CWNA-109 Exam Dumps - Certified Wireless Network Administrator

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

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

Rounding up to the nearest integer, we get 23 dBm as the EIRP at the antenna element12. References: CWNA-109 Study Guide, Chapter 2: Radio Frequency Fundamentals, page 92; CWNA-109Study Guide, Chapter 2: Radio Frequency Fundamentals, page 88.

OFDMA is a new modulation scheme introduced in 802.11ax that allows multiple users to share the same channel by dividing it into smaller subchannels called resource units (RUs). This improves the efficiency and capacity of the WLAN by reducing contention and overhead. However, to use OFDMA, both the AP and the client must support 802.11ax and negotiate the parameters of the subchannel allocation. Therefore, the customer needs to upgrade the clients that require OFDMA to 802.11ax devices12.

The other options are not correct because they do not reflect the reality of OFDMA. Option B is incorrect because OFDMA is a mandatory feature of 802.11ax for both downlink and uplink transmissions, and all 802.11ax APs must support it1. Option C is incorrect because OFDM and OFDMA are different modulation schemes, and OFDM does not allow multiple users to share the same channel. Option D is incorrect because 802.11ac devices cannot support OFDMA through driver upgrades, as they lack the hardware and firmware capabilities to do so2.

References: 1:CWNA-109Official Study Guide, page 144 2: OFDMA

 VSWR stands for Voltage Standing Wave Ratio, which is a measure of how well the impedance of the RF cable and connectors matches the impedance of the transmitter and the antenna. Impedance is the opposition to the flow of alternating current in an RF circuit, and it depends on the frequency, resistance, capacitance, and inductance of the components. A perfect impedance match would have a VSWR of 1:1, meaning that all the power is transferred from the transmitter to the antenna, and none is reflected back. However, in reality, there is always some degree of mismatch, which causes some power to be reflected back to the transmitter, creating standing waves along the cable. This reduces the efficiency and performance of the wireless system, and can also damage the transmitter. Excessive VSWR can be caused by using poor quality or damaged cables and connectors, or by using components that have different impedance ratings123. References: CWNA-109 Study Guide, Chapter 2: Radio Frequency Fundamentals, page 90; CWNA-109Study Guide, Chapter 2: Radio Frequency Fundamentals, page 86; CWNP website, CWNA Certification.

 This is because the passphrase for WPA2-Personal is case-sensitive and must match exactly on both the AP and the client. If the passphrase is entered incorrectly on the client, the client will not be able to authenticate with the AP and connect to the network. The AP that covers the problem area is not likely to require a firmware update, fail, or be improperly configured, as it is online and works with other clients that have the correct passphrase. To troubleshoot this issue, you can check the passphrase settings on the clients and make sure they matchwith the AP. You can also try to reconnect the clients to the network or reboot them if necessary. For more information on how to configure WPA2-Personal on your router

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. References: [CWNP Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 299; [CWNA: Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 289.

SAE (Simultaneous Authentication of Equals) is required when operating 802.11ax APs in the 6 GHz band using passphrase-based authentication. SAE is a secure and robust authentication method that is defined in the IEEE 802.11s amendment and is also known as WPA3-Personal or WPA3-SAE. SAE is based on a cryptographic technique called Dragonfly Key Exchange, which allows two parties to establish a shared secret key using a passphrase, without revealing the passphrase or the key to an eavesdropper or an attacker. SAE also provides forward secrecy, which means that if the passphrase or the key is compromised in the future, it does not affect the security of past communications.

