CWDP-305 Exam Dumps - Certified Wireless Design Professional

In the 2.4 GHz band, there are only three non-overlapping channels (1, 6, 11). Overuse of radios on the same or overlapping channels results in excessive co-channel interference (CCI), leading to contention and degraded throughput. The CWDP-305 Study Guide advises minimizing the number of active radios in the 2.4 GHz band in dense environments.

Turning off 2.4 GHz radios on some APs is the recommended action to reduce CCI without introducing adjacent-channel interference (ACI), which would occur if you used overlapping channels like 3, 4, or 8. This adjustment retains channel reuse efficiency and supports low-density legacy devices. It’s especially relevant in designs that primarily target 5 GHz or 6 GHz but include 2.4 GHz for backward compatibility.

In high-density environments like stadiums and convention centers, the presence of large crowds significantly impacts Wi-Fi signal propagation.Human bodies, composed mostly of water, absorb and attenuate radio frequency (RF) signals, especially in the 2.4 GHz and 5 GHz bands commonly used by Wi-Fi.This absorption leads to reduced signal strength and potential connectivity issues during events when the venue is filled with people.

Designing a WLAN for such environments requires careful consideration of crowd density and its impact on RF signals.Strategies may include increasing the number of access points (APs), using directional antennas to focus coverage, and conducting site surveys during events to assess real-world performance.

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.

WPA/WPA2-Enterprise provides enhanced security features suitable for enterprise environments, such as per-user authentication and dynamic encryption keys. However, these benefits come with certain drawbacks not present in WPA/WPA2-Personal:

Additional Infrastructure Requirements:WPA/WPA2-Enterprise typically requires a RADIUS server to handle authentication, which adds complexity and cost to the network infrastructure.

Increased Administrative Overhead:Configuring and maintaining WPA/WPA2-Enterprise involves managing user credentials, certificates, and RADIUS server settings, which demands more administrative effort compared to the simpler pre-shared key setup of WPA/WPA2-Personal.

It's important to note that WPA/WPA2-Enterprise does support the use of usernames and passwords for client authentication and provides mechanisms for per-user authorization and access control. While X.509 certificates are commonly used for server authentication in WPA/WPA2-Enterprise, they are not strictly required in all configurations.

When the WLAN controller and APs reside on different subnets, a router is required to facilitate communication between them. The router enables Layer 3 routing, allowing the APs to discover and communicate with the controller across subnet boundaries.

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:

Increasing capacity in a coverage-based wireless network involves optimizing the network to handle more clients and traffic efficiently. The recommended techniques include:

A. Maximize airtime usage by disabling lower data rates:Disabling lower data rates (e.g., 1 Mbps, 2 Mbps) reduces the time the medium is occupied by slower transmissions, thereby increasing overall network efficiency and capacity.

B. Add additional APs and use directional antennas:Deploying more access points (APs) with directional antennas helps in segmenting the coverage area, reducing co-channel interference, and increasing capacity by allowing more simultaneous transmissions in different directions.

D. Lower power on the access points and, after careful planning, add more APs:Reducing the transmit power of APs minimizes overlap and interference between cells. After careful planning, adding more APs ensures coverage continuity and increases capacity by distributing the load among more APs.

C. Turn up power on the access points:Increasing the transmit power can lead to excessive overlap between cells, causing interference and reducing overall network capacity. Therefore, this is not a recommended practice for increasing capacity.

Doubling the channel width increases the noise floor because the receiver is now listening over a wider range of frequencies, which can include more interference sources. This results in a decrease in SNR (Signal-to-Noise Ratio), which can negatively impact performance, especially in high-density deployments.

From CWDP-305:

“Channel bonding increases the bandwidth but also increases the amount of noise received. The increased noise can reduce the effective SNR and result in performance degradation, particularly in congested environments.”

— Reference: CWDP-305 Official Study and Reference Guide, Chapter on ProtocolandSpectrum Analysis