CWNP CWDP-305 - Certified Wireless Design Professional

Comprehensive and Detailed Explanation:

Mounting APs above the ceiling can significantly degrade WLAN performance due to signal attenuation caused by ceiling materials and obstructions. If aesthetic requirements were not communicated during the initial requirements gathering, the current deployment does not align with the documented design specifications. The appropriate course of action is to inform the stakeholder that the WLAN performance requirements may not be met under the current installation and that a new design process is necessary to address the aesthetic constraints while ensuring optimal performance.

Comprehensive and Detailed Explanation:

An incorrect Frame Check Sequence (FCS) indicates that the frame was corrupted during transmission. This corruption can be due to various factors, but in the context of a WLAN, common causes include multipath interference and excessive collisions. Multipath occurs when RF signals reflect off surfaces and arrive at the receiver at different times, causing interference. Excessive collisions can happen in environments with high device density or overlapping coverage areas, leading to degraded performance.

Understanding both the physical layout and logical configuration of the network is critical. The two most helpful documents for that are:

Blueprints:Provide the architectural layout of the facility, including walls, materials, and structural elements that affect RF propagation.

Network Closet Locations:Identify where networking equipment such as switches and patch panels are located for physical cabling and AP backhaul planning.

From CWDP-305:

“Accurate blueprints and physical infrastructure documentation, such as IDF/MDF locations, are essential for physical and logical WLAN planning.”

— Reference: CWDP-305 Official Study and Reference Guide, Chapter on Wireless Design Process

Upgrading access points (APs) from 802.11n to 802.11ac can offer higher throughput and improved performance. However, to realize these benefits, client devices must also support the newer standard. If the clients remain on 802.11n, they cannot take advantage of 802.11ac features such as wider channels, higher modulation schemes, and beamforming.

Therefore, the most likely reason for the unchanged throughput is that the clients were not upgraded to support 802.11ac.

Comprehensive and Detailed Explanation:

The "Network Card Simul-ation" feature in site survey software allows the simul-ation of RF data as if it were received by a specific client device.This is particularly useful for assessing uplink performance and understanding how different client devices, with varying antenna gains and sensitivities, would perform in the surveyed environment.By simulating different client types, network designers can ensure that the WLAN design accommodates the performance requirements of all intended client devices.

When using predictive design tools for WLAN planning, it's crucial to calibrate the floor plan to ensure accurate distance measurements. This involves setting the scale of the imported floor plan so that the tool can accurately simulate RF propagation and coverage.

The CWDP-305 Official Study and Reference Guide states:

"Before placing APs and other elements, calibrate the floor plan to ensure that distances and areas are accurately represented, which is essential for precise predictive modeling."

Comprehensive and Detailed Explanation:

In wired networks, VLANs effectively segment traffic into separate broadcast domains, isolating traffic between different VLANs. However, in wireless networks, while VLANs are used to assign different SSIDs to different VLANs, the wireless medium is inherently shared. This means that, despite VLAN assignments, all wireless traffic is transmitted over the same RF medium, and clients can still hear all transmissions. Therefore, wireless VLANs do not always provide the same level of traffic segmentation as wired VLANs.

In a Single Channel Architecture (SCA), all access points (APs) operate on the same channel and share a virtual Basic Service Set Identifier (BSSID).The wireless controller manages client associations by directing the client to the AP with the strongest Received Signal Strength Indicator (RSSI), ensuring optimal connectivity.

The CWDP-305 Official Study and Reference Guide explains:

"Using a SCA means that all APs will be using the same channel in a given layer. How is the AP with which the client associates determined? C. All APs share a virtual BSSID. A controller will tell the closest AP to the client to communicate with it, since it has a greater RSSI from the client."

Comprehensive and Detailed Explanation:

Enabling the "Validate server certificate" option is a critical security measure when configuring Extensible Authentication Protocol (EAP) types, such as EAP-TLS or PEAP. This setting ensures that the client verifies the authenticity of the RADIUS server's certificate during the authentication process, preventing man-in-the-middle attacks. By validating the server certificate, clients can confirm they are connecting to a legitimate network, thereby maintaining the integrity and security of the WLAN.

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In the 5 GHz band, certain channels like 144 are not universally supported across all devices, especially older 802.11n clients. If the AP is operating on channel 144, and the client's regulatory domain or hardware does not support this channel, the SSID will not be visible to the client.

The CWDP-305 Official Study and Reference Guide notes:

"Client devices may not support all channels in the 5 GHz band, depending on their regulatory domain and hardware capabilities. Channel 144, for example, is not supported by all 802.11n clients."