CWNP CWNA-109 Practice Test Questions, Exam Dumps

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CWNA-109 CWNP Practice Test Questions and Exam Dumps

Question No 1:

You administer a small WLAN with nine access points. As a small business, you do not run a RADIUS server and use WPA2-Personal for security and the APs are in autonomous mode. Recently, you changed the passphrase for WPA2-Personal in all APs and clients. Several users are now reporting the inability to connect to the network at times and it is constrained to one area of the building and those clients work properly elsewhere. When using a WLAN scanner, you see that the AP covering that area is online and has a strong signal. No other changes have been made to the environment and all access points are the same model.

What is the likely problem?

A. The AP that primarily covers the problem area is improperly configured
B. The clients are improperly configured
C. The AP that primarily covers the problem area has failed
D. The clients have failed network adapters

Answer: A

Explanation:

In a wireless LAN (WLAN) environment with multiple access points operating in autonomous mode and secured using WPA2-Personal, each access point must be individually configured, including settings like the SSID and passphrase. Unlike controller-based deployments, autonomous access points do not synchronize configurations automatically. Therefore, any configuration changes—such as updating a passphrase—must be made manually on each AP.

In this scenario, the administrator recently changed the WPA2-Personal passphrase across all APs and client devices. The issue is now isolated to one specific area of the building, and clients experience connectivity problems only in that area. They work normally in other areas. A WLAN scanner confirms that the access point covering the problematic area is online and broadcasting with a strong signal. This eliminates hardware failure or signal issues as probable causes.

Option A, which suggests that the AP is improperly configured, is the most likely explanation. Since all APs are managed independently and the change involved updating the WPA2-Personal passphrase, it's very plausible that the administrator mistakenly failed to update the passphrase on one access point. If the passphrase on that AP does not match the passphrase configured on the client devices, authentication will fail—even though the signal is strong and the AP is visible. The symptoms described (clients unable to connect in one area but working elsewhere) are consistent with this kind of misconfiguration.

Option B, that the clients are improperly configured, is unlikely because the clients function properly in other areas of the building. If the issue were client-side (such as an incorrect passphrase or network profile), the problem would be consistent across all locations, not just in one zone.

Option C, that the AP has failed, is not supported by the evidence. The WLAN scanner detects the AP as online with a strong signal. A hardware failure would typically render the AP undiscoverable, not simply cause connection rejections.

Option D, suggesting failed network adapters, is also unlikely. Since multiple clients experience the problem and their adapters work normally in other areas, it's improbable that simultaneous hardware failure is the issue.

In conclusion, given that the network functions correctly in all areas except one and that the only recent change was a security passphrase update, the most plausible explanation is that the AP in that problematic area was either skipped or misconfigured during the update process. Thus, the access point is broadcasting but rejecting client connections due to a mismatch in WPA2-Personal credentials. This aligns best with Option A: the AP that primarily covers the problem area is improperly configured.

Question No 2:

What is required when operating 802.11ax APs in the 6 GHz band using passphrase-based authentication?

A. VHT PHY
B. CCMP
C. SAE
D. HT PHY

Answer: C

Explanation:

When operating 802.11ax access points (APs) in the 6 GHz band using passphrase-based authentication, the correct protocol requirement is SAE (Simultaneous Authentication of Equals).

SAE is the authentication mechanism used in Wi-Fi 6 (802.11ax) for passphrase-based authentication, especially when operating in the 6 GHz band. SAE is a robust, secure, and resistant-to-offline-dictionary attacks protocol introduced with WPA3, and it replaces the older Pre-Shared Key (PSK) authentication method used in WPA2. The use of SAE ensures secure and resilient password authentication, which is especially critical in the 6 GHz band, a newly allocated frequency that operates under the Wi-Fi 6 and WPA3 standards.

Here’s why the other options are not correct:

A. VHT PHY: The VHT (Very High Throughput) PHY is associated with 802.11ac (Wi-Fi 5), not specifically with Wi-Fi 6 or the 6 GHz band. 802.11ax (Wi-Fi 6) APs in the 6 GHz band would primarily use HE PHY (High Efficiency PHY), which is designed for higher efficiency and capacity, as well as better performance in the new spectrum. So, VHT PHY is not the right answer for the 6 GHz band and passphrase-based authentication in the context of 802.11ax.
B. CCMP: CCMP (Counter Mode Cipher Block Chaining Message Authentication Code Protocol) is a security protocol used for data encryption in WPA2 and WPA3. While it’s important for the overall security of Wi-Fi networks, it does not directly relate to the authentication method required in 802.11ax networks operating in the 6 GHz band. The use of SAE for authentication is the key requirement for passphrase-based authentication in this context, not CCMP.
D. HT PHY: HT PHY (High Throughput PHY) is used in 802.11n (Wi-Fi 4) and supports the 2.4 GHz and 5 GHz bands. It is not associated with the 6 GHz band or the latest 802.11ax standards, which use the HE PHY instead.

