CWNA-109のPDF問題集で2025年12月07日最近更新された問題
CWNA-109試験問題有効なCWNA-109問題集PDF
CWNP CWNA-109 認定試験の出題範囲：
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質問 # 21
You are troubleshooting a WLAN problem and you suspect hidden node as the cause. What should you look for in a protocol analyzer?
- A. Frames with the retry bit set to 0
- B. Frames transmitted from the AP without acknowledgement
- C. Retransmitted frames from multiple STAs with higher retry counts than other STAs Frames with the HN bit set to 1
正解：C
解説：
The CWNA Official Study Guide (CWNA-109), Chapter 8: Troubleshooting and Spectrum Analysis, explains that hidden node problems occur when two or more client stations cannot hear each other but can both communicate with the same access point. This leads to collisions at the AP because the clients transmit simultaneously without sensing each other's signals.
"Hidden node problems can often be identified in a protocol analyzer by observing excessive retransmissions from specific client stations. These retransmissions occur because the station's frames are not acknowledged due to collisions caused by other stations that the transmitter cannot hear."
- CWNA-108 Study Guide, Chapter 8, Hidden Node Problem Analysis, p. 393-395 Therefore, when analyzing for a hidden node issue, you will typically observe:
* Retransmitted frames from multiple STAs.
* Higher retry counts for affected stations compared to others.
Hence, the correct answer is C. Retransmitted frames from multiple STAs with higher retry counts than other STAs.
質問 # 22
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. Elevators
- C. Cubicle partitions
- D. Carpeted floors
正解：B
解説：
Elevators are a common building item that frequently causes RF shadow and must be accounted for in coverage plans. RF shadow is a term that describes an area where wireless signals are blocked or significantly weakened by an obstacle or an object that absorbs or reflects RF energy. RF shadow can cause lack of coverage or poor performance in a WLAN because wireless devices in those areas may not be able to communicate with access points or other devices. RF shadow can be mitigated by adjusting access point placement, antenna orientation, transmit power level, or channel selection to avoid or overcome the obstacle or object that causes it. Elevators are a common building item that frequently causes RF shadow because they are made of metal and they move up and down within a shaft. Metal is a material that has high attenuation and reflection values, which means it can block or bounce off wireless signals very effectively. A moving elevator can create dynamic RF shadow that changes depending on its position and direction. Therefore, elevators must be accounted for in coverage plans to ensure adequate WLAN coverage and performance throughout the facility. The other options are not common building items that frequently cause RF shadow or must be accounted for in coverage plans. Wooden doors are not likely to cause RF shadow because they are made of wood, which is a material that has low attenuation and reflection values, which means it can pass through or slightly weaken wireless signals. Carpeted floors are not likely to cause RF shadow because they are made of fabric, which is a material that has low attenuation and reflection values, which means it can pass through or slightly weaken wireless signals. Cubicle partitions are not likely to cause RF shadow because they are made of thin plastic or cardboard, which are materials that have low attenuation and reflection values, which means they can pass through or slightly weaken wireless signals. References: CWNA-109 Study Guide, Chapter 13:
Wireless LAN Site Surveys - Types & Processes , page 433
質問 # 23
Which one of the following is not a factor considered when calculating the Link Budget for an outdoor point-to- point WLAN bridge link?
- A. Receive antenna gain
- B. MU-MIMO capabilities of the bridges
- C. Operating frequency
- D. Transmit power
正解：B
解説：
MU-MIMO capabilities of the bridges are not a factor considered when calculating the Link Budget for an outdoor point-to-point WLAN bridge link. The Link Budget is acalculation of the expected signal strength at the receiver based on various factors that affect the RF transmission. Some of these factors are operating frequency, transmit power, receive antenna gain, free space path loss, cable loss, connector loss, and environmental loss. MU-MIMO stands for Multi-User Multiple Input Multiple Output, which is a technology that allows multiple devices to communicate simultaneously using multiple spatial streams. MU-MIMO is not relevant for a point-to-point link, where there are only two devices involved. References: 1, Chapter 2, page
59; 2, Section 2.2
質問 # 24
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. AP hosts file
- C. DNS
- D. NTP
正解：C
解説：
What should be inspected to verify proper configuration is DNS. DNS stands for Domain Name System and is a service that resolves hostnames to IP addresses. In a controller-based AP deployment, DNS can be used to help the AP locate the controller by using a predefined hostname such as CISCO-CAPWAP-CONTROLLER or aruba-master. The AP sends a DNS query for this hostname and receives an IP address of the controller as a response. Therefore, if DNS is not configured properly or if there is no DNS entry for the controller hostname, the AP may not be able to locate the controller. NTP, BOOTP, and AP hosts file are not relevant for this scenario. References: [CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 374; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 364.
