Certified Wireless Design Professional (CWDP-305) — Questions and Answers

Question 1: What problem does IEEE 802.11k (Radio Resource Management) solve in roaming scenarios?

Provides clients with neighbor AP reports to accelerate target AP discovery (Correct answer)
Reduces re-authentication time during roaming
Controls transmit power on the client device
Enables seamless IP address retention across subnets

Correct answer: Provides clients with neighbor AP reports to accelerate target AP discovery

802.11k neighbor reports give clients a pre-built list of APs to consider for roaming, eliminating time-consuming full channel scans.

Question 2: What is the primary cause of co-channel interference in wireless networks?

Multiple access points using the same channel. (Correct answer)
High-density network design.
Overlapping coverage from different Wi-Fi networks.
Using WPA3 encryption.

Correct answer: Multiple access points using the same channel.

Co-channel interference primarily arises when multiple access points within proximity are configured to operate on the identical radio frequency channel. This overlap causes their signals to collide and interfere with each other, leading to reduced throughput, increased retransmissions, and overall degradation of wireless network performance.

Question 3: Which protocol is commonly used for network authentication in enterprise wireless networks?

WPA2-Personal
802.1X (Correct answer)
DHCP
802.11ac

Correct answer: 802.1X

802.1X is an IEEE standard for port-based network access control, widely adopted in enterprise wireless networks for robust authentication. It provides a framework for authenticating users or devices before granting them access to the network, often leveraging a RADIUS server for centralized credential management and policy enforcement, ensuring secure access.

Question 4: What is the primary purpose of a predictive site survey in WLAN design?

To count the number of client devices on the network
To measure existing wireless signal strength throughout a building
To test the speed of the current network
To model RF coverage and capacity using floor plans before deploying equipment (Correct answer)

Correct answer: To model RF coverage and capacity using floor plans before deploying equipment

Predictive site surveys use software tools to simulate RF propagation on imported floor plans, allowing designers to plan AP placement, channel assignments, and power levels before any equipment is physically installed.

Question 5: What does EIRP stand for, and why is it significant in RF channel design?

Enhanced Interference Reduction Protocol — it governs how APs reduce mutual interference
Estimated Interference and Radiation Point — it marks the location of maximum interference risk
Equivalent Integrated RF Power — it measures cumulative power across all channels
Effective Isotropic Radiated Power — it represents the total RF power output in a specific direction combining transmit power and antenna gain (Correct answer)

Correct answer: Effective Isotropic Radiated Power — it represents the total RF power output in a specific direction combining transmit power and antenna gain

EIRP (Effective Isotropic Radiated Power) is the product of transmit power and antenna gain, and it is the regulatory-controlled quantity that cannot exceed FCC limits for a given channel and band.

Question 6: What effect does each 3 dB increase in antenna gain have on the effective coverage radius (assuming free-space path loss)?

Increases radius by approximately 41% (Correct answer)
Triples the coverage radius
Doubles the coverage radius
Has no effect on coverage radius

Correct answer: Increases radius by approximately 41%

A 3 dB gain increase doubles the power density, which increases the free-space coverage radius by roughly 41%.

Question 7: In an outdoor point-to-point wireless bridge, what is the first Fresnel zone and why must it be kept clear?

The line-of-sight path that must be perfectly straight
An elliptical region around the direct path where reflections constructively interfere; obstruction causes significant signal loss (Correct answer)
The regulatory exclusion zone around outdoor APs
The antenna beam pattern measured at 3 dB below peak

Correct answer: An elliptical region around the direct path where reflections constructively interfere; obstruction causes significant signal loss

The first Fresnel zone must be at least 60% clear of obstructions to avoid destructive interference that degrades link performance.

Question 8: What is a parasitic element in antenna design used to achieve?

Modify the radiation pattern by passive coupling (Correct answer)
Increase the impedance matching bandwidth
Protect the antenna from ESD damage
Provide a DC ground path for the antenna

Correct answer: Modify the radiation pattern by passive coupling

Parasitic elements like directors and reflectors in a Yagi shape the radiation pattern without being directly fed.

Question 9: When designing an outdoor mesh for a smart city deployment, which protocol is used by mesh nodes to discover routes and forward traffic efficiently?

