Correct Answer: C

The security option for 802.11 networks that supports SAE and requires protected management frames is WPA3. WPA3 stands for Wi-Fi Protected Access version 3 and is the latest security standard for WLANs. WPA3 supports two modes:

WPA3-Personal and WPA3-Enterprise. WPA3-Personal 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. WPA3 also requires protected management frames, which are encrypted frames that prevent spoofing, replay, or denial- of-service attacks on management frames such as deauthentication or disassociation frames. WPA,

WPA2, and OWE do not support SAE or require protected management frames. 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.

Correct Answer: C

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. References: 1, Chapter 2, page 72; 2, Section 2.4

Correct Answer: A

Weak signal strength is the likely cause of the low data rate issue for the client that has a signal strength of -84 dBm and a noise floor of -96 dBm. The client is an 802.11ac client and connects to an 802.11ac AP. Both the client and AP are 2x2:2 devices. Signal strength is the measure of how strong the RF signal is at the receiver. Signal strength can affect the reliability and performance of the wireless connection, as well as the data rate and throughput of the traffic. The higher the signal strength, the better the signal quality and the higher the data rate. The lower the signal strength, the worse the signal quality and the lower the data rate. The data rate of an 802.11ac connection depends on several factors, such as channel bandwidth, modulation and coding scheme (MCS), spatial streams, guard interval, and beamforming. However, these factors are also influenced by the signal strength, as they require a certain signal-to-noise ratio (SNR) to operate properly. SNR is the ratio of the signal strength to the noise floor, which is the measure of the background noise or interference in the RF environment. The higher the SNR, the more robust and efficient the communication. The lower the SNR, the more prone and vulnerable to errors and retries. According to the CWNA Official Study Guide , Table 3.7, page 112, an 802.11ac connection with a channel bandwidth of 80 MHz, an MCS of 9, two spatial streams, a short guard interval, and no beamforming can achieve a maximum data rate of 867 Mbps. However, this data rate requires a minimum SNR of 30 dB to maintain a sufficient signal quality. If the signal strength is -84 dBm and the noise floor is -96 dBm, then the SNR is only 12 dB (-84 dBm - (-96 dBm) = 12 dB), which is far below the required SNR for this data rate. Therefore, the data rate will drop significantly to match the lower SNR and signal quality. To solve this problem, the signal strength should be increased to improve the SNR and data rate. This can be done by adjusting the output power or channel assignment of the AP or client, relocating or reorienting some APs or antennas to reduce attenuation or interference, updating or replacing some faulty oroutdated hardware or software components, etc. References: , Chapter 3, page 112; , Section 3.2

Correct Answer: A

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: ExamCWNA-109], page 234; [CWNA: Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 224.

Correct Answer: C

Airtime Utilization is a per-channel statistic that defines what percentage of the channel is currently being used, and what percentage is therefore free. Airtime usage can come from:

Data traffic to and from client devices. Interference from WiFi and non-WiFi sources.

Management overhead from APs and client

devices.https://wyebot.com/2019/06/06/understanding-airtime-utilization/

Correct Answer: A

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.

Correct Answer: D

The FCS (Frame Check Sequence) is appended to the end of each 802.11 data frame after the payload. The FCS is a 4-byte field that contains a CRC-32 (Cyclic Redundancy Check) value that is calculated based on the contents of the MAC header and the payload of the frame. The FCS is used by the receiver to verify the integrity of the frame and to detect any errors or corruption that may have occurred during transmission. If the FCS does not match with the expected value, the frame is discarded by the receiver. References: , Chapter 4, page 139; , Section 4.2

Correct Answer: A

When a station scans for available wireless networks, it listens for beacon frames sent by APs. A beacon frame contains information about the BSS, such as SSID, supported rates, channel, security, etc. The station also measures the signal strength of the beacon frames, which indicates how well the station can communicate with the AP. The signal strength is usually expressed in dBm or RSSI units. The higher the signal strength, the better the connection quality and performance. Therefore, the station can use the signal strength of AP beacons as the primary metric to select the best AP for connectivity to the desired BSS12. References: CWNA-109 Study Guide, Chapter 6: Wireless LAN Devices and Topologies, page 249; CWNA-109Study Guide, Chapter 6: Wireless LAN Devices and Topologies, page 243.

Correct Answer: D

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.

Correct Answer: A

The frame type that is used to reserve the wireless medium for the transmission of high data rate frames that may not be understood by all clients connected to the BSS is RTS. RTS stands for Request to Send and is a control frame that is sent by a station to request access to the medium for a specified duration. The RTS frame contains the source and destination MAC addresses, as well as a Network Allocation Vector (NAV) value that indicates how long the medium will be occupied. The destination station responds with a Clear to Send (CTS) frame that echoes the NAV value and grants permission to the source station. All other stations in the BSS hear either the RTS or CTS frame and update their NAV timers accordingly, deferring their transmissions until the medium is free. The RTS/CTS mechanism can be used to prevent hidden node problems, reduce collisions, and protect high data rate frames that use features such as 802.11n or 802.11ac that may not be compatible with legacy stations. ACK, Beacon, and PS-Poll are not used to reserve the medium for high data rate frames. References: [CWNP Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 112; [CWNA: Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 102.