SAE is required when operating 802.11ax APs in the 6 GHz band using passphrase-based authentication because of the new regulations and standards that apply to this band. The 6 GHz band is a new frequency band that was opened for unlicensed use by the FCC and other regulatory bodies in 2020. The 6 GHz band offers more spectrum and less interference than the existing 2.4 GHz and 5 GHz bands, which can enable higher performance and efficiency for Wi-Fi devices. However, the 6 GHz band also has some restrictions and requirements that are different from the other bands, such as:

• The 6 GHz band is divided into two sub-bands: U-NII-5 (5925-6425 MHz) and U-NII-7 (6525-6875 MHz). The U-NII-5 sub-band is 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. The U-NII-7 sub-band is not subject to DFS rules, but it has a lower maximum transmit power limit than the U-NII-5 sub-band.
• The Wi-Fi devices that operate in the 6 GHz band are called 6E devices, which stands for Extended Spectrum. 6E devices must support 802.11ax technology, which is also known as Wi-Fi 6 or High Efficiency (HE). 802.11ax is a new standard that improves the performance and efficiency of Wi-Fi networks by using features such as OFDMA (Orthogonal Frequency Division Multiple Access), MU-MIMO (Multi-User Multiple Input Multiple Output), BSS Coloring, TWT (Target Wake Time), and HE PHY and MAC enhancements.
• The 6E devices that operate in the 6 GHz band must also support WPA3 security, which is a new security protocol that replaces WPA2 and provides stronger encryption and authentication for Wi-Fi networks. WPA3 has two modes: WPA3-Personal and WPA3-Enterprise. WPA3-Personal uses SAE as its authentication method, which requires a passphrase to establish a secure connection between two devices. WPA3-Enterprise uses EAP (Extensible Authentication Protocol) as its authentication method, which requires a certificate or a credential to authenticate with a server.

Therefore, SAE is required when operating 802.11ax APs in the 6 GHz band using passphrase-based authentication because it is part of WPA3-Personal security, which is mandatory for 6E devices in this band. References: , Chapter 3, page 120; , Section 3.2

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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.

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.

An IBSS is used instead of a BSS is a network configuration that would result in multiple stations broadcasting Beacon frames with the same BSSID but with different source addresses. An IBSS (Independent Basic Service Set) is a type of WLAN that does not use an AP but rather allows stations to communicate directly with each other in a peer-to-peer manner. An IBSS is also known as an ad-hoc network or a peer-to-peer network. In an IBSS, each station generates its own Beacon frames to announce its presence and capabilities to other stations within range. The Beacon frames have the same BSSID, which is randomly generated by one of the stations when creating the IBSS, but they have different source addresses, which are the MAC addresses of each station’s radio interface. The BSSID is used to identify the IBSS and prevent stations from joining other IBSSs with different BSSIDs. References: , Chapter 1, page 25; , Section 1.1

In the 802.11 wireless networking protocols, when a client station sends a broadcast probe request frame with a wildcard SSID (Service Set Identifier), it is essentially asking for any nearby access points (APs) to identify themselves. The way APs respond to such a probe request is governed by standard 802.11 behavior, which includes:

• Probe Request Handling: Upon receiving a broadcast probe request, each AP that can serve the client prepares a probe response. The response includes information about the AP, such as its SSID, supported data rates, and other capabilities.
• Contention-Based Mechanism: Wireless networks use a contention-based mechanism (CSMA/CA - Carrier Sense Multiple Access with Collision Avoidance) for medium access. Each AP must wait for a clear channel and win the contention process before it can send its probe response.
• Independent Responses: Each AP operates independently in responding to the probe request. There is no coordination between APs to decide which one responds first or at all, leading to multiple APs sending probe responses, each after winning the contention for the medium.

Option A accurately reflects this process, indicating that each AP prepares and sends a probe response in turn, contingent upon winning the medium contention. The other options suggest mechanisms (such as coordination with a DHCP server or simultaneous responses after a Short Interframe Space (SIFS)) that do not align with standard 802.11 procedures for handling broadcast probe requests.

References:

• IEEE 802.11 Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications.
• CWNA Certified Wireless Network Administrator Official Study Guide: Exam PW0-105, by David D. Coleman and David A. Westcott.

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

 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

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

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.