OSPF over wireless links
STP (Spanning Tree Protocol)
ARP flooding between mesh nodes
Hybrid Wireless Mesh Protocol (HWMP) defined in IEEE 802.11s (Correct answer)

Correct answer: Hybrid Wireless Mesh Protocol (HWMP) defined in IEEE 802.11s

IEEE 802.11s defines HWMP as the default path selection protocol for Wi-Fi mesh networks.

Question 10: Which client behavior is improved by deploying IEEE 802.11v BSS Transition Management in a high-density environment?

Load balancing by steering overloaded APs' clients to less-utilized APs (Correct answer)
Disabling power save mode on clients
Automatic channel selection by clients
Automatic IP address renewal during roam

Correct answer: Load balancing by steering overloaded APs' clients to less-utilized APs

802.11v BTM allows overloaded APs to request clients move to underutilized neighbors, improving overall load distribution.

Question 11: Which authentication method is most secure for enterprise wireless networks?

MAC address filtering.
WEP authentication.
802.1X with RADIUS authentication. (Correct answer)
Open authentication.

Correct answer: 802.1X with RADIUS authentication.

802.1X with RADIUS (Remote Authentication Dial-In User Service) is considered the most secure authentication method for enterprise wireless networks. It provides centralized authentication, authorization, and accounting (AAA) services, allowing individual user or device credentials to be verified against a central server, offering robust security and granular access control.

Question 12: Which type of site survey is performed before deploying a wireless network?

Passive survey
Post-deployment survey
Predictive survey (Correct answer)
On-demand survey

Correct answer: Predictive survey

A predictive site survey is performed before any access points are physically deployed. It utilizes software tools and floor plans to model the RF environment, estimate signal coverage, and determine optimal access point locations and configurations based on design requirements, thereby saving time and resources during the actual deployment phase.

Question 13: Which factor should be considered when deploying access points in an outdoor wireless network?

The presence of mobile devices in the area.
Only signal strength and SSID names.
Weather conditions, power availability, and obstacles. (Correct answer)
The number of available Wi-Fi channels.

Correct answer: Weather conditions, power availability, and obstacles.

Outdoor wireless deployments face unique environmental challenges. Weather conditions (rain, snow, extreme temperatures) necessitate ruggedized equipment, while power availability can be limited, requiring careful planning for power over Ethernet (PoE) or alternative solutions. Physical obstacles like trees, buildings, and terrain can also block or reflect signals, demanding meticulous planning for line-of-sight and signal propagation.

Question 14: What is the maximum channel width supported by 802.11ac Wave 2?

320 MHz
160 MHz (Correct answer)
40 MHz
80 MHz

Correct answer: 160 MHz

802.11ac Wave 2 supports channel widths up to 160 MHz (either contiguous or as 80+80 MHz non-contiguous), enabling higher throughput compared to Wave 1's maximum of 80 MHz.

Question 15: What is the main advantage of using the 5 GHz Wi-Fi band over 2.4 GHz?

Compatibility with older devices only.
Faster speeds and reduced interference. (Correct answer)
Longer range and better penetration.
Lower power consumption.

Correct answer: Faster speeds and reduced interference.

The 5 GHz band offers significantly more available channels, many of which are non-overlapping, leading to less congestion and interference compared to the crowded 2.4 GHz band. This wider spectrum also allows for larger channel widths, which directly translates to higher data rates and faster Wi-Fi speeds for connected devices.

Question 16: Which antenna characteristic describes its ability to reject interference from directions outside its main lobe?

Polarization diversity
Beamwidth
Front-to-back ratio (Correct answer)
Gain compression

Correct answer: Front-to-back ratio

The front-to-back ratio indicates how much more gain an antenna has in its main direction versus the opposite direction.

Question 17: What is the primary purpose of a wireless site survey?

To determine signal strength and interference. (Correct answer)
To configure wired network infrastructure.
To increase network bandwidth.
To install access points randomly.

Correct answer: To determine signal strength and interference.

The primary purpose of a wireless site survey is to meticulously evaluate the radio frequency (RF) environment of a specific location. This involves measuring signal strength, identifying potential sources of interference, and mapping out areas of coverage and dead zones to ensure optimal access point placement and network performance.