In conclusion, SAE (Simultaneous Authentication of Equals) is the required protocol when using passphrase-based authentication in the 6 GHz band with 802.11ax access points, making C the correct answer.

Question No 3:

What can be determined as certainly true about an AP advertised as a tri-band, 4x4:4, Wi-Fi 6, 802.11ax AP?

A. It supports four channels in 2.4 GHz and four channels in 5 GHz
B. It has four radio chains
C. It supports UL-MU-MIMO
D. It uses a modified OpenWRT firmware

Answer: B

Explanation:

To accurately assess what can be determined about an access point (AP) based on its advertisement, we must first break down the terms used in the description.

Tri-band: This means the AP operates on three frequency bands. Typically, this would refer to:

2.4 GHz
5 GHz (often supporting two separate channels or frequency bands within this spectrum, such as 5 GHz-1 and 5 GHz-2)
A third band, which in modern Wi-Fi 6 (802.11ax) APs is often the 6 GHz band, but some tri-band APs can have two 5 GHz bands and one 2.4 GHz band.

4x4:4: This specification refers to the number of radio chains and spatial streams the AP can support:

4x4: This indicates the AP has four transmitters and four receivers, meaning it can handle four radio chains.
4: This refers to the number of spatial streams the AP can support in both transmitting and receiving directions. Each stream is a separate data path used for transmission, which improves overall throughput.

Wi-Fi 6, 802.11ax: Wi-Fi 6 (802.11ax) is the latest Wi-Fi standard, offering improvements such as higher speeds, better efficiency, and support for new technologies like MU-MIMO (Multi-User, Multiple Input, Multiple Output) and OFDMA (Orthogonal Frequency Division Multiple Access). MU-MIMO is particularly important because it allows the AP to serve multiple clients simultaneously.

Based on this information, let's examine the options:

A. It supports four channels in 2.4 GHz and four channels in 5 GHz:
While the AP might indeed support multiple channels in both the 2.4 GHz and 5 GHz bands, the number of channels in each band isn't guaranteed based on the description. Tri-band simply indicates three distinct bands (likely 2.4 GHz, 5 GHz, and 6 GHz or a second 5 GHz band), but it doesn't specify the number of channels per band. Therefore, this statement isn't certainly true based on the provided information.

B. It has four radio chains:
This is certainly true based on the 4x4 specification. "4x4" explicitly refers to four transmit and four receive radio chains, so this is directly supported by the description.

C. It supports UL-MU-MIMO:
Wi-Fi 6 (802.11ax) supports UL-MU-MIMO (Uplink Multi-User MIMO), but this capability is not guaranteed solely by the AP’s tri-band and 4x4:4 specs. While Wi-Fi 6 does enable UL-MU-MIMO, its actual support depends on the specific AP implementation. Therefore, while it's likely, it is not "certainly true" based on just the description provided.

D. It uses a modified OpenWRT firmware:
There is no information in the description that suggests the AP uses OpenWRT or any specific firmware. OpenWRT is a Linux-based open-source firmware commonly used for routers, but the description of the AP does not mention anything about its firmware. Thus, this statement cannot be determined as certainly true.

In conclusion, the only statement that can be determined as certainly true based on the provided advertisement is that the AP has four radio chains, as indicated by the 4x4 specification.

Question No 4:

What should be inspected to verify proper configuration when troubleshooting a controller-based AP that is unable to locate the controller, considering that DHCP is not used and the controller is located at 10.10.10.81/24 while the AP is on the 10.10.16.0/24 network?

A. TFTP
B. Controller hosts file
C. DNS
D. WINS

Answer: B

Explanation:

When troubleshooting a controller-based access point (AP) that cannot locate its controller, it is crucial to ensure that the AP can communicate with the controller and that it knows the correct IP address of the controller. Given that DHCP is not used and the AP is on a different subnet (10.10.16.0/24) than the controller (10.10.10.81/24), there are a few configuration checks to consider. The correct answer is to inspect the Controller hosts file.