質問 # 25
ABC Company is planning to install a new 802.11ac WLAN, but wants to upgrade its wired infrastructure first to provide the best user experience possible. ABC Company has hired you to perform the RF site survey.
During the interview with the network manager, you are told that the new Ethernet edge switches will support VoIP phones and 802.11 access points, both using 802.3 PoE.
After hearing this information, what immediate concerns do you note?
- A. The power budget in the edge switches must be carefully planned and monitored based on the number of supported PoE devices.
- B. VoIP phones and 802.11 access points should not be powered by the same edge switch due to distortion.
- C. The edge Ethernet switches should support Ether-channel to get the best results out of the network.
- D. If the switches are in optimal locations for VoIP phones, they are likely to be suboptimal locations for
802.11 APs
正解：A
解説：
An immediate concern that you note after hearing this information is that the power budget in the edge switches must be carefully planned and monitored based on the number of supported PoE devices. PoE stands for Power over Ethernet and is a technology that allows Ethernet switches to deliver power along with data to devices such as VoIP phones and 802.11 access points. PoE devices are classified into different classes based on their power consumption and output. The edge switches have a limited power budget that determines how many PoE devices they can support simultaneously. If the power budget is exceeded, some PoE devices may not receive enough power or may shut down unexpectedly. Therefore, it is important to plan and monitor the power budget in the edge switches based on the number and class of PoE devices connected to them. Using Ether-channel, placing switches in optimal locations, or avoiding distortion are not immediate concerns related to PoE devices. References: [CWNP Certified Wireless Network Administrator Official Study Guide:
Exam CWNA-109], page 234; [CWNA: Certified Wireless Network Administrator Official Study Guide:
Exam CWNA-109], page 224.
質問 # 26
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. Create a plan of action or escalate the problem
- B. Verify the solution
- C. Perform corrective actions
- D. Discover the scale of the problem
正解：D
解説：
Discovering the scale of the problem is the next logical step in the troubleshooting process after identifying the problem of poor wireless connections on the third floor of a building under your administration.
Troubleshooting is a systematic process of finding and resolving problems or issues in a network or a system.
Troubleshooting usually follows a general methodology that consists of several steps or phases, such as:
* Identifying the problem: This step involves defining and describing the problem clearly and accurately based on the symptoms and evidence observed or reported by users or administrators. For example, in this case, the problem is that three individuals have reported poor wireless connections on the third floor of a building.
* Discovering the scale of the problem: This step involves determining how widespread and severe the problem is by gathering more information anddata from different sources and perspectives. For example, in this case, this step could involve checking if other users or devices on the third floor or other floors are experiencing similar issues, verifying if there are any changes or updates in the network configuration or environment that could affect the wireless connections, testing if there are any differences in performance or quality between different access points or channels on the third floor, etc.
* Performing corrective actions: This step involves applying possible solutions or fixes to resolve or mitigate the problem based on logical reasoning and analysis. For example, in this case, this step could involve adjusting the output power or channel assignment of the access points on the third floor, relocating or reorienting some access points or antennas to improve coverage or reduce interference, updating or replacing some faulty or outdated hardware or software components, etc.
* Verifying the solution: This step involves confirming that the problem is solved or improved by testing and monitoring the network performance and user satisfaction after applying corrective actions. For example, in this case, this step could involve measuring and comparing the signal strength and throughput of wireless connections on the third floor before and after performing corrective actions, asking for feedback from users who reported poor wireless connections to see if their issues are resolved or reduced, etc.
