CWNP CWNA-109 Practice Test - Questions Answers, Page 12

The least expensive solution available for increasing throughput for these users without implementing configuration options that are not recommended is touse a 40 MHz channel on the 5 GHz radio. This solution can double the channel bandwidth and increase the data rates for the 5 GHz capable 802.11ac clients. Using a 40 MHz channel on the 5 GHz radio is also less likely to cause co-channel interference or overlap with other channels than using a 40 MHz channel on the 2.4 GHz radio, which has only three non-overlapping channels. Using a 160 MHz channel on the 5 GHz radio may provide even higher throughput, but it may also consume too much of the available spectrum and cause more interference with other devices or networks. Installing a second AP in the coverage area may also improve the throughput, but it may require additional costs and configuration.Reference:[CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 216; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 206.

The fact that is true regarding controllers and APs in a Split MAC architecture is thatan IP tunnel is established between the AP and controller for AP management and control functions. A Split MAC architecture is a WLAN architecture where some of the MAC layer functions are performed by the APs (such as encryption, decryption, and frame acknowledgement) and some are performed by the controllers (such as authentication, association, roaming, and QoS). To communicate with each other, the APs and controllers establish an IP tunnel that carries the management and control frames between them. The IP tunnel can use protocols such as Lightweight Access Point Protocol (LWAPP) or Control And Provisioning of Wireless Access Points (CAPWAP).Reference:[CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 372; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 362.

An access point is configured by a WLAN controller in the management plane of the three networking planes. The management plane is responsible for the configuration, administration, and monitoring of network devices, such as access points, switches, routers, and controllers. The WLAN controller communicates with the access point using a management protocol, such as CAPWAP or SNMP, to send configuration commands and receive status information. The control plane is responsible for the routing, switching, and forwarding of network traffic, such as data frames and control frames. The WLAN controller may also participate in the control plane by performing functions such as authentication, encryption, roaming, and load balancing. The security plane is responsible for the protection of network devices and data from unauthorized access, modification, or disclosure. The WLAN controller may also participate in the security plane by implementing features such as firewall, VPN, IDS/IPS, and WIPS. The data plane is responsible for the transmission and reception of user data, such as voice, video, or web traffic. The WLAN controller may or may not participate in the data plane depending on the architecture of the WLAN. In some cases, the access point forwards the user data directly to the wired network without involving the WLAN controller (distributed data forwarding). In other cases, the access point tunnels the user data to the WLAN controller before forwarding it to the wired network (centralized data forwarding).Reference:CWNA-109 Study Guide, Chapter 9: Wireless LAN Architecture, page 279

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

CCI is still a possibility in this network because the client devices connected to one of the channel 1 APs will transmit frames that reach the other channel 1 AP as well as clients connected to the other channel 1 AP. CCI stands for co-channel interference, which is a type of interference that occurs when two or more devices transmit on the same channel within range of each other. CCI reduces performance and capacity because it causes contention and collisions on the wireless medium, which leads to retransmissions and delays. CCI can be mitigated by increasing physical separation between devices using the same channel or by reducing transmit power levels to limit coverage area. In this scenario, three access points are used within a facility. One access point is on channel 11 and the other two are on channel 1. The two access points using channel 1 are on either side of the access point using channel 11 and sufficiently apart so that they do not interfere with each other when they transmit frames. However, this does not prevent CCI from occurring between their client devices that are connected on channel 1. For example, if a client device connected to one of the channel 1 APs sends a frame to another device on the wired network or on another wireless network (such as an Internet server or a VoIP phone), that frame will be heard by both channel 1 APs as well as any other client devices connected to either of them on channel 1. This will cause CCI because these devices will have to wait for the channel to be clear before they can transmit their own frames. The answer that CCI only occurs in the 5 GHz frequency band is incorrect; CCI can occur in any frequency band where devices use the same channel. The answer that channel 11 loops around and causes CCI with channel 1 is also incorrect; channel 11 does not loop around and it operates in a different frequency band than channel 1.Reference:CWNA-109 Study Guide, Chapter 5: Radio Frequency Signal and Antenna Concepts, page 147

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

A common feature of MDM solutions that can be used to protect enterprise data on mobile devices iscontainerization. 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.Reference:[CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 336; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 326.

What you should tell him is thatdue to 802.11 network operations and the dynamic rates used by devices on the network, the two radios will likely not exceed the 1 Gbps Ethernet link. This is because the actual throughput of an 802.11 network is much lower than the theoretical data rates due to factors such as overhead, contention, interference, retransmissions, and environmental conditions. Moreover, the data rates used by devices on the network vary depending on their distance, signal quality, capabilities, and configuration. Therefore, it is unlikely that both radios of the AP will simultaneously use the maximum data rates and saturate the 1 Gbps Ethernet link. Upgrading to a 10 Gbps Ethernet link or running a second 1 Gbps Ethernet link may be unnecessary and costly. Compressing all data before transmitting it onto the Ethernet link may introduce additional overhead and latency.Reference:[CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 227; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 217.

What should be inspected to verify proper configuration isDNS. 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.Reference:[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.