Here’s why:

Controller hosts file (B): The hosts file on the AP or on the controller may be configured to map hostnames to IP addresses, especially in environments where DHCP is not used. If the AP cannot find the controller through broadcast methods (such as DHCP), it may rely on the controller's IP address being hardcoded or explicitly listed in the hosts file. Since the AP is on a different subnet (10.10.16.0/24) from the controller (10.10.10.81/24), the AP might need to know exactly where the controller is located through static IP configuration or by checking the hosts file on the AP or within the controller configuration. If there’s a misconfiguration or missing entry, the AP will be unable to locate the controller.
TFTP (A): While TFTP is often used for provisioning and configuration of network devices, it is not directly involved in the AP’s discovery of the controller. In this case, the AP is attempting to locate the controller and, without DHCP, needs a reliable method to resolve the controller’s IP address. TFTP might be used for transferring configuration files once the controller is located, but it does not play a significant role in the initial discovery process.
DNS (C): DNS could potentially be useful if the AP were attempting to locate the controller by hostname, but this is not a common setup for controller-based APs unless specifically configured. Given that the scenario specifies the absence of DHCP, it's more likely that the AP will rely on a statically configured IP or a manually configured hostname-to-IP mapping (via a hosts file) rather than relying on DNS for resolution.
WINS (D): WINS is a Microsoft technology for resolving NetBIOS names to IP addresses, but it is not typically used in modern networking environments, especially in the context of wireless LAN controllers and APs. The AP's primary concern here is the IP address of the controller, not NetBIOS names. WINS is therefore unlikely to be involved in this troubleshooting process.

In summary, the Controller hosts file is the most relevant component to inspect. It may contain a static IP address or hostname mapping that allows the AP to find the controller, and ensuring that this configuration is correct is crucial for successful communication between the AP and the controller.

Question No 5:

You are a small business wireless network consultant and provide WLAN services for various companies. You receive a call from one of your customers stating that their laptop computers suddenly started experiencing much slower data transfers while connected to the WLAN. This company is located in a multi-tenant office building and the WLAN was designed to support laptops, tablets, and mobile phones.

What could cause a sudden change in performance for the laptop computers?

A. A few of your customer's users have Bluetooth enabled wireless headsets.
B. A new tenant in the building has set their AP to the same RF channel that your customer is using.
C. The sky was not as cloudy that day as it typically is and the sun also radiates electromagnetic waves.
D. The antennas in the laptops have been repositioned.

Correct Answer: B

Explanation:

When troubleshooting WLAN performance issues, especially in a multi-tenant building, there are several common factors that could suddenly cause a degradation in network performance. Let’s break down each option and analyze its relevance to the described problem.

Option A: A few of your customer's users have Bluetooth-enabled wireless headsets.
Bluetooth operates in the 2.4 GHz frequency band, which overlaps with the Wi-Fi spectrum (especially for older Wi-Fi standards like 802.11b/g/n). However, Bluetooth typically operates in a frequency-hopping manner, which means it does not constantly occupy the same channel and typically wouldn’t cause sudden and significant performance degradation unless there is a high volume of Bluetooth devices actively transmitting. In most cases, Bluetooth interference would lead to slower data rates, but it’s less likely to be the primary cause of sudden and widespread issues like those described.
Option B: A new tenant in the building has set their AP to the same RF channel that your customer is using.
This is a very likely cause of the issue. In a multi-tenant building, if another tenant installs an access point (AP) that is set to the same RF channel as your customer's WLAN, channel interference can occur. Wi-Fi channels are typically 20 MHz wide, and when multiple APs are on the same or adjacent channels, their signals can interfere with each other. This results in slower data transfer speeds as the signals are garbled and the devices need to retransmit data. The interference from a neighboring AP could easily explain the sudden performance degradation your customer is experiencing.
Option C: The sky was not as cloudy that day as it typically is, and the sun also radiates electromagnetic waves.
This option is highly unlikely to be a contributing factor. While electromagnetic interference can come from natural sources, such as solar radiation, it’s extremely rare for atmospheric conditions like cloud cover or sunlight to suddenly cause WLAN performance issues. The influence of sunlight or cloud cover would generally have a negligible effect on WLAN performance unless the WLAN system is in an extremely unique environment, which is highly unlikely in an office building.
Option D: The antennas in the laptops have been repositioned.
While repositioning the antennas in the laptops could lead to performance degradation if the signal strength or quality is reduced, it’s unlikely that this change would suddenly affect the entire network. Antenna repositioning typically leads to gradual performance changes or reduced coverage but wouldn't likely cause a sudden performance drop for multiple users simultaneously. This issue would also be more localized to specific laptops, not affecting the entire WLAN.