* Creating a plan of action or escalating the problem: This step involves documenting and reporting the problem and its solution for future reference and improvement purposes. It also involves deciding whether to close or escalate the problem depending on its status and severity. For example, in this case, this step could involve creating a report that summarizes what was done to troubleshoot and fix poor wireless connections on the third floor with relevant data and evidence to support it. It could also involve escalating poor wireless connections to higher-level administrators if they persist or worsen despite performing corrective actions.
References: 1, Chapter 12, page
質問 # 27
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. Capacity analysis results
- B. Application Layer protocol availability analysis results
- C. Layer 4 protocol availability analysis results
- D. WAN interface analysis results
正解：A
解説：
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.
質問 # 28
You are troubleshooting a client issue on a Windows laptop. The laptop can see and connect to 2.4 GHz APs, but is does not even see 5 GHz APs. While evaluating the issue, you determine that this problem is happening for all of the laptops of this model in the organization. Several other tablets connect on channel 48 and channel 52 in the same work areas. What is the likely problem?
- A. The clients are configured to use WPA and 5 GHz channels only support WPA2.
- B. The client drivers are faulty and should be upgraded.
- C. The access points are configured to disallow 5 GHz.
- D. The antennas in the laptop have insufficient gain to detect the 5 GHz signals.
正解：B
解説：
The client drivers are faulty and should be upgraded is the likely problem for the laptop that can see and connect to 2.4 GHz APs, but does not even see 5 GHz APs. The client drivers are the software components that enable the wireless adapter of the laptop to communicate with the operating system and the network. The client drivers are responsible for scanning the available wireless channels, detecting and connecting to the access points, negotiating the security and data rate parameters, and transmitting and receiving data frames. If the client drivers are faulty, outdated, or incompatible, they may cause various issues with the wireless performance and functionality, such as low data rates, poor signal strength, frequent disconnections, or inability to see or connect to certain access points or channels.
One of the possible causes of faulty client drivers is that they do not support or recognize some of the features or standards of the 802.11ac technology, such as wider channel bandwidths, higher modulation schemes, or DFS (Dynamic Frequency Selection) channels. This could explain why the laptop can see and connect to 2.4 GHz APs, but not 5 GHz APs, as 802.11ac operates only in the 5 GHz band and uses channels that are wider (up to 160 MHz) and higher (up to channel 165) than those used by previous standards. Moreover, some of the 5 GHz channels are subject to DFS rules, which require the access points and client stations to monitor and avoid using channels that are occupied by radar systems or other primary users. If the client drivers do not support or comply with DFS rules, they may not be able to see or connect to access points that use DFS channels.
To solve this problem, the client drivers should be upgraded to the latest version that supports and is compatible with 802.11ac features and standards. This can be done by downloading and installing the updated driver software from the manufacturer's website or using a device manager tool. Upgrading the client drivers may also improve other aspects of wireless performance and functionality, such as data rates, signal strength, security, and stability. References: 1, Chapter 12, page 493; 2, Section 8.1
質問 # 29
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. 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.
- B. 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.
- C. 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.
- D. 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.
正解：D
解説：
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
質問 # 30
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. UL-MU-MIMO
- B. BSS Color
- C. TWT
- D. OFDMA
正解：C
解説：
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
質問 # 31
What 802.11 PHY uses available space in very low frequency ranges that is not in use at the time by broadcast video signals?
- A. DMG
- B. DSSS
- C. TVHT
- D. SIG
正解：C
解説：
TVHT stands for Television Very High Throughput and it is a PHY defined by the 802.11af amendment. It uses the TV white space (TVWS) spectrum in the VHF and UHF bands between 54 and 790 MHz, which are not in use by broadcast video signals at the time. It can provide long-range and low-power connectivity for WLAN devices.
質問 # 32
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. Channel 1, because it is best to use the channel with the lowest frequency
- C. A 5 GHz channel, because channels 1 and 6 are 2.4 GHz channels they have no impact on the decision
- D. Channel 11, because channels 1 and 6 are in use nearby
正解：C
解説：
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
質問 # 33
You are tasked with performing a throughput test on the WLAN. The manager asks that you use open source tools to reduce costs. What open source tool is designed to perform a throughput test?