Question 18: What is a spectrum analysis and when should it be performed during WLAN design?

An analysis performed only after network deployment
An analysis of the RF environment to identify interference sources, performed during the site survey phase (Correct answer)
A test of the color spectrum of LED indicators on APs
A measurement of visible light interference on wireless signals

Correct answer: An analysis of the RF environment to identify interference sources, performed during the site survey phase

Spectrum analysis identifies sources of RF interference (microwave ovens, Bluetooth, radar, cordless phones) by analyzing the radio frequency spectrum, and should be performed during the site survey to inform AP placement and channel planning.

Question 19: A CWDP designer is deploying APs in a metal-shelving warehouse. What antenna placement strategy best reduces multipath?

Mount APs at floor level between aisles
Place antennas at the ends of each aisle only
Mount APs high on the ceiling above the shelving (Correct answer)
Use high-gain directional antennas at the perimeter

Correct answer: Mount APs high on the ceiling above the shelving

High ceiling mounts above shelving reduce reflections from metal surfaces and provide cleaner line-of-sight paths.

Question 20: What is co-channel interference (CCI) in a WLAN environment?

Interference caused by multipath signal reflections
Interference caused by devices operating on adjacent channels
Interference originating from non-802.11 RF emitters
Interference between access points operating on the same channel (Correct answer)

Correct answer: Interference between access points operating on the same channel

CCI occurs when two or more APs share the same channel and their coverage areas overlap, causing them to contend for airtime and degrade performance.

Question 21: What is the recommended minimum signal-to-noise ratio (SNR) for reliable VoWLAN (Voice over WLAN)?

10 dB
25 dB or higher (Correct answer)
5 dB
40 dB

Correct answer: 25 dB or higher

Voice over WLAN requires an SNR of at least 25 dB to maintain call quality, which is higher than the minimum for data applications due to voice's sensitivity to latency, jitter, and packet loss.

Question 22: What is the primary advantage of using a mesh WLAN architecture over a traditional wired infrastructure deployment in outdoor environments?

Support for more clients per access point
Lower latency for all mesh hops
Higher throughput than wired backhaul
Elimination of cabling requirements by using wireless backhaul between nodes (Correct answer)

Correct answer: Elimination of cabling requirements by using wireless backhaul between nodes

Mesh networks use wireless backhaul between nodes, avoiding the need to trench cables to every AP location.

Question 23: What is 'sticky client' behavior and why is it problematic in enterprise WLAN design?

APs that do not release client associations after timeout
Clients that maintain association with a distant AP despite a closer one being available (Correct answer)
Clients configured to use 2.4 GHz exclusively
Clients that support 802.11r and roam too frequently

Correct answer: Clients that maintain association with a distant AP despite a closer one being available

Sticky clients stay connected to a far AP with weak RSSI rather than roaming to a closer one, degrading throughput and reliability.

Question 24: What is the key benefit of using 802.11ax (Wi-Fi 6) APs in an outdoor high-density deployment such as a sports venue parking area?

Wi-Fi 6 eliminates the need for DFS in 5 GHz outdoor channels
Longer range due to lower operating frequency
OFDMA allows simultaneous transmission to multiple clients, improving efficiency in dense environments (Correct answer)
Wi-Fi 6 doubles EIRP limits compared to Wi-Fi 5

Correct answer: OFDMA allows simultaneous transmission to multiple clients, improving efficiency in dense environments

OFDMA in Wi-Fi 6 subdivides channels into resource units, enabling parallel transmissions to multiple clients and improving dense-environment efficiency.

Question 25: What is the purpose of a site survey in wireless network design?

To determine ISP availability.
To check internet speed at different locations.
To reduce the need for network security measures.
To analyze signal strength, interference, and coverage. (Correct answer)

Correct answer: To analyze signal strength, interference, and coverage.

A wireless site survey is a crucial step in designing and deploying a Wi-Fi network. Its purpose is to physically assess the environment, measuring existing RF signals, identifying sources of interference, and determining optimal access point placement to ensure adequate signal coverage and performance throughout the desired area.

Question 26: What is a key advantage of using directional antennas in wireless network design?

Eliminates the need for RF planning.
Reduces interference and improves signal strength in a specific direction. (Correct answer)
Requires fewer access points.
Covers all directions equally.

