency levels. Capacity analysis results can help to verify that the WLAN meets the performance requirements and service level agreements (SLAs) of the organization. References: [CWNP Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 548; [CWNA: Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 518.

• Question 85:

  Which IEEE 802.11 physical layer (PHY) specification includes support for operation in the 2.4 GHz, 5 GHz, and 6 GHz bands?

  A. VHT (802.11ac).
  B. HT(802.11n)
  C. HR/DSSS (802.11b)
  D. HE (802.11ax)
  D. HE (802.11ax)

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  Explanation/Reference:

  The IEEE 802.11ax standard, also known as High-Efficiency Wireless (HEW) or simply HE, includes support for operation across multiple frequency bands: 2.4 GHz, 5 GHz, and, with the appropriate regulatory approvals, the 6 GHz band.

  This makes option D the correct answer. Here's how it compares to the other options:

  HE (802.11ax): Introduced as an enhancement over previous standards, 802.11ax is designed to improve efficiency, especially in dense environments. It supports operation in the 2.4 GHz, 5 GHz, and 6 GHz bands (the latter pending

  regulatory approval in various regions), making it highly versatile and future-proof. VHT (802.11ac): Very High Throughput, or 802.11ac, operates exclusively in the 5 GHz band. It introduced significant speed improvements over its

  predecessor (802.11n) but does not support the 2.4 GHz or 6 GHz bands. HT (802.11n): High Throughput, or 802.11n, supports operation in both the 2.4 GHz and 5 GHz bands. However, it does not include support for the 6 GHz band. HR/

  DSSS (802.11b): High-Rate Direct Sequence Spread Spectrum, or 802.11b, operates only in the 2.4 GHz band. It was one of the early Wi-Fi standards and does not support 5 GHz or 6 GHz bands.

  Given these distinctions, only 802.11ax (option D) supports operation across all three mentioned bands, aligning with the requirements stated in the question.

  References:

  IEEE 802.11ax-2021: High-Efficiency Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications.

  Understanding the 802.11ax (Wi-Fi 6) standard and its implications for modern wireless networking.

• Question 86:

  What statement about 802.3, Clause 33 Power over Ethernet is true?

  A. When using CAT5 cabling, you increase the maximum draw available to the PD over that available with CAT6.
  B. Only endpoint PSEs are supported.
  C. Only midspan PSEs are supported.
  D. The lowest voltage drop is achieved when using CAT6 cable instead of Cat5 or CAT5e.
  D. The lowest voltage drop is achieved when using CAT6 cable instead of Cat5 or CAT5e.

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  Explanation/Reference:

  https://www.cablinginstall.com/articles/2012/08/cat-6a-vs-cat-5e-poe.html The statement that the lowest voltage drop is achieved when using CAT6 cable instead of Cat5 or CAT5e is true about 802.3, Clause 33 Power over Ethernet. Power over Ethernet (PoE) is a technology that allows electrical power to be delivered over Ethernet cables along with data signals. PoE is defined by IEEE 802.3, Clause 33 and has several variants, such as PoE (802.3af), PoE+ (802.3at), and PoE ++ (802.3bt). PoE works by using a device called PSE (Power Sourcing Equipment) that injects power into the Ethernet cable and a device called PD (Powered Device) that receives power from the Ethernet cable. The PSE can be either an endpoint device, such as a switch or a router, or a midspan device, such as an injector or a splitter, that is inserted between two Ethernet devices. The PD can be any device that requires power, such as an access point, a camera, or a phone. One of the factors that affects PoE performance is voltage drop, which is the reduction of voltage that occurs as current flows through a cable due to its resistance. Voltage drop can cause power loss and inefficiency in PoE systems, as well as damage to PDs if the voltage falls below their minimum requirement. To minimize voltage drop, it is recommended to use high-quality cables with low resistance and short length. Among the common types of Ethernet cables, CAT6 has the lowest resistance and therefore the lowest voltage drop compared to Cat5 or CAT5e. CAT6 also has higher bandwidth and data rate than Cat5 or CAT5e, making it more suitable for PoE applications. References: 1, Chapter 7, page 263; 2, Section 4.4

• Question 87:

  What common feature of MDM solutions can be used to protect enterprise data on mobile devices?

  A. Over-the-air registration
  B. Onboarding
  C. Containerization
  D. Self-registration
  C. Containerization

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  Explanation/Reference:

  A common feature of MDM solutions that can be used to protect enterprise data on mobile devices is containerization. Containerization is a technique that creates a separate and secure environment on the mobile device where enterprise data and applications are stored and accessed. Containerization isolates the enterprise data from the personal data and prevents unauthorized access, leakage, or loss of sensitive information. Containerization can also enforce security policies, encryption, authentication, and remote wipe on the enterprise data and applications. Over-the-air registration, onboarding, and self-registration are features of MDM solutions that facilitate the enrollment and management of mobile devices, but they do not directly protect enterprise data on mobile devices. References: [CWNP Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 336; [CWNA: Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 326.

• Question 88:

  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
  B. DHCP

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  Explanation/Reference:

  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

• Question 89:

  In a long-distance RF link, what statement about Fade Margin is true?

  A. A Fade Margin is unnecessary on a long-distance RF link if more than 80% of the first Fresnel zone is clear of obstructions.
  B. The Fade Margin is a measurement of signal loss through free space and is a function of frequency and distance.
  C. Fade Margin is an additional pad of signal strength designed into the RF system to compensate for unpredictable signal fading.
  D. The Fade Margin of a long-distance radio link should be equivalent to the receiver's low noise filter gain.
  C. Fade Margin is an additional pad of signal strength designed into the RF system to compensate for unpredictable signal fading.

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  Explanation/Reference:

  Fade Margin is an additional pad of signal strength designed into the RF system to compensate for unpredictable signal fading. It is the difference between the receiver's sensitivity and the actual received signal level. A higher Fade Margin indicates a more robust link that can withstand interference, attenuation, or other factors that may reduce the signal strength. A lower Fade Margin means that the link is more susceptible to failure or performance degradation. Fade Margin is usually expressed in decibels (dB) and can be calculated by subtracting the receiver sensitivity from the received signal level. References: 1, Chapter 2, page 51; 2, Section 2.1

• Question 90:

  In an 802.11n (H T) 2.4 GHz BSS, what prevents each station from using all the airtime when other client stations are actively communicating in the same BSS?

  A. 802.11 DOS prevention
  B. OFDMA
  C. CSMA/CD
  D. CSMA/CA
  D. CSMA/CA

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  Explanation/Reference:

  What prevents each station from using all the airtime when other client stations are actively communicating in the same BSS is CSMA/CA. CSMA/CA stands for Carrier Sense Multiple Access with Collision Avoidance and is a media access control method used by WLAN devices to share the wireless medium. CSMA/CA works by having each station sense the medium before transmitting a frame. If the medium is busy (i.e., another station is transmitting), the station defers its transmission until the medium is idle. If the medium is idle, the station waits for a random backoff period before transmitting. This way, CSMA/CA reduces the chances of collisions and ensures fair access to the medium for all stations. CSMA/ CA also uses positive acknowledgements to confirm successful transmissions and retransmissions to recover from errors. CSMA/CD, DOS prevention, and OFDMA are not used by WLAN devices in a BSS. References: [CWNP Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 108; [CWNA: Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 98.