Free CWNA-109 Practice Test Questions and Answers (2026) | Cert Empire Practice Questions

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. Reference: , Chapter 3, page 103; , Section 3.1

Return loss is a measure of how well the components of an RF system are matched in terms of their

impedance. Impedance is the opposition to the flow of alternating current in a circuit, and it depends

on the frequency, resistance, capacitance, and inductance of the components. When the impedance

of the source, the transmission line, and the load are not equal, some of the power is reflected back

to the source, causing a loss of forward power. This loss is expressed in decibels (dB) as return loss.

The higher the return loss, the lower the reflection and the better the impedance matching.

Conversely, the lower the return loss, the higher the reflection and the worse the impedance

matching.

VSWR (Voltage Standing Wave Ratio) is another way of expressing the same concept. It is the ratio of

the maximum voltage to the minimum voltage along a transmission line due to the interference of

the incident and reflected waves. A VSWR of 1:1 means that there is no reflection and perfect

impedance matching. A VSWR higher than 1:1 means that there is some reflection and impedance

mismatch. The higher the VSWR, the higher the reflection and the lower the return loss.

Therefore, a significant impedance mismatch between components in an RF system will cause high

reflection, high VSWR, and low return loss.

The two IEEE amendments that should be supported to provide the management frame protection

and fast secure roaming security features are 802.11r and 802.11w12.

802.11r (Fast BSS Transition): This amendment to the IEEE 802.11 standard permits continuous

connectivity aboard wireless devices in motion, with fast and secure client transitions from one Basic

Service Set to another1.

802.11w (Management Frame Protection): This amendment increases the security of its

management frames2.

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. Reference: [CWNP

Certified Wireless Network Administrator Official Study Guide: Exam CWNA-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.

The unit of measurement that is an absolute unit and is used to quantify received signal power levels

on a logarithmic scale is dBm. dBm stands for decibel-milliwatt and represents the power level

relative to 1 milliwatt (mW). dBm is an absolute unit because it has a fixed reference point and does

not depend on the input power level. dBm is used to measure the received signal power levels on a

logarithmic scale because it can express large variations in power levels with small numbers and

make calculations easier. For example, a 10 dB increase in power level means a 10-fold increase in

power, and a 20 dB increase means a 100-fold increase in power. Reference: [CWNP Certified

Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 66; [CWNA: Certified

Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 56.

Authenticated and Unassociated. According to one of the web search results1, a STA can be

authenticated to multiple APs, but it can only be associated to one AP at a time. Association is the

process of establishing a logical link between the STA and the AP, which allows the STA to send and

receive data frames through the AP2. Therefore, when a STA has authenticated to an AP-1, but still

maintains a connection with another AP-2, it means that the STA is authenticated to both APs, but

only associated to AP-2. The state of the STA on AP-1 is authenticated and unassociated, which

means that the STA can switch to AP-1 without repeating the authentication process, but it cannot

send or receive data frames through AP-1 until it becomes associated.

What prevents each station from using all the airtime when other client stations are actively

communicating in the same BSS is CSMA/C

A . 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. Reference: [CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-

109], page 108; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-

109], page 98.

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. Reference: [CWNP Certified Wireless Network Administrator Official Study Guide: Exam

CWNA-109], page 403; [Role-Based Access Control (RBAC) in Wireless Networks], page 1.

802.11 QoS is achieved by giving high priority queues a statistical advantage at winning contention.

802.11 QoS is based on the Enhanced Distributed Channel Access (EDCA) mechanism, which defines

four access categories (ACs) for different types of traffic: Voice, Video, Best Effort, and Background.

Each AC has its own transmit queue and contention parameters, such as Arbitration Interframe

Space (AIFS), Contention Window (CW), and Transmission Opportunity (TXOP). These parameters

determine how long a station has to wait before transmitting a frame and how long it can occupy the

channel. Higher priority ACs have shorter AIFS, smaller CW, and longer TXOP, which means they have

more chances to access the channel and send more data than lower priority ACs. However, this does

not guarantee that higher priority ACs will always win the contention, as there is still a random

backoff process involved. Therefore, 802.11 QoS is a statistical service that provides different levels

of service quality based on traffic categories. Reference: , Chapter 10, page 403; , Section 6.1