Correct answer: Reduces interference and improves signal strength in a specific direction.

Directional antennas focus their radio frequency energy into a specific direction, creating a stronger signal lobe in that intended area while minimizing signal radiation elsewhere. This focused transmission reduces interference with other devices or networks and allows for stronger, more reliable connections over longer distances in the desired direction.

Question 27: What does 'antenna gain' measure in the context of WLAN design?

Signal attenuation across free space
Total power output of the access point
Amplification of the transmit power
Concentration of radiated energy in a specific direction (Correct answer)

Correct answer: Concentration of radiated energy in a specific direction

Antenna gain measures how much energy is focused in a particular direction compared to a reference antenna.

Question 28: What is a mobility domain in the context of 802.11r fast BSS transition?

A controller cluster sharing client databases
The physical area covered by a single AP's signal
A group of APs sharing the same SSID and 802.11r configuration that allow fast roaming between them (Correct answer)
The IP subnet assigned to mobile clients

Correct answer: A group of APs sharing the same SSID and 802.11r configuration that allow fast roaming between them

An 802.11r mobility domain is identified by a Mobility Domain ID (MDID) shared among APs that support fast transitions between them.

Question 29: What tool is best suited for identifying non-Wi-Fi interference sources?

Spectrum analyzer (Correct answer)
Ping utility
Wi-Fi scanner application
Protocol analyzer (packet capture)

Correct answer: Spectrum analyzer

A spectrum analyzer shows all RF energy in the frequency band, including non-Wi-Fi sources like microwave ovens, Bluetooth devices, cordless phones, and video bridges that a Wi-Fi scanner cannot detect.

Question 30: Which factor should be considered when determining access point placement in a wireless network?

Interference and physical obstructions. (Correct answer)
The number of users on the network.
The internet speed provided by the ISP.
The color of the access point.

Correct answer: Interference and physical obstructions.

When determining access point placement, it is critical to consider potential sources of interference (e.g., other Wi-Fi networks, microwaves) and physical obstructions (e.g., walls, metal objects). These factors can severely degrade signal quality, reduce coverage, and negatively impact the overall performance of the wireless network.

Question 31: Which metric most directly indicates the wireless medium is over-subscribed, degrading VoIP quality?

Wide channel bandwidth (80 MHz)
High channel utilization above 50% (Correct answer)
Low noise floor below -90 dBm
High RSSI above -65 dBm

Correct answer: High channel utilization above 50%

Channel utilization above 50% indicates heavy contention, increasing latency and jitter that degrade real-time voice traffic.

Question 32: Which regulatory domain restriction must a CWDP consider when deploying outdoor 5 GHz point-to-point bridges in the US?

Maximum EIRP for all outdoor 5 GHz links is 20 dBm
Outdoor 5 GHz use is limited to UNII-3 channels only
UNII-2 and UNII-2 Extended channels require DFS radar detection and avoidance (Correct answer)
All 5 GHz channels are prohibited outdoors

Correct answer: UNII-2 and UNII-2 Extended channels require DFS radar detection and avoidance

UNII-2 and UNII-2e channels in the 5 GHz band require Dynamic Frequency Selection (DFS) to detect and avoid radar interference.

Question 33: Which strategy improves wireless network performance in high-density environments?

Eliminating SSID broadcast.
Deploying multiple access points with smaller coverage areas. (Correct answer)
Using a single high-power access point.
Increasing the transmission power of all APs.

Correct answer: Deploying multiple access points with smaller coverage areas.

In high-density environments, deploying multiple access points with smaller coverage areas is crucial for improving network performance. This strategy distributes the client load across more radios and allows for more efficient channel reuse, minimizing co-channel interference and maximizing overall network capacity and throughput for a large number of users.

Question 34: What IEEE amendment enables BSS Transition Management, allowing APs to suggest better APs to clients?

802.11r
802.11v (Correct answer)
802.11w
802.11k

Correct answer: 802.11v

802.11v BSS Transition Management allows APs to send BTM Request frames suggesting clients move to a better AP.

Question 35: What is the recommended minimum RSSI at the cell edge for enterprise voice (VoWLAN) applications according to CWDP design guidelines?