The center frequency of channel 4 in the 2.4 GHz band is 2.427 GHz (2427 MHz). The center frequency of a channel is the midpoint of its frequency range, where the signal strength is highest and most concentrated. The center frequency of channel 1 in the 2.4 GHz band is 2.412 GHz (2412 MHz), as given in the question. The center frequency of each subsequent channel is obtained by adding 5 MHz to the previous channel’s center frequency, since the channels are spaced 5 MHz apart from each other in this band. Therefore, to find the center frequency of channel 4, we need to add 15 MHz (5 MHz x 3) to the center frequency of channel 1:

2.412 GHz + 0.015 GHz = 2.427 GHz

Alternatively, we can use a formula to calculate the center frequency of any channel in the 2.4 GHz band:

Center frequency (GHz) = 2.407 + (0.005 x Channel number)

Using this formula for channel 4, we get:

Center frequency (GHz) = 2.407 + (0.005 x 4)

Center frequency (GHz) = 2.407 + 0.02

Center frequency (GHz) = 2.427 References: 1, Chapter 3, page 85; 2, Section 3.2

DHCP (Dynamic Host Configuration Protocol) is a commonly used method to locate the controllers by the APs in a WLAN that is implemented using wireless controllers. DHCP is a protocol that allows a device to obtain an IP address and other network configuration parameters from a server. In a wireless controller scenario, the APs can use DHCP to request an IP address from a DHCP server, which can also provide the IP address or hostname of the wireless controller as an option in the DHCP response. This way, the APs can discover the wireless controller and establish a connection with it. Alternatively, the APs can also use other methods to locate the wireless controller, such as DNS (Domain Name System), broadcast or multicast discovery, or manual configuration. References: 1, Chapter 8, page 309; 2, Section 5.2

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: ExamCWNA-109], page 374; [CWNA: Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 364.

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 inthe 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 . References: [CWNA-109 Study Guide], Chapter 4: Radio Frequency Signal and Antenna Concepts, page 163; [CWNA-109Study Guide], Chapter 4: Radio Frequency Signal and Antenna Concepts, page 157.

An isotropic radiator is a theoretical point source of electromagnetic radiation that radiates equally in all directions. It has no physical dimensions and no preferred direction of radiation. It is used as a reference for antenna gain because it represents the ideal case of a perfect omnidirectional antenna12

Antenna gain is a measure of how well an antenna concentrates its radiated power in a certain direction. It is expressed in decibels (dB) relative to a reference antenna. Whenthe reference antenna is an isotropic radiator, the antenna gain is denoted by dBi, which stands for decibels relative to isotropic12

For example, an antenna with a gain of 3 dBi means that it radiates 3 dB more power in its main direction than an isotropic radiator would. Conversely, an antenna with a gain of -3 dBi means that it radiates 3 dB less power in its main direction than an isotropic radiator would12

Cellular/LTE/5G is the best method for implementing a network backhaul for communications across the Internet in a remote area that is affected by a natural disaster. This is because cellular/LTE/5G networks are wireless and do not depend on physical infrastructure that may be damaged or unavailable in such scenarios. Cellular/LTE/5G networks also offer high-speed data transmission and wide coverage area, which are essential for emergency response operations. 802.11 bridging to the response team headquarters is not feasible because it requires line-of-sight and has limited range. Turning up the output power of the WLAN at the response team headquarters is not effective because it may cause interference and does not guarantee reliable connectivity. Temporary wired DSL is not practical because it requires installing cables and equipment that may not be available or accessible in a remote area. References: CWNA-109 Study Guide, Chapter 7: Wireless LAN Topologies, page 2031

Shared Key Authentication is a security solution that was defined in the original 802.11 standard as an alternative to Open System Authentication, which does not provide any security at all. Shared Key Authentication uses WEP (Wired Equivalent Privacy) to encrypt and authenticate data frames between the client station and the AP. However, WEP has been proven to be extremely vulnerable to various attacks that can easily crack the encryption key and compromise the network security. Therefore, Shared Key Authentication is deprecated in the 802.11 standard and should never be used in any modern WLAN deployment . References: [CWNA-109 Study Guide], Chapter 10: Wireless LAN Security, page 401; [CWNA-109Study Guide], Chapter 10: Wireless LAN Security, page 391; [Wikipedia], Wired Equivalent Privacy.