Patch and panel antennas are directional antenna types that are commonly used by indoor Wi-Fi

devices in a MIMO multiple spatial stream implementation. These antennas have a flat rectangular

shape and can be mounted on walls or ceilings to provide coverage in a specific direction. They have

a moderate gain and a relatively wide beamwidth, making them suitable for multipath environments

where signals can reflect off different surfaces and create multiple spatial streams. Patch and panel

antennas can also support polarization diversity, which means they can transmit and receive both

horizontally and vertically polarized waves, increasing the MIMO performance. Reference: 1, Chapter

2, page 72; 2, Section 2.4

The authentication method that is referenced in the 802.11-2016 and 802.11-2020 specifications and

is recommended for robust WLAN client security is 802.1X/EAP. 802.1X/EAP stands for IEEE 802.1X

Port-Based Network Access Control with Extensible Authentication Protocol and is a framework that

provides strong authentication and dynamic encryption key generation for WLAN clients. 802.1X/EAP

involves three parties: the supplicant (the client), the authenticator (the AP or the controller), and

the authentication server (usually a RADIUS server). The supplicant sends its credentials (such as

username and password, certificate, or token) to the authenticator, which forwards them to the

authentication server. The authentication server verifies the credentials and sends a response to the

authenticator, which grants or denies access to the supplicant. The authentication server also

generates a master key that is used to derive encryption keys for the data frames between the

supplicant and the authenticator. 802.1X/EAP supports various EAP methods that offer different

levels of security and flexibility, such as EAP-TLS, EAP-PEAP, EAP-TTLS, EAP-FAST, and EAP-SIM. SSL,

IPSec, and WEP are not authentication methods, but rather encryption or security protocols that are

not specific to WLANs or referenced in the 802.11 specifications. Reference: [CWNP Certified

Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 299; [CWNA: Certified

Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 289.

When performing a post-deployment validation survey for voice over Wi-Fi (VoWiFi), an action that

must be performed is Application analysis with an active phone call on a VoWiFi handset. Application

analysis is a method of testing the performance of a specific application over the WLAN by

measuring parameters such as throughput, latency, jitter, packet loss, MOS score, and R-value.

Application analysis with an active phone call on a VoWiFi handset can help to evaluate the quality of

service (QoS) and user experience of VoWiFi calls over the WLAN. It can also help to identify any

issues or bottlenecks that may affect VoWiFi calls such as interference, roaming delays, or insufficient

coverage. Reference: [CWNP Certified Wireless Network Administrator Official Study Guide: Exam

CWNA-109], page 549; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam

CWNA-109], page 519.

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.

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. Reference: , Chapter 1, page 23; , Section 1.1

The inverse square law states that the signal strength of an RF wave is inversely proportional to the

square of the distance from the source. This means that as the distance from the transmitter

increases, the signal strength decreases rapidly.

Reference: Wireless Network Administrator Official Study Guide, Chapter 3, page 64.

The factors that will have the most significant impact on the amount of wireless bandwidth available

to each station within a BSS are:

The number of client stations associated to the BSS

The presence of co-located (10m away) access points on non-overlapping channels

The number of client stations associated to the BSS affects the wireless bandwidth because each

station shares the same channel and medium with other stations in the same BSS. The more stations

there are, the more contention and collision there will be for the channel access, which reduces the

throughput and efficiency of the wireless communication. The wireless bandwidth available to each

station depends on how the access point allocates the channel resources and how the stations use

the channel time. For example, if the access point uses a round-robin scheduling algorithm, each

station will get an equal share of the channel time regardless of its data rate or traffic demand.

However, if the access point uses a proportional fair scheduling algorithm, each station will get a

share of the channel time that is proportional to its data rate and traffic demand, which may result in

higher or lower bandwidth for different stations.

The presence of co-located (10m away) access points on non-overlapping channels affects the

wireless bandwidth because even though they use different channels, they may still cause

interference and noise to each other due to channel leakage or imperfect filtering. The interference

and noise can degrade the signal quality and SNR of the wireless communication, which reduces the

data rate and throughput of the wireless communication. The wireless bandwidth available to each

station depends on how well the access point and the station can cope with the interference and

noise from other channels. For example, if the access point and the station support dynamic

frequency selection (DFS) or adaptive radio management (ARM), they can switch to a less congested

channel or adjust their output power or antenna gain to avoid or minimize interference from other

channels.

