CWNP CWNA-109 Online Practice Questions and Exam Preparation

CWNP CWNA-109 Online Questions & Answers

• Question 1:

  You are troubleshooting a problem with a new 802.11ax AP. While the AP supports four spatial streams, most clients are only achieving maximum data rates of 150 Mbps. What is the likely cause?

  A. The clients are 802.11n devices
  B. The clients are only two stream 802.11ax clients
  C. Contention caused by an overlapping BSS
  D. Non-Wi-Fi interference in the channel
  A. The clients are 802.11n devices

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  explanation:

  Explanation/Reference:

  The scenario described suggests that while the Access Point (AP) is capable of 802.11ax (Wi-Fi 6) with four spatial streams, the clients are only achieving data rates typical of 802.11n (Wi-Fi 4) devices, which indicates that the clients are

  likely 802.11n devices. Here's why this is the most plausible explanation:

  802.11n Limitations: Devices that adhere to the 802.11n standard have lower maximum data rates compared to 802.11ax devices due to differences in technology such as modulation, spatial streams, and channel bandwidth. An 802.11n

  device with a single spatial stream operating on a 20 MHz channel can achieve a maximum data rate of 72.2 Mbps. Even with two spatial streams under ideal conditions, this would only double to approximately 144.4 Mbps, which is close to

  the 150 Mbps mentioned.

  Spatial Stream Capability: The fact that the AP supports four spatial streams suggests it can achieve much higher data rates with 802.11ax clients that also support multiple spatial streams. However, if the clients are 802.11n devices, they

  may not be capable of using more than two spatial streams, and many earlier 802.11n devices were limited to just one.

  The other options are less likely to be the primary cause based on the information provided:

  B. Two Stream 802.11ax Clients: If the clients were 802.11ax with only two spatial streams, they would likely achieve higher data rates than 150 Mbps due to the efficiency improvements in 802.11ax.

  C. Contention and D. Non-Wi-Fi Interference: While these could affect performance, they would not inherently limit clients to 150 Mbps,especially in the context of an 802.11ax environment where mechanisms to handle interference and

  contention are more advanced.

  References:

  IEEE 802.11n-2009: Enhancements for Higher Throughput. CWNA Certified Wireless Network Administrator Official Study Guide: Exam PW0- 105, by David D. Coleman and David A. Westcott.

• Question 2:

  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:

  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 3:

  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:

  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

• Question 4:

  You are installing an AP to be used by 27 laptops. All laptops will connect on the 5 GHz frequency band. A neighbor network uses channels 1 and 6. What channel should be used for this AP and why?

  A. Channel 6, because it is always best to use this channel
  B. A 5 GHz channel, because channels 1 and 6 are 2.4 GHz channels they have no impact on the decision
  C. Channel 1, because it is best to use the channel with the lowest frequency
  D. Channel 11, because channels 1 and 6 are in use nearby
  B. A 5 GHz channel, because channels 1 and 6 are 2.4 GHz channels they have no impact on the decision

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  explanation:

  Explanation/Reference:

  A 5 GHz channel should be used for this AP because channels 1 and 6 are 2.4 GHz channels and they have no impact on the decision. The 5 GHz frequency band offers more non-overlapping channels than the 2.4 GHz frequency band, which reduces interference and improves performance. The 5 GHz frequency band also supports higher data rates and wider channel bandwidths than the 2.4 GHz frequency band, which increases capacity and throughput. The 5 GHz frequency band also has less interference from other devices and sources than the 2.4 GHz frequency band, which enhances reliability and quality of service. Therefore, it is recommended to use the 5 GHz frequency band for WLANs whenever possible. Channels 1 and 6 are two of the three non- overlapping channels in the 2.4 GHz frequency band (the other one is channel 11). They are used by a neighbor network in this scenario, but they do not affect the channel selection for this AP because they operate in a different frequency band than the 5 GHz frequency band. Channel 6 is not always best to use; it depends on the interference and congestion level in the environment. Channel 1 is not best to use because it has a lower frequency than channel 6; frequency does not determine channel quality or performance. Channel 11 is not best to use because it is also a 2.4 GHz channel and it may interfere with channels 1 and 6. References: CWNA-109 Study Guide, Chapter 4: Antenna Systems and Radio Frequency (RF) Components, page 113

• Question 5:

  To ease user complexity, your company has implemented a single SSID for all employees. However, the network administrator needs a way to control the network resources that can be accessed by each employee based in their department. What WLAN feature would allow the network administrator to accomplish this task?

  A. RBAC
  B. WPA2
  C. WIPS
  D. SNMP
  A. RBAC

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  explanation:

  Explanation/Reference:

  The WLAN feature that would allow the network administrator to control the network resources that can be accessed by each employee based on their department is Role-Based Access Control (RBAC). RBAC is a method of assigning different permissions and policies to users or groups based on their roles in the organization. RBAC can be implemented by using VLANs, ACLs, or firewalls to restrict access to certain network segments or resources. RBAC can also be integrated with 802.1X/EAP authentication to dynamically assign roles and VLANs to users based on their credentials. References: [CWNP Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 403; [Role-Based Access Control (RBAC) in Wireless Networks], page 1.

• Question 6:

  What is the most effective method for testing roaming in relation to 802.11 VoIP handsets?