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

The device in the bridge implementation that acts as the 802.1X Authenticator is the root bridge. The root bridge is the bridge that connects to the wired network and acts as the central point for all other bridges in the point-to-multipoint topology. The root bridge authenticates the non-root bridges using 802.1X/EAP and forwards their authentication requests to the RADIUS server. The non-root bridges act as the 802.1X Supplicants and use EAP methods such as EAP-TLS or EAP-PEAP to authenticate with the root bridge. References: [CWNP Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 459; [Cisco Aironet Wireless Bridges FAQ], question 29.

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.

An IEEE 802.11 amendment is a proposed change or addition to the existing 802.11 standard, which defines the specifications and protocols for wireless LANs. An amendment goes through several stages of development, such as draft, sponsor ballot, and final approval, before it is ratified by the IEEE Standards Association and becomes part of the standard. Until then, it has no official impact on the standard, although some vendors may release products based on draft amendments to gain a competitive edge or to influence the final outcome of the amendment . References: [CWNA-109 Study Guide], Chapter 1: Overview of Wireless Standards, Organizations, and Fundamentals, page 25; [CWNA-109Study Guide], Chapter 1: Overview of Wireless Standards, Organizations, and Fundamentals, page 23; [IEEE website], IEEE-SA Standards Development Process.

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

The BSSID (Basic Service Set Identifier) is typically mapped to an AP’s MAC address if a single BSS is implemented. The BSSID is a unique identifier that distinguishes one BSS from another within the same RF medium. It is usually derived from the MAC address of the AP’s radio interface, but it can also be manually configured or randomly generated by some vendors. The BSSID is used by client stations to associate with an AP and to send and receive frames within a BSS. References: , Chapter 1, page 24; , Section 1.2

Granting access to specific network services or resources according to a user profile describes the authorization component of a AAA implementation. AAA stands for Authentication, Authorization, and Accounting, which are three functions that are used to control and monitor access to network resources and services. Authentication is the process of verifying that a user is who he says he is, by using credentials such as username, password, certificate, token, or biometric data. Authorization is the process of granting access to specific network services or resources according to a user profile, which defines the user’s role, privileges, and permissions. Accounting is the process of recording and reporting the usage of network services or resources by a user, such as the duration, volume, type, and location of the access. AAA can be implemented by using different protocols andservers, such as RADIUS, TACACS+, LDAP, Kerberos, or Active Directory. References: 1, Chapter 11, page 449; 2, Section 7.1

In wireless communication, several factors influence the effective reception of RF signals, including the receiving station's radio sensitivity, the transmitting station's output power, and free space path loss. However, the receiving station's output power does not influence the distance at which an RF signal can be effectively received. The key factors that impact signal reception distance are:

• Receiving Station's Radio Sensitivity: This refers to the lowest signal strength at which the receiver can process a signal with an acceptableerror rate. Higher sensitivity allows for better reception at greater distances.
• Transmitting Station's Output Power: This is the power with which a transmitter sends out a signal. Higher output power can extend the range of transmission, making it easier for distant receivers to detect the signal.
• Free Space Path Loss (FSPL): FSPL represents the attenuation of radio energy as it travels through free space. It increases with distance and frequency, reducing the signal strength as the distance from the transmitter increases.

The output power of the receiving station is related to how strong a signal it sends out, not how well it can receive or process incoming signals. Therefore, it does not affect the reception distance of incoming RF signals.

References:

• CWNA Certified Wireless Network Administrator Official Study Guide: Exam PW0-105, by David D. Coleman and David A. Westcott.
• RF fundamentals and RF design considerations in wireless communication systems.

A common feature of MDM solutions that can be used to protect enterprise data on mobile devices is containerization. Containerization is a technique that creates a separate and secure environment on the mobile device where enterprise data and applications are stored and accessed. Containerization isolates the enterprise data from the personal data and prevents unauthorized access, leakage, or loss of sensitive information. Containerization can also enforce security policies, encryption, authentication, and remote wipe on the enterprise data and applications. Over-the-air registration, onboarding, and self-registration are features of MDM solutions that facilitate the enrollment and management of mobile devices, but they do not directly protect enterprise data on mobile devices. References: [CWNP Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 336; [CWNA: Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 326.

 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.