Free Practice Questions for CWNP CWDP-305 Exam

A coverage-based wireless network design focuses on providing signal coverage over a large area using fewer APs operating at higher power levels. This approach aims to ensure that the entire area has basic connectivity. However, it may not support high client densities or bandwidth-intensive applications effectively. In contrast, a capacity-based design would involve deploying more APs at lower power levels to handle a higher number of clients and provide better performance.

In the 5 GHz band, all Wi-Fi traffic (802.11a/n/ac/ax) uses OFDM or OFDMA modulation. If multiple APs use overlapping or identical channels, this results in Co-Channel Interference (CCI). Legacy technologies like HR/DSSS and ERP operate in 2.4 GHz and do not contribute to CCI in 5 GHz.

From CWDP-305:

“CCI occurs when multiple devices share the same channel. In 5 GHz, all compliant Wi-Fi traffic uses OFDM-based PHYs, so other nearby OFDM networks are a primary source of CCI.”

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

Comprehensive and Detailed Explanation:

In the "local MAC" variation of the centralized WLAN architecture, all MAC (Media Access Control) functions are performed by the Access Point (AP). A minimal subset of network control is offloaded to the WLAN controller, which also handles management and monitoring functions. This approach allows for more efficient processing at the edge of the network, reducing latency and improving performance.

Comprehensive and Detailed Explanation:

The IEEE 802.11 standard does not mandate a specific calibration accuracy for Received Signal Strength Indicator (RSSI) and Signal-to-Noise Ratio (SNR) reporting across client devices. RSSI values are relative and can vary between different hardware vendors, as each manufacturer may implement their own scale and measurement methods. This lack of standardization means that RSSI readings are not directly comparable across different devices. Therefore, there is no specific value to which clients are required to be calibrated for RSSI and SNR reporting.

DHCP Option 43 is utilized to provide vendor-specific information to DHCP clients. In WLAN deployments, particularly with lightweight access points (APs), Option 43 is used to convey the IP address of the Wireless LAN Controller (WLC) that the AP should join. The AP includes a Vendor Class Identifier (Option 60) in its DHCP Discover message, and the DHCP server responds with Option 43 containing the WLC's IP address. This mechanism facilitates the automatic discovery and association of APs with their respective controllers, streamlining network deployment and management.Cisco

Comprehensive and Detailed Explanation:

In voice over WLAN (VoWLAN) deployments, seamless roaming is critical to maintain call quality. As users move throughout the office, their devices must transition between access points without dropping the call or experiencing latency. Therefore, ensuring efficient and fast roaming capabilities is paramount in the design of a WLAN intended to support voice applications.

Conducting a post-deployment survey before all APs are installed—particularly in a multi-floor environment—may yield incomplete results. APs from other floors can influence coverage (due to bleed-through floors), roaming behavior, and channel planning, so the validation should ideally happen after full deployment.

From CWDP-305:

“In multi-floor environments, APs from upper and lower floors contribute to the RF landscape. Validation should wait until all APs are installed to evaluate the WLAN's full performance characteristics.”

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

Comprehensive and Detailed Explanation:

Push-to-Talk (PTT) VoWiFi phones often require multicast packet delivery support within the WLAN infrastructure. PTT communications are typically group-based, where the same voice message needs to be delivered simultaneously to multiple recipients. Multicast transmission is efficient for this purpose, as it allows the AP to send a single data stream to multiple clients, conserving bandwidth and ensuring synchronized delivery. Therefore, WLANs supporting PTT VoWiFi must be configured to handle multicast traffic effectively.

Comprehensive and Detailed Explanation:

Real-Time Location Systems (RTLS) utilize various technologies to track and locate assets or individuals in real-time. The methods include:

A. Sound:Ultrasonic sensors can be used for location tracking by measuring the time it takes for sound waves to travel between devices.

B. 802.11-capable laptops:Wi-Fi-based RTLS can leverage existing 802.11 infrastructure and devices to determine location based on signal strength and triangulation.

C. Active RFID:Active RFID tags have their own power source and can transmit signals to readers, allowing for real-time tracking over longer distances.

D. Infrared:Infrared sensors can be used for location tracking, especially in environments where line-of-sight is available.

F. UWB (Ultra-Wideband):UWB technology provides high-precision location tracking by transmitting signals over a wide frequency spectrum.

G. Passive RFID:Passive RFID tags do not have their own power source and are activated by the electromagnetic field of a reader, suitable for tracking items in close proximity.

E. UHV:Ultra-High Voltage (UHV) is not a technology used in RTLS and is therefore not applicable.

To ensure that Access Points (APs) are installed in the exact locations specified in the design, it's essential to use visual aids and physical markers.Cameras can capture images of the intended installation sites, and marking tools can be used to indicate precise mounting locations on-site.This approach minimizes errors during installation and ensures adherence to the design plan.

The CWDP-305 Official Study and Reference Guide highlights the use of such tools:

"Use cameras and marking tools to document and indicate AP placement, ensuring accurate installation according to the design."