In conclusion, the most probable cause for the sudden performance drop is interference from another tenant's AP using the same RF channel. This is a common issue in shared environments like multi-tenant office buildings and can cause significant channel congestion, which results in slower data transfers across the WLAN. Therefore, Option B is the best explanation.

Question No 6:

You administer a WLAN that offers a guest SSID of GUESTNWORK. Users connect to the GUESTNWORK SSID, but report that they cannot browse the Internet. The devices simply report no Internet connection.

What common problem causes this scenario?

A. NTP issues
B. SSL/TLS websites
C. TFTP issues
D. Captive portal issues

Answer: D

Explanation:

The scenario described points to a common issue with guest Wi-Fi networks that use a captive portal for user authentication or redirection. A captive portal is a web page that is typically displayed when a user first connects to a public or guest Wi-Fi network. This page usually requires users to accept terms of service, sign in, or input credentials before they are granted full access to the internet. In this case, users are connected to the guest SSID, but they cannot browse the internet, which suggests that the captive portal may not be functioning properly.

When a user connects to a network with a captive portal, the device will often attempt to load a page that prompts the user to log in or accept terms. If the captive portal is misconfigured or not working correctly, it can prevent the device from fully connecting to the internet. The common issue is that the portal is either not displaying or not redirecting properly, leading to users being unable to access any external websites, including the intended authentication or landing page.

Why other options are incorrect:

A. NTP issues: While Network Time Protocol (NTP) issues can cause problems with devices syncing time, this is unlikely to directly impact users' ability to access the internet on a guest network. NTP issues might affect the functioning of certain time-sensitive operations, but they wouldn’t typically block internet browsing unless they were causing a broader system failure related to security certificates or time-based authentication systems.
B. SSL/TLS websites: Problems with SSL/TLS websites could prevent secure browsing, but they would not explain why users cannot browse any website at all, especially if SSL/TLS issues were specific to certain websites. In this scenario, the problem appears to be with connectivity itself, rather than with specific types of websites.
C. TFTP issues: Trivial File Transfer Protocol (TFTP) is used for simple file transfers and is unrelated to general web browsing or internet access. TFTP issues would typically affect device configurations, not the ability to browse the internet.

In summary, captured portal issues are the most likely cause of users being unable to browse the internet after connecting to a guest SSID, especially when they are not being redirected to the necessary authentication page. Properly configuring or troubleshooting the captive portal should resolve this issue.

Question No 7:

As an RF wave propagates through space, the wave front experiences natural expansion that reduces its signal strength in any specific remote area.

What describes the rate at which this expansion happens?

A. Frontwave thinning theory
B. Ohm's law
C. Return loss or through loss
D. Inverse square law

Answer: D

Explanation:

The phenomenon described in the question, where an RF (radio frequency) wave propagates through space and experiences a reduction in signal strength due to expansion, is governed by the inverse square law. This law is a fundamental principle in physics and telecommunications that explains how the power of a signal decreases as it travels further from the source.

Inverse Square Law:
The inverse square law states that the intensity (or power) of a wave is inversely proportional to the square of the distance from the source. In the context of RF waves, as the wavefront expands spherically from the source, the power per unit area decreases because the wave is spread over a larger area. Specifically, if the distance from the source is doubled, the signal strength decreases by a factor of four (since 2² = 4). This reduction happens because the energy is distributed over a larger surface area, which results in a lower power density.

For example, in the case of an ideal radio wave radiating from an antenna, the power density (signal strength) at a distance r from the antenna can be calculated using the inverse square law as follows:

P(r)∝1r2P(r) \propto \frac{1}{r^2}P(r)∝r21

Where:

P(r)P(r)P(r) is the power at distance r,
rrr is the distance from the source,
The intensity decreases as the square of the distance from the source.

Thus, D. Inverse square law correctly describes the rate at which the RF wave expands and loses signal strength over distance.