Reference: 1, Chapter 3, page 94; 2, Section 3.2

Impedance is the measure of opposition to the flow of alternating current (AC) in a circuit.

Impedance mismatch occurs when the impedance of the radio does not match the impedance of the

antenna or the cable. This causes some of the transmitted or received signal to be reflected back,

resulting in a loss of power and efficiency. The voltage standing wave ratio (VSWR) is a metric that

indicates the amount of impedance mismatch in a transmission line. A higher VSWR means a higher

impedance mismatch and a lower signal quality. A VSWR of 1:1 is ideal, meaning there is no

impedance mismatch and no reflected power. A VSWR of 2:1 means that for every 2 units of forward

power, there is 1 unit of reflected power12.

The other options are not correct because they do not affect the VSWR in RF cables. A high gain yagi

antenna or a high gain parabolic dish antenna can increase the signal strength and directionality, but

they do not cause impedance mismatch in the cable. Radio output power above 100 mW but below

400 mW is within the acceptable range for most WLAN devices and does not cause excessive VSWR

in the cable3.

Reference: 1: CWNA-109 Official Study Guide, page 77 2: VSWR 3: CWNA-109 Official Study Guide,

page 81

A pre-design site visit in preparation for a predictive wireless LAN design is essential for gathering

physical and environmental data about the site. The key tasks to be performed during such a visit

include:

Evaluating Building Materials: Different materials (concrete, glass, wood, etc.) have varying effects

on RF signal propagation. Understanding the materials present helps in accurately predicting how

signals will behave within the environment.

Floor Plan Verification: Ensuring that the floor plan documents are an accurate representation of the

actual building layout is crucial. Discrepancies between the floor plans and the physical layout can

lead to inaccuracies in the predictive design.

The other options, while potentially valuable in other contexts, are not directly related to preparing

for a predictive design:

Installing APs (option A) for testing co-channel interference is more aligned with an active site survey

rather than a pre-design visit for a predictive design.

Collecting information about security requirements (option B) is important but is not directly related

to the physical aspects of the site that would impact a predictive design.

Testing antenna types (option C) would typically be part of an active site survey or the actual

deployment phase, not a pre-design visit for predictive modeling.

Therefore, option D is the correct answer, focusing on evaluating physical aspects crucial for accurate

predictive modeling.

Reference:

CWNA Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109, by David D.

Coleman and David

A . Westcott.

Best practices for conducting pre-design site visits in wireless network planning.

An ACK (Acknowledgement) frame is a short control frame that is sent by the receiver of a data or

management frame to confirm that the frame was received correctly. The ACK frame is sent after a

SIFS (Short Interframe Space) interval, which is the shortest time gap between frames in 802.11. If

the transmitter does not receive an ACK frame within a specified time, it assumes that the frame was

not delivered and must be retransmitted. This is part of the 802.11 reliability mechanism that

ensures reliable data delivery over an unreliable wireless medium . Reference: [CWNA-109 Study

Guide], Chapter 5: IEEE 802.11 Medium Access, page 209; [CWNA-109 Study Guide], Chapter 5: IEEE

802.11 Medium Access, page 203.

OFDM is a modulation method that divides the channel bandwidth into multiple subcarriers, each

carrying a single data symbol. This allows for higher data rates and more robust transmissions in

multipath environments. OFDM was first introduced in the 802.11a standard, which operates in the 5

GHz band and supports data rates up to 54 Mbps. Later, the 802.11g standard adopted OFDM for the

2.4 GHz band, and the 802.11n and 802.11ac standards enhanced OFDM with features such as MIMO

(Multiple Input Multiple Output), channel bonding, and higher-order modulation schemes to achieve

data rates up to 600 Mbps and 6.9 Gbps, respectively. These standards are collectively known as the

ERP (Extended Rate PHY), HT (High Throughput), and VHT (Very High Throughput) PHYs

. Reference: [CWNA-109 Study Guide], Chapter 4: Radio Frequency Signal and Antenna Concepts,

page 163; [CWNA-109 Study Guide], Chapter 4: Radio Frequency Signal and Antenna Concepts, page

157.