-67 dBm (Correct answer)
-90 dBm
-50 dBm
-80 dBm

Correct answer: -67 dBm

-67 dBm is the widely accepted minimum RSSI threshold at the cell edge for voice-grade WLAN, ensuring sufficient signal quality for low-latency, low-jitter voice traffic.

Question 36: A client is associated at -80 dBm to AP-1, and AP-2 is available at -70 dBm. The client has not roamed. What is the most likely cause?

AP-2 is on a different SSID
802.11r is not supported by AP-2
AP-1 is transmitting at higher power
The client's roaming algorithm has insufficient RSSI delta or high hysteresis (Correct answer)

Correct answer: The client's roaming algorithm has insufficient RSSI delta or high hysteresis

Some clients require a larger RSSI improvement than 10 dB or have conservative hysteresis settings that prevent them from roaming.

Question 37: In 802.11ax (Wi-Fi 6), which technology allows a single AP to serve multiple clients simultaneously on the same channel, improving spectral efficiency in channel-constrained environments?

MIMO (Multiple Input Multiple Output)
OFDM (Orthogonal Frequency Division Multiplexing)
Transmit Beamforming
OFDMA (Orthogonal Frequency Division Multiple Access) (Correct answer)

Correct answer: OFDMA (Orthogonal Frequency Division Multiple Access)

OFDMA divides a channel into smaller resource units (RUs) that can be assigned to different clients simultaneously, allowing an AP to serve multiple users in a single transmission — a key efficiency gain in Wi-Fi 6.

Question 38: A CWDP designer needs to cover a long narrow hallway. Which antenna type is most appropriate?

Omnidirectional dipole
Yagi directional (Correct answer)
Sector antenna
Patch array

Correct answer: Yagi directional

A Yagi antenna's narrow, high-gain beam pattern is well-suited for long, narrow spaces like hallways.

Question 39: What is the key advantage of 802.11r Over-the-DS (Distribution System) fast transition versus Over-the-Air?

It works without a WLAN controller
It requires no client-side 802.11r support
It allows key exchange with the target AP before the client reassociates (Correct answer)
It increases transmit power during roam

Correct answer: It allows key exchange with the target AP before the client reassociates

Over-the-DS FT pre-stages authentication keys with the target AP via the wired network before the client completes the air-interface roam.

Question 40: What is the benefit of performing an active site survey?

It eliminates interference completely.
It estimates signal coverage using software models.
It is performed without connecting to the network.
It provides real-time performance data. (Correct answer)

Correct answer: It provides real-time performance data.

An active site survey involves deploying temporary access points and connecting a survey client to them to measure actual network performance. This process allows for the collection of real-time data on signal strength, data rates, throughput, and latency, providing a highly accurate assessment of how the network will perform in practice.

Question 41: What does RF stand for in wireless communication?

Resonance Frequency
Random Frequency
Radio Frequency (Correct answer)
Rotational Frequency

Correct answer: Radio Frequency

In wireless communication, RF stands for Radio Frequency. Radio frequency refers to the oscillation rate of an alternating electric current or voltage, or of a magnetic, electric, or electromagnetic field or mechanical system, in the range from around 20 kHz to around 300 GHz. These frequencies are used to transmit and receive wireless signals, enabling technologies like Wi-Fi, Bluetooth, and cellular networks.

Question 42: What does a high percentage of management frames indicate in a wireless packet capture?

High data throughput
Possible network instability with frequent client associations, disassociations, or probe requests (Correct answer)
Encrypted traffic that cannot be analyzed
A well-optimized network

Correct answer: Possible network instability with frequent client associations, disassociations, or probe requests

A disproportionately high percentage of management frames (probe requests, authentication, association, deauthentication) suggests clients are struggling to connect or stay connected, indicating network instability.

Question 43: Which WLAN standard introduced improvements specifically beneficial for outdoor mesh networks, including better multi-hop support?

IEEE 802.11s (Correct answer)
IEEE 802.11ax (Wi-Fi 6)
IEEE 802.11p
IEEE 802.11ac Wave 2

Correct answer: IEEE 802.11s

IEEE 802.11s is the mesh networking amendment that defines peer discovery, security, and path selection for multi-hop Wi-Fi mesh.