Let’s look at the incorrect options for clarification:

A. Frontwave thinning theory: This is not a standard term in physics or telecommunications and does not accurately describe the propagation behavior of RF waves. It seems to be a made-up term rather than a well-established principle.
B. Ohm's law: Ohm's law is a fundamental electrical principle that relates voltage, current, and resistance in a circuit. It does not apply to the propagation of electromagnetic waves in space.
C. Return loss or through loss: These terms refer to losses that occur due to impedance mismatches (return loss) or signal attenuation through a medium (through loss), but they do not directly describe the natural expansion and reduction in signal strength as an RF wave propagates through space.

In summary, the inverse square law accurately describes how the signal strength of an RF wave decreases as it propagates away from the source, making D the correct answer.

Question No 8:

A client STA must choose the best AP for connectivity. As part of the evaluation, it must verify compatible data rates. What can the client STA use to verify that an AP supports the same data rates that it supports?

A. Probe request frames transmitted by other client STAs
B. Beacon frames transmitted by the AP
C. Authentication frames transmitted by the other client STAs
D. Data frames sent between the AP and current client STAs

Answer: B

Explanation:

In wireless networks, a client Station (STA) must select an Access Point (AP) that supports compatible data rates to ensure the best performance. One important factor for choosing the best AP is to verify the data rates that both the client STA and the AP support. The data rates of the AP can be determined by examining the beacon frames transmitted by the AP.

Beacon frames transmitted by the AP (B) contain vital information about the AP's capabilities, including the supported data rates, the type of wireless technology (e.g., 802.11a/b/g/n/ac/ax), and other network parameters like the SSID, encryption settings, and more. This makes beacon frames the most reliable and direct source of information for a client STA to determine if the AP supports the same data rates it can operate at. Beacon frames are broadcast regularly by the AP to announce its presence and capabilities.
Probe request frames transmitted by other client STAs (A) are used by clients to actively search for nearby APs, but these frames do not contain the data rate information of the AP. Rather, they are used for the client STA to query APs for information. Thus, the client STA would not use probe requests to determine the AP’s supported data rates.
Authentication frames transmitted by the other client STAs (C) involve the process of verifying the identity of the device, but they do not contain any information about the AP's data rates or its capabilities. Authentication frames are essential for establishing a connection but do not help in evaluating the AP's data rate support.
Data frames sent between the AP and current client STAs (D) represent the actual data transfer between the AP and a connected client but do not provide information about the AP's data rates or its supported rates for new client STAs. These frames are involved in communication but not in the AP discovery process regarding supported rates.

Thus, the beacon frames transmitted by the AP are the most useful for the client STA to determine if the AP supports compatible data rates.

Question No 9:

You support a WLAN using dual-band 802.11ac three stream access points. All access points have both the 2.4 GHz and 5 GHz radios enabled and use 40 MHz channels in 5 GHz and 20 MHz channels in 2.4 GHz with one of each radio operational. A manager is concerned about the fact that each access point is connected using a 1 Gbps Ethernet link.

He is concerned that the Ethernet link will not be able to handle the load from the wireless radios. What do you tell him?

A. His concern is invalid because the AP will compress all data before transmitting it onto the Ethernet link.
B. Due 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.
C. His concern is valid and the company should immediately plan to run a second 1 Gbps Ethernet link to each AP.
D. His concern is valid and the company should upgrade all Ethernet links to 10 Gbps immediately.

Correct Answer: B

Explanation:

In this scenario, the manager’s concern centers on whether the 1 Gbps Ethernet link will be able to handle the traffic generated by the dual-band 802.11ac access points, particularly given the 2.4 GHz and 5 GHz radios operating simultaneously. Let’s analyze the situation and why B is the most appropriate response.

A. His concern is invalid because the AP will compress all data before transmitting it onto the Ethernet link.
This option is incorrect because while compression can sometimes be used to reduce data sizes in specific scenarios, 802.11ac does not inherently rely on compression before transmitting data to the Ethernet link. The access point will forward data over the Ethernet link as it is transmitted from the wireless clients. In practice, there is no built-in guarantee that compression will significantly reduce the bandwidth required in this case, so it is not a reliable justification.
B. Due 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 correct. Even though dual-band radios are operating, the 802.11ac standard (especially when using 3 streams and 40 MHz channels in 5 GHz) can theoretically deliver high data rates. However, there are several factors to consider that limit the likelihood of the Ethernet link being saturated:

802.11ac is highly dependent on dynamic rates based on factors like signal quality, interference, and the capabilities of connected devices. The actual throughput will vary and is often lower than the maximum theoretical rates.
In practice, the wireless radios will typically not operate at maximum capacity all the time, and the overall network performance is often influenced by environmental factors, congestion, and the types of devices connected. This results in the wireless traffic being unlikely to consistently hit 1 Gbps or exceed it.
Even with multiple clients connected across both radios, the aggregate throughput will still be spread across multiple users, and this distribution generally prevents the 1 Gbps Ethernet link from becoming a bottleneck. Therefore, the 1 Gbps link should be adequate for typical usage in most enterprise environments.