- A. IxChariot
- B. PuTTy
- C. Python
- D. iPerf
正解：D
解説：
iPerf is an open source tool that is designed to perform a throughput test on the WLAN. iPerf is a cross-platform command-line tool that can measure the bandwidth and quality of network links by generating TCP or UDP traffic between two endpoints.iPerf can run as either a server or a client mode, depending on whether it receives or sends traffic. iPerf can also report various metrics of network performance, such as throughput, jitter, packet loss, delay, and TCP window size. To perform a throughput test on the WLAN using iPerf, one device needs to run iPerf in server mode and another device needs to run iPerf in client mode. The devices need to be connected to the same WLAN network and have their IP addresses configured properly.
The device running iPerf in client mode needs to specify the IP address of the device running iPerf in server mode as well as other parameters such as protocol, port number, duration, interval, bandwidth limit, packet size, etc. The device running iPerf in server mode will listen for incoming connections from the client device and send back acknowledgments or responses depending on the protocol used. The device running iPerf in client mode will send traffic to the server device according to the specified parameters and measure the network performance. The device running iPerf in client mode will display the results of the throughput test at the end of the test or at regular intervals during the test. The results can show the average, minimum, maximum, and instantaneous throughput of the network link, as well as other metrics such as jitter, packet loss, delay, and TCP window size. References: 1, Chapter 7, page 287; 2, Section 4.3
質問 # 34
What cipher suite is specified by the 802.11-2016 standard and is not deprecated?
- A. Counter Mode with CBC-MAC Pro tocol
- B. Temporal Key Integrity Protocol
- C. Extensible Authentication Protocol
- D. Wired Equivalent Privacy
正解：A
解説：
The cipher suite specified by the 802.11-2016 standard and is not deprecated is Counter Mode with CBC-MAC Protocol (CCMP). CCMP is an encryption protocol that uses Advanced Encryption Standard (AES) as the underlying cipher and provides confidentiality, integrity, and origin authentication for wireless data. CCMP is the mandatory encryption protocol for WPA2 and WPA3. References: [CWNP Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 295; [IEEE Standard for Information technology-Telecommunications and information exchange between systems Local and metropolitan area networks-Specific requirements - Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications], page 1560.
質問 # 35
You are evaluating a connection that states the data rate is 150 Mbps. What is the expected throughput of this connection?
- A. 54 Mbps because that is the actual maximum throughput of an 802.11 connection
- B. 150 Mbps because the data rate is equal to the throughput
- C. More than 150 Mbps because of compression
- D. Less than 150 Mbps because of 802.11 overhead and contention
正解：D
解説：
The data rate of a signal is the speed that the data bits in individual 802.11 data frames are sent, but it does not account for the actual amount of data that can be transmitted over time. The throughput of a connection is the flow of information over time, which is affected by various factors such as data encoding, modulation, encryption, airtime utilization, noise levels, interference, etc. Therefore, the throughput is always lower than the data rate. According to one of the web search results1, the actual throughput is normally 60-70 percent of the supported data rates. So, for a connection with a data rate of 150 Mbps, the expected throughput would be around 90-105 Mbps.
質問 # 36
You have been tasked with creating a wireless link between two buildings on a single campus. The link must support at least 150 Mbps data rates. What kind of WLAN technology role should you deploy?
- A. Access BSS
- B. WPAN
- C. IBSS
- D. Wireless bridging
正解：D
解説：
https://www.wlanmall.com/what-is-a-wireless-bridge/
Wireless bridging is a WLAN technology role that allows two or more networks to be connected wirelessly over a distance. A wireless bridge consists of two or more APs that are configured to operate in bridge mode and use directional antennas to establish a point-to-point or point-to-multipoint link. Wireless bridging can support high data rates and is suitable for scenarios where running cables is impractical or expensive. To create a wireless link between two buildings on a single campus that supports at least 150 Mbps data rates, wireless bridging is an appropriate solution678. References: CWNA-109 Study Guide, Chapter 6: Wireless LAN Devices and Topologies, page 271; CWNA-109Study Guide, Chapter 6: Wireless LAN Devices and Topologies, page 265; Wi-Fi Wireless Bridging Explained.
質問 # 37
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