Question 44: What is the primary purpose of TXOP (Transmission Opportunity) in 802.11e?

Assign IP DSCP values to wireless frames
Enable multi-band simultaneous transmission
Allow a station to transmit multiple frames within a bounded time period (Correct answer)
Increase the DIFS interval for high-priority traffic

Correct answer: Allow a station to transmit multiple frames within a bounded time period

TXOP grants a station a time window to send multiple frames back-to-back after winning channel access, reducing per-frame overhead.

Question 45: How does RF attenuation differ between 2.4 GHz and 5 GHz when penetrating building materials?

Both frequencies attenuate equally through all materials
5 GHz signals experience greater attenuation through most building materials than 2.4 GHz (Correct answer)
2.4 GHz experiences more attenuation than 5 GHz
Neither frequency is affected by building materials

Correct answer: 5 GHz signals experience greater attenuation through most building materials than 2.4 GHz

Higher frequency signals (5 GHz) experience greater absorption and attenuation when passing through building materials compared to lower frequency signals (2.4 GHz), resulting in shorter effective range.

Question 46: What is co-channel interference in a wireless network?

Interference caused by non-Wi-Fi devices.
Multiple access points using the same channel. (Correct answer)
Interference from neighboring networks on different channels.
Signal loss due to long-distance coverage.

Correct answer: Multiple access points using the same channel.

Co-channel interference occurs when two or more wireless access points or devices operating within the same geographical area attempt to transmit on the exact same radio frequency channel. This leads to signal collisions and retransmissions, significantly degrading network performance and throughput for all affected devices.

Question 47: When designing WLAN for a convention center with thousands of roaming attendees, which feature is most critical to prevent authentication server overload during mass roaming events?

Disabling 802.1X and using PSK instead
Increasing RADIUS server timeout values
RADIUS server load balancing only
PMK caching (OKC or 802.11r) to minimize EAP re-authentications (Correct answer)

Correct answer: PMK caching (OKC or 802.11r) to minimize EAP re-authentications

PMK caching dramatically reduces RADIUS server load by allowing most roaming events to complete without a full EAP exchange.

Question 48: How does DSCP markings relate to WMM access categories in a Voice over WLAN deployment?

DSCP is only used for wired uplink QoS
WMM replaces DSCP in all enterprise deployments
DSCP values are ignored by wireless APs
APs map DSCP values to WMM AC queues for traffic prioritization (Correct answer)

Correct answer: APs map DSCP values to WMM AC queues for traffic prioritization

APs inspect DSCP markings on incoming IP packets and map them to the appropriate WMM access category queue.

Question 49: How should channel planning be approached in a multi-floor building to minimize co-channel interference?

Assign channels randomly to each AP
Only use channel 1 throughout the building
Use a 3D channel reuse pattern ensuring the same channel is not used on adjacent APs vertically or horizontally (Correct answer)
Use the same channel on every floor for consistency

Correct answer: Use a 3D channel reuse pattern ensuring the same channel is not used on adjacent APs vertically or horizontally

A 3D channel reuse plan considers both horizontal and vertical AP adjacencies, ensuring that co-channel APs are separated by enough distance and floor attenuation to prevent significant co-channel interference.

Question 50: In WMM (Wi-Fi Multimedia), which access category has the highest priority?

Voice (AC_VO) (Correct answer)
Video (AC_VI)
Background (AC_BK)
Best Effort (AC_BE)

Correct answer: Voice (AC_VO)

AC_VO (Voice) has the shortest arbitration inter-frame spacing and smallest contention window, giving it highest channel access priority.

Question 51: What frequency bands does Wi-Fi 6E operate in?

2.4 GHz and 5 GHz only
6 GHz only
5 GHz and 6 GHz only
2.4 GHz, 5 GHz, and 6 GHz (Correct answer)

Correct answer: 2.4 GHz, 5 GHz, and 6 GHz

Wi-Fi 6E extends Wi-Fi 6 capabilities into the 6 GHz band while maintaining backward compatibility with 2.4 GHz and 5 GHz, providing up to 1200 MHz of additional spectrum.

Question 52: A CWDP is designing a wireless bridge connecting two buildings 800 meters apart. Which antenna type is most appropriate for each end?

