CWNP CWDP-305 - Certified Wireless Design Professional

A Wireless Intrusion Prevention System (WIPS) is a network security solution that monitors wireless LANs for unauthorized or malicious activity and provides real-time or automated responses. WIPS can perform a wide array of functions as outlined below:

A. Distributed protocol analysis:

WIPS sensors continuously scan wireless traffic and analyze frames to detect anomalies or policy violations in real time.

C. Performance monitoring and response:

WIPS can identify degradation in WLAN performance due to interference, misconfiguration, or rogue activity and alert administrators or take corrective action.

D. Data forensics and analysis:

WIPS platforms often include historical logging and reporting features that allow administrators to review past events and understand the timeline and impact of wireless threats.

E. Automated threat mitigation:

WIPS can automatically respond to threats by sending deauthentication frames, blocking MAC addresses, or disabling ports to mitigate rogue devices or attacks.

Note:

B. Client access to the distribution system is not a function of WIPS; it refers to client functionality in a WLAN, not a security service offered by WIPS.

“A WIPS performs functions such as rogue detection and mitigation, threat classification, forensic logging, and real-time protocol analysis. It can provide both historical analytics and proactive security enforcement.”

— CWDP-305 Study Guide, Chapter on Post-Design ValidationandTroubleshooting

Comprehensive and Detailed Explanation:

For Voice over IP (VoIP) over WLAN, seamless roaming is critical to maintain call quality. To achieve this:

D.Ensuring that at least two access points (APs) are visible with adequate signal strength from any location allows client devices to roam between APs without dropping the connection. This overlap facilitates smooth handoffs and maintains call continuity.

A.While measuring cell overlap is useful, the key is to design the network to provide the necessary overlap, not just measure it.

B.Increasing output power can lead to larger cells but may cause interference and reduce the number of available channels, which is counterproductive in dense environments.

C.Higher gain antennas focus the signal, which may not provide the desired omnidirectional coverage needed for consistent overlap.

Even when skipping a full pre-design site survey, performing a spectrum analysis walkthrough is considered a best practice. This is because spectrum analysis provides insights into non-Wi-Fi interference sources, such as microwave ovens, Bluetooth devices, cordless phones, and other RF-emitting equipment that may affect WLAN performance.

From CWDP-305:

“A spectrum analysis walkthrough of the facility, even in the absence of a full site survey, can reveal sources of interference that would otherwise go undetected. This step is highly recommended to validate the RF environment.”

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

Defining wall materials (e.g., drywall, brick, concrete) in WLAN design software is essential for accurate RF modeling. Different materials attenuate RF signals to varying degrees, and propagation models account for these losses to calculate realistic signal coverage.

From CWDP-305:

“Accurate modeling of RF signal behavior requires defining wall and obstacle materials to account for signal attenuation and reflections. This improves the accuracy of predictive design tools.”

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

Comprehensive and Detailed Explanation:

When discrepancies are found between the physical environment and the CAD drawings during a site survey, it's crucial to update the documentation to reflect the current state accurately. Redrawing the portions of the map that have changed ensures that the design and subsequent deployment are based on accurate information, leading to a more reliable and efficient wireless network.

Jitter and latency are two important metrics for measuring the quality and performance of wireless networks, especially for real-time applications such as voice and video. Latency is the average time taken for a data packet to reach the destination, while network jitter is the irregularity in latency. When the latency is consistently high, it can mean a slow but stable connection. On the other hand, a high jitter means there may be sporadic disruptions or delays in the transmission, which can affect the quality of service and user experience. Jitter is caused by various factors, such as network congestion, interference, routing changes, hardware issues, or packet prioritization. Jitter can be measured by calculating the difference between the latency of two consecutive packets, or by using the standard deviation of the latency of a sample of packets. Jitter can be reduced by using Quality of Service (QoS) mechanisms, such as traffic shaping, queuing, or scheduling, which can prioritize the packets based on their importance and sensitivity to delay. Jitter can also be mitigated by using jitter buffers, which can store the incoming packets and smooth out the variations in latency before delivering them to the application. References: CWNP, CWDP Certified Wireless Design Professional Official Study Guide, Network Jitter - Common Causes and Best Solutions, Network Jitter vs Latency: What’s the Difference and Why Does It Matter, Jitter vs Latency - What’s The Difference and Why it Matters

In WLAN deployments, each SSID is typically mapped to a unique VLAN. This allows logical separation of traffic, enabling different security policies, QoS settings, and routing for different user groups or services.

From CWDP-305:

“Each SSID in a WLAN is usually mapped to a different VLAN on the wired infrastructure. This allows for segregation of traffic, application of different network policies, and enhanced security enforcement.”

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

In a bandpass filter, the ripple refers to the variation in insertion loss within the passband.If the maximum in-band loss is 1.5 dB and the ripple is 0.4 dB, the minimum in-band loss can be calculated by subtracting the ripple from the maximum loss:blog.knowlescapacitors.com

1.5 dB (maximum loss) - 0.4 dB (ripple) = 1.1 dB (minimum loss)

Therefore, the minimum in-band loss is 1.1 dB.

IEEE 802.3at (PoE+) provides up to 30 watts of power per port. To determine how many devices can be supported with a total budget of 740 W:

740 W ÷ 30 W per device = 24.67

However, due to real-world power overheads and cable losses, it's safe to estimate each device may draw up to ~25–30 W. Most vendors recommend a planning budget of around 25–28 W per 802.3at device.

Safe calculation using full 30 W:

740 ÷ 30 = 24.6 → you could theoretically power 24, but for guaranteed power availability considering margin, most designs plan for:

740 ÷ 40 = 18.5 → about 18 devices conservatively

Answer: 18 devices can certainly be powered.

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

Software-defined radios (SDRs) offer flexibility in RF operation. In dual-band APs, an SDR can be programmed to operate on either 2.4 GHz or 5 GHz, allowing dynamic optimization of the spectrum based on demand and interference.

From CWDP-305:

“Software-defined radios can be configured to operate in either band, allowing administrators to shift coverage based on band congestion or capacity requirements.”

This flexibility helps address issues in high-density deployments or when minimizing interference is critical.

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