CWNP CWDP-305 - Certified Wireless Design Professional

The use of 80 MHz channel widths reduces the number of available non-overlapping channels in the 5 GHz band, increasing the likelihood of co-channel interference (CCI) and reducing frequency reuse. Although wider channels provide higher theoretical throughput, they are inappropriate in dense or high-concurrency environments due to overlap and contention.

According to CWDP-305, All-Wireless-Office (AWO) environments that rely entirely on WLAN for application delivery should be optimized for reliability and minimal interference. A channel plan using 20 MHz widths allows for better AP placement, isolation of frequencies, and greater spatial reuse, directly improving latency-sensitive application performance such as real-time communications or database access.

Changing the channel width to 20 MHz across the APs restores the integrity of the channel reuse plan and aligns with the original design, preventing interference that may degrade application performance.

Comprehensive and Detailed Explanation:

RF fingerprinting is a method used in WLANs to determine the location of a device by comparing the current signal characteristics (like signal strength and quality) to a pre-recorded database of signal profiles (fingerprints) taken at various locations. This technique allows for accurate indoor positioning without relying solely on signal strength calculations.

Option A:Inverse cube law is not typically used in WLAN location algorithms.

Option B:Free Space Path Loss (FSPL) calculations are more theoretical and less effective in complex indoor environments.

Option D:Clause 16 of the 802.11 standard pertains to mesh networking, not location algorithms.

The Project Charter is a foundational document in the WLAN design process. It formally authorizes the project, detailing the objectives, scope, key stakeholders, and providing the project manager with the authority to allocate resources and begin project activities. This document ensures that all parties have a clear understanding of the project's goals and boundaries from the outset.

In contrast:

The Bill of Materials (BoM) lists the hardware and software components required for the project but does not define the project's objectives or scope.

The Work Breakdown Structure (WBS) breaks down the project's deliverables into manageable sections but is developed after the project has been authorized.

The Budget outlines the financial resources allocated for the project but does not encompass the project's objectives or stakeholder information.

In the context of High-Level Design (HLD) documents within wireless network design, the primary audiences typically include operations teams, designers, and engineering personnel. These stakeholders are directly involved in the planning, implementation, and maintenance of the network infrastructure.

Executives, while important decision-makers, are not the primary audience for HLDs. Instead, they are more likely to engage with executive summaries or business case documents that highlight the strategic and financial implications of the network design, rather than the technical specifics detailed in HLDs.

Comprehensive and Detailed Explanation:

IEEE 802.3at, also known as PoE+, provides up to 25.5 watts of power per port. To support 6 access points requiring PoE+ power:

25.5 W/AP × 6 APs = 153 W

Considering some overhead for power loss and future scalability, a minimum PoE budget of 180 W is recommended to ensure reliable operation.

In WLAN design software, defining different “requirement areas” allows the designer to assign distinct RF and performance requirements to different parts of the floor plan. For instance, a voice-critical conference room may require –67 dBm minimum signal strength and a specific SNR, whereas a storage area might only require basic coverage.

From CWDP-305:

“Requirement areas allow WLAN designers to set different RF performance targets such as minimum signal strength, SNR, and data rate for specific parts of the deployment area. This enables tailored design strategies.”

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

Site survey adapters are often specialized devices with enhanced sensitivity and are calibrated for accurate measurements. In contrast, standard client devices may have varying hardware and driver configurations, leading to differences in RSSI readings. Therefore, it's common to observe discrepancies between survey results and actual client experiences. This emphasizes the importance of considering client device capabilities during WLAN design and validation.

When working in elevated environments, such as installing APs on ceilings higher than standard heights (e.g., warehouse or industrial sites), safety becomes a critical priority. According to the CWDP-305 Study Guide, proper personal protective equipment (PPE) is essential and typically includes a hardhat to protect from falling objects, a high-visibility vest to ensure visibility among other workers or moving machinery, and a body belt or harness when working at height. These safety requirements are commonly enforced by OSHA and are also discussed in wireless site survey preparation sections.

The IEEE 802.11-2016 standard specifies two methods for Fast BSS Transition (FT) to facilitate fast and secure roaming:mrn-cciew

Over-the-Air (OTA):The client communicates directly with the target AP to perform the authentication exchange during roaming.

Over-the-Distribution System (Over-the-DS):The client communicates with the current AP, which then communicates with the target AP over the distribution system to perform the authentication exchange.

These methods are designed to reduce the time required for re-authentication during roaming, ensuring minimal disruption to ongoing sessions.

The CWDP-305 Official Study and Reference Guide states:

"802.11r defines two methods for fast BSS transition: Over-the-Air and Over-the-DS, both aimed at reducing latency during client roaming."

802.11 admission control mechanisms are employed to manage and regulate the bandwidth resources available in a WLAN.By controlling the admission of traffic into the network, these mechanisms ensure that high-priority traffic, such as voice or video, receives the necessary resources for optimal performance.Admission control settings are configured separately for each Access Category (AC), allowing granular control over different types of traffic.