High-gain directional antennas (Yagi or parabolic dish) at both ends (Correct answer)
Omnidirectional antennas at both ends
Sector antennas at one end and omnidirectional at the other
Patch antennas in an array configuration

Correct answer: High-gain directional antennas (Yagi or parabolic dish) at both ends

High-gain directional antennas concentrate power along the point-to-point path, providing sufficient link budget over 800 meters.

Question 53: Which IEEE amendment defines fast BSS transition (FT), reducing roaming latency for real-time applications?

IEEE 802.11u
IEEE 802.11v
IEEE 802.11k
IEEE 802.11r (Correct answer)

Correct answer: IEEE 802.11r

IEEE 802.11r defines Fast BSS Transition, enabling pre-authentication with target APs to reduce handoff time below 50 ms.

Question 54: In a Layer 3 roaming scenario, what mechanism preserves a client's IP address when crossing subnet boundaries?

Mobility tunneling (e.g., GRE tunnel back to anchor AP) (Correct answer)
VLAN trunking
DHCP relay
802.11r key caching

Correct answer: Mobility tunneling (e.g., GRE tunnel back to anchor AP)

Layer 3 roaming solutions use tunneling (GRE or proprietary) to forward client traffic back through the anchor AP, preserving the original IP.

Question 55: Which antenna type radiates energy equally in all horizontal directions, making it ideal for open-office deployments?

Yagi
Patch
Omnidirectional (Correct answer)
Parabolic

Correct answer: Omnidirectional

Omnidirectional antennas radiate in a 360-degree horizontal pattern, providing even coverage in open areas.

Question 56: Which deployment strategy helps optimize coverage in a high-density wireless environment?

Using more access points with smaller coverage cells. (Correct answer)
Disabling 5 GHz band for better range.
Ignoring interference sources.
Deploying a single high-powered access point.

Correct answer: Using more access points with smaller coverage cells.

In high-density environments, deploying more access points with reduced transmit power creates smaller, overlapping coverage cells. This strategy allows for better client load balancing across multiple APs and minimizes co-channel interference by enabling more efficient channel reuse, thereby optimizing overall network capacity and performance.

Question 57: What minimum RSSI delta between the current AP and a candidate AP typically triggers a client roam decision?

12 dB
2 dB
5 dB (Correct answer)
20 dB

Correct answer: 5 dB

Most clients require at least a 5 dB RSSI improvement at the target AP before initiating a roam to avoid unnecessary thrashing.

Question 58: A designer wants to mount antennas in the ceiling of a 10,000 sq ft warehouse. What spacing consideration is most critical?

Placing antennas only at perimeter walls
Avoiding any overlap to maximize channel reuse
Ensuring overlap of approximately 15–20% between cell edges (Correct answer)
Keeping antennas at least 50 ft apart to avoid interference

Correct answer: Ensuring overlap of approximately 15–20% between cell edges

A 15–20% cell-edge overlap ensures seamless roaming and prevents coverage gaps in large open spaces.

Question 59: A designer is planning a campus outdoor WLAN using 802.11ac APs. Which channel width provides the best balance of throughput and interference avoidance in an outdoor environment?

20 MHz channels
160 MHz channels
40 MHz channels (Correct answer)
80 MHz channels

Correct answer: 40 MHz channels

40 MHz channels in 5 GHz outdoor deployments balance throughput with sufficient spectrum availability and reduced co-channel interference risk.

Question 60: What does the Mean Opinion Score (MOS) measure in VoWLAN assessments?

RF signal strength at the client
Subjective voice quality rated on a scale of 1 to 5 (Correct answer)
Channel utilization percentage
Number of retransmissions per call

Correct answer: Subjective voice quality rated on a scale of 1 to 5

MOS is a subjective perceptual score from 1 (bad) to 5 (excellent) used to rate end-user voice quality experience.

Certified Wireless Design Professional (CWDP-305)

The CWDP-305 exam validates the knowledge and skills required to manage all stages of the Wi-Fi WLAN design life cycle, including defining specifications, designing, deploying, validating, and optimizing wireless networks. Candidates must hold a valid CWNA certification to earn the CWDP credential.

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90 min

Time Limit

70%

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