Key details for this exam, checked against the published exam outline
Each question shows the correct answer and an explanation of why it is right
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?
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.Reference:CWNA-109 Study Guide, Chapter 10: Wireless LAN Operation, page 323
You are configuring an access point to use channel 128. What important fact should be considered about this channel?
It is a channel that may require DFS when used is an important fact that should be considered about channel 128. Channel 128 is a 5 GHz frequency band 20 MHz channel that has a center frequency of 5.64 GHz. Channel 128 is one of the channels that are subject to DFS (Dynamic Frequency Selection) rules, which require Wi-Fi devices to monitor and avoid using channels that are occupied by radar systems or other primary users. DFS is a feature that is defined in the IEEE 802.11h amendment and is mandated by some regulatory bodies, such as the FCC and the ETSI, to protect the licensed users of the 5 GHz band from interference by unlicensed Wi-Fi devices. DFS works by using a mechanism called channel availability check (CAC), which requires Wi-Fi devices to scan a channel for a certain period of time before using it. If a radar signal is detected during the CAC or while using the channel, the Wi-Fi devices must switch to another channel that is free from radar interference.
When configuring an access point to use channel 128, it is important to consider the implications of DFS rules, such as:
The access point must support DFS and comply with the local regulations and standards that apply to DFS channels.
The access point may experience delays or interruptions in its operation due to CAC or channel switching.
The access point may have limited channel selection or availability due to radar interference or other Wi-Fi devices using DFS channels.
The access point may have compatibility or interoperability issues with some client devices that do not support DFS or use different DFS parameters.
The access point may have performance or quality issues due to co-channel or adjacent-channel interference from other Wi-Fi devices using non-DFS channels.
What is the most effective method for testing roaming in relation to 802.11 VoIP handsets?
The most effective method for testing roaming in relation to 802.11 VoIP handsets is toplace a call with the handset and move around the facility to test quality during roaming. 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.Reference:[CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 487; [Voice over Wireless LAN 4.1 Design Guide], page 6-19.
A WLAN transmitter that emits a 50 mW signal is connected to a cable with 3 dB loss. If the cable is connected to an antenna with 9dBi gain, what is the EIRP at the antenna element?
To calculate the EIRP at the antenna element, we need to add the transmitter output power, subtract the cable loss, and add the antenna gain. All these values need to be converted to dBm first, if they are not already given in that unit. In this case, we have:
Transmitter output power = 50 mW = 10 log (50) dBm = 16.99 dBm Cable loss = 3 dB Antenna gain = 9 dBi
EIRP = Transmitter output power - Cable loss + Antenna gain EIRP = 16.99 - 3 + 9 EIRP = 22.99 dBm
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 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.Reference:CWNA-109 Study Guide, Chapter 4: Antenna Systems and Radio Frequency (RF) Components, page 113
122 questions covering all exam domains, starting from $20
Exam domains verified against: Official CWNP CWNA-109 exam guide, last checked September 2026.
Understand RF basics, mathematics, and measurement including signal characteristics, antenna functionality, RF cables, connectors, grounding, and enclosures. This domain covers fundamental RF behavior needed for wireless network deployment and troubleshooting.
Sample question from this domain above: Q5
Learn the roles of IEEE, Wi-Fi Alliance, IETF, and regulatory agencies in setting WLAN standards. Study Physical Layer solutions from 802.11 through 802.11ax including DSSS, OFDM, and the latest Wi-Fi 6 technologies with their supported data rates and channel widths.
Sample question from this domain above: Q2
Master 802.11 MAC and PHY terminology, frame types and formats, and channel access methods. Know how wireless devices communicate using different frame structures and the protocols that govern access to the wireless medium.
Implement Power over Ethernet for access points and design wireless LAN architectures. Address coverage requirements, roaming considerations, and common proprietary features that enterprises use to optimize network performance.
Identify weak security options and implement enterprise WLAN security mechanisms. Evaluate security tools and options for wireless networks to protect against unauthorized access and data compromise.
Sample question from this domain above: Q4
Manage RF interference and optimize WLAN performance using validation tools. Troubleshoot common wireless issues through understanding tool features and applying remediation techniques for real-world network problems.
Common questions about the exam itself