C. His concern is valid and the company should immediately plan to run a second 1 Gbps Ethernet link to each AP.
This option is incorrect because, based on the analysis in B, there is no immediate need for a second 1 Gbps link. The wireless radios will likely not generate enough traffic to overwhelm the current 1 Gbps link, so adding another Ethernet link would not be necessary unless the network is operating under unusual or extreme conditions.
D. His concern is valid and the company should upgrade all Ethernet links to 10 Gbps immediately.
This option is incorrect because it is an overreaction. While upgrading to 10 Gbps might seem appealing for future-proofing, the 1 Gbps Ethernet link should be sufficient for the current setup, as wireless traffic is unlikely to exceed this capacity under normal circumstances. An upgrade to 10 Gbps would be an unnecessary expense without clear evidence that the network is regularly exceeding the 1 Gbps threshold.

In conclusion, B is the correct answer because it takes into account the dynamic nature of wireless networking, where factors like distance, interference, and device capabilities influence actual throughput. Under typical conditions, the 1 Gbps Ethernet link will be sufficient to handle the load from the dual-band 802.11ac access points.

Question No 10:

ABC Company is planning to install a new 802.11ac WLAN, but wants to upgrade its wired infrastructure first to provide the best user experience possible. ABC Company has hired you to perform the RF site survey. During the interview with the network manager, you are told that the new Ethernet edge switches will support VoIP phones and 802.11 access points, both using 802.3 PoE.

After hearing this information, what immediate concerns do you note?

A. The edge Ethernet switches should support Ether-channel to get the best results out of the network
B. VoIP phones and 802.11 access points should not be powered by the same edge switch due to distortion
C. If the switches are in optimal locations for VoIP phones, they are likely to be suboptimal locations for 802.11 APs
D. The power budget in the edge switches must be carefully planned and monitored based on the number of supported PoE devices

Correct answer: D

Explanation:

When installing a new wireless LAN (WLAN) and upgrading the wired infrastructure, there are several factors to consider in order to ensure optimal performance and a positive user experience. Specifically, the key concern here is the power requirements for devices that rely on Power over Ethernet (PoE), such as VoIP phones and 802.11 access points (APs).

A (Ether-channel support): While EtherChannel (also known as link aggregation) is useful for increasing bandwidth between switches and ensuring better redundancy, it is not an immediate concern for the scenario described. EtherChannel would be beneficial for handling increased traffic across multiple links, but the primary issue here is the power requirements for the PoE devices, not the network’s bandwidth. Hence, A is not the immediate concern.
B (VoIP phones and APs powered by the same switch): The idea that VoIP phones and 802.11 access points should not be powered by the same switch due to distortion is incorrect. VoIP phones and APs can indeed be powered by the same PoE-enabled switch without causing interference or distortion. Both devices typically operate on different channels and frequencies, and as long as the PoE budget is managed well, they can coexist on the same switch without issues. So, B is not the correct concern.
C (Switch locations for VoIP and APs): The placement of switches to optimize locations for VoIP phones and access points (APs) is important, but the main concern is not about location conflicts between these two devices. While AP placement is critical for WLAN performance, the issue here is more about the power availability rather than the physical location of switches. Therefore, C is a secondary consideration compared to power allocation and is not the most immediate concern.
D (Power budget in edge switches): The most immediate concern in this scenario is the power budget in the edge switches. Since both VoIP phones and APs will be powered by the same switches using 802.3 PoE, it is essential to carefully plan the PoE budget to ensure that there is enough power available for all devices. The total PoE power budget of a switch can be easily exceeded if too many devices are powered simultaneously, leading to a lack of power for some devices or performance degradation. Monitoring and planning the PoE budget based on the number of connected devices is critical to ensure that both VoIP phones and APs operate efficiently and without interruptions. Therefore, D is the most important concern here.

In summary, D is the correct answer because the PoE power budget is the primary factor that needs to be carefully planned and monitored to ensure that both VoIP phones and 802.11 APs can function properly without running into power limitations.