  A. Use a spectrum analyzer to monitor RF activity during a VoIP call.
  B. Use a protocol analyzer to capture the traffic generated when a laptop roams.
  C. Place a call with the handset and move around the facility to test quality during roaming.
  D. Use the built-in roaming monitor built into all VoIP handsets.
  C. Place a call with the handset and move around the facility to test quality during roaming.

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  explanation:

  Explanation/Reference:

  The most effective method for testing roaming in relation to 802.11 VoIP handsets is to place a call with the handset and move around the facility to test quality duringroaming. This method allows you to evaluate the actual performance and user experience of VoIP calls over wireless networks, as well as identify any potential issues such as signal strength, interference, latency, jitter, packet loss, or handoff delays. A spectrum analyzer can only show you the RF activity during a VoIP call, but not how it affects the voice quality or roaming behavior. A protocol analyzer can capture the traffic generated when a laptop roams, but it cannot simulate the characteristics of a VoIP handset such as battery life, antenna design, codec support, or QoS features. A built-in roaming monitor is not a common feature in all VoIP handsets, and it may not provide accurate or comprehensive information about the roaming process. References: [CWNP Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 487; [Voice over Wireless LAN 4.1 Design Guide], page 6-19.

• Question 7:

  What is an advantage of using WPA3-Personal instead of WPA2-Personal as a security solution for 802.11 networks?

  A. WPA3-Personal, also called WPA3-SAE, uses an authentication exchange and WPA2- Personal does not
  B. WPA3-Personal, also called WPA3-SAE, uses a stronger authentication exchange to better secure the network
  C. WPA3-Personal, also called WPA3-SAE, uses AES for encryption and WPA2-Personal does not
  D. WPA3-Personal, also called WPA3-SAE, uses a better encryption algorithm than WPA2- Personal
  B. WPA3-Personal, also called WPA3-SAE, uses a stronger authentication exchange to better secure the network

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  explanation:

  Explanation/Reference:

  An advantage of using WPA3-Personal instead of WPA2-Personal as a security solution for 802.11 networks is that WPA3-Personal, also called WPA3-SAE, uses a stronger authentication exchange to better secure the network. WPA3Personal 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. SAE uses a Diffie-Hellman key exchange with elliptic curve cryptography (ECC) to establish a pairwise master key (PMK) between the AP and the client without revealing it to any eavesdropper. SAE also provides forward secrecy, which means that if one PMK is compromised, it does not affect the security of other PMKs. WPA2-Personal uses Pre- Shared Key (PSK) as the key exchangeprotocol, which is vulnerable to offline brute-force attacks if the passphrase is weak or leaked. Both WPA3Personal and WPA2-Personal use AES for encryption, so there is no difference in that aspect. WPA3-Personal does not use a different encryption algorithm than WPA2-Personal, but rather a different key exchange protocol. 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 8:

  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:

  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 9:

  The BSA of an AP covers the area used by the sales and marketing department. Thirty-five stations operate in this space. The users indicate that they need more throughput and all stations are 5 GHz capable 802.11ac clients. The current AP configuration uses 20 MHz channels in both 2.4 GHz and 5 GHz. What is the least expensive solution available for increasing throughput for these users without implementing configuration options that are not recommended?

  A. Use a 160 MHz channel on the 5 GHz radio
  B. Use a 40 MHz channel on the 5 GHz radio
  C. Install a second AP in the coverage area
  D. Use a 40 MHz channel on the 2.4 GHz radio
  B. Use a 40 MHz channel on the 5 GHz radio

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  explanation:

  Explanation/Reference:

  The least expensive solution available for increasing throughput for these users without implementing configuration options that are not recommended is to use a 40 MHz channel on the 5 GHz radio. This solution can double the channel bandwidth and increase the data rates for the 5 GHz capable 802.11ac clients. Using a 40 MHz channel on the 5 GHz radio is also less likely to cause co-channel interference or overlap with other channels than using a 40 MHz channel on the 2.4 GHz radio, which has only three non-overlapping channels. Using a 160 MHz channel on the 5 GHzradio may provide even higher throughput, but it may also consume too much of the available spectrum and cause more interference with other devices or networks. Installing a second AP in the coverage area may also improve the throughput, but it may require additional costs and configuration. References: [CWNP Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 216; [CWNA: Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 206.

• Question 10:

  When implementing PoE, what role is played by a switch?

  A. PSE
  B. Midspan injector
  C. PD
  D. Power splitter
  A. PSE

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  explanation:

  Explanation/Reference:

  PoE stands for Power over Ethernet, which is a technology that allows network devices to receive power and data over the same Ethernet cable. PoE eliminates the need for separate power adapters or outlets for devices such as IP phones, cameras, or APs. PoE requires two types of devices: PSE (Power Sourcing Equipment) and PD (Powered Device). A PSE is a device that provides power to the Ethernet cable, such as a switch, injector, or splitter. A PD is a device that receives power from the Ethernet cable, such as an IP phone, camera, or AP. When implementing PoE, a switch plays the role of a PSE910. References: CWNA-109 Study Guide, Chapter 7: Power over Ethernet (PoE), page 293; CWNA109Study Guide, Chapter 7: Power over Ethernet (PoE), page 287.