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

Question 1: 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 2: In RF design, what is the 'cell edge' and why does it matter?

The area of peak signal strength directly below the AP
The geometric center of an AP's radiation pattern
The physical wall boundary of the building envelope
The outer boundary of an AP's coverage area where signal strength approaches the minimum usable threshold (Correct answer)

Correct answer: The outer boundary of an AP's coverage area where signal strength approaches the minimum usable threshold

The cell edge is where RF signal strength drops to the minimum acceptable level; designing consistent cell edges ensures overlap between APs and reliable roaming.

Question 3: A CWDP designer is planning for 20 simultaneous VoIP calls per AP. What minimum data rate should be supported per call (G.711 codec)?

64 kbps
256 kbps
8 kbps
87.2 kbps with headers (Correct answer)

Correct answer: 87.2 kbps with headers

G.711 at 64 kbps payload plus RTP/UDP/IP/802.11 headers totals approximately 87.2 kbps per call.

Question 4: 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?

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

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

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

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

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

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

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

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

Yagi
Parabolic
Omnidirectional (Correct answer)
Patch

Correct answer: Omnidirectional

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

Question 9: Which 802.11 power save mechanism is incompatible with low-latency VoIP requirements?

WMM Power Save (U-APSD)
Target Wake Time (TWT)
Legacy 802.11 Power Save Mode (PSM) (Correct answer)
Active mode (no power save)

Correct answer: Legacy 802.11 Power Save Mode (PSM)

Legacy PSM buffers frames at the AP until the client polls, introducing unpredictable latency that disrupts real-time voice.

Question 10: A CWDP is designing a wireless bridge connecting two buildings 800 meters apart. Which antenna type is most appropriate for each end?

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

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 11: In outdoor WLAN design, what is the purpose of calculating the link budget?

Determine the regulatory EIRP limit for the deployment
Calculate the number of clients the link can support
Verify that received signal strength will exceed the receiver's sensitivity threshold with adequate margin (Correct answer)
Determine the cost of equipment for the deployment

Correct answer: Verify that received signal strength will exceed the receiver's sensitivity threshold with adequate margin

Link budget analysis ensures that transmit power, gains, losses, and path loss result in adequate received signal at the far end.

Question 12: What is 'roam thrashing' and how can a CWDP designer mitigate it?

Clients rapidly roaming between APs of similar signal strength; mitigated by hysteresis thresholds (Correct answer)
Duplicate IP assignment during roam; mitigated by DHCP snooping
Excessive AP reboots during peak traffic; resolved by firmware updates
Controller overload during mass roaming events; mitigated by load balancing

Correct answer: Clients rapidly roaming between APs of similar signal strength; mitigated by hysteresis thresholds

Roam thrashing occurs when clients oscillate between APs; RSSI hysteresis thresholds prevent roaming unless a meaningful improvement is detected.

Question 13: In a Layer 3 roaming scenario, what mechanism preserves a client's IP address when crossing subnet boundaries?

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

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

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

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 15: What factor most significantly increases free-space path loss between two outdoor wireless nodes?

Antenna polarization mismatch
Doubling the operating frequency or distance (Correct answer)
Cable losses in the transmission line
Ambient temperature above 90°F

Correct answer: Doubling the operating frequency or distance

Free-space path loss increases by 6 dB when distance or frequency doubles, as defined by the Friis transmission equation.

Question 16: What is the impact of hidden node problem on WLAN capacity?

Clients that cannot detect each other transmit simultaneously, causing collisions at the AP (Correct answer)
Hidden network names reduce available bandwidth
Access points hidden in ceiling tiles have reduced range
Clients behind walls cannot connect to the network

Correct answer: Clients that cannot detect each other transmit simultaneously, causing collisions at the AP

The hidden node problem occurs when two clients can communicate with the same AP but cannot detect each other, leading to simultaneous transmissions that collide at the AP, wasting airtime and reducing throughput.

Question 17: 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.
The number of available Wi-Fi channels.
Weather conditions, power availability, and obstacles. (Correct answer)

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 18: 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
The regulatory exclusion zone around outdoor APs
An elliptical region around the direct path where reflections constructively interfere; obstruction causes significant signal loss (Correct answer)
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 19: 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?

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

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

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

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 21: What is the benefit of using band steering in dual-band wireless networks?

Encourages devices to connect to the 5 GHz band. (Correct answer)
Forces all devices onto the 2.4 GHz band.
Reduces the need for multiple access points.
Eliminates interference in the 2.4 GHz band.

Correct answer: Encourages devices to connect to the 5 GHz band.

Band steering is a feature in dual-band access points that intelligently guides compatible client devices towards the less congested and higher-performing 5 GHz Wi-Fi band. This helps to offload traffic from the often-crowded 2.4 GHz band, improving overall network efficiency and user experience by leveraging the faster speeds and greater capacity of 5 GHz.

Question 22: What is the typical roaming latency target for seamless VoIP handoff using 802.11r?

Under 500 ms
Under 10 ms
Under 50 ms (Correct answer)
Under 150 ms

Correct answer: Under 50 ms

802.11r targets roaming latency under 50 ms to prevent audible gaps or dropped VoIP calls during AP transitions.

Question 23: Which IEEE 802.11 amendment introduced OFDMA and target wake time (TWT)?

802.11be (Wi-Fi 7)
802.11ac (Wi-Fi 5)
802.11n (Wi-Fi 4)
802.11ax (Wi-Fi 6) (Correct answer)

Correct answer: 802.11ax (Wi-Fi 6)

IEEE 802.11ax (Wi-Fi 6) introduced Orthogonal Frequency Division Multiple Access (OFDMA) for efficient multi-user uplink/downlink and Target Wake Time (TWT) for improved power management.

Question 24: In a mesh network, what is 'backhaul efficiency' and how does the number of hops affect it?

More hops increase redundancy without throughput penalty
Backhaul efficiency increases with each additional hop
Each additional mesh hop typically halves available client throughput due to half-duplex relay overhead (Correct answer)
Backhaul efficiency is independent of hop count

Correct answer: Each additional mesh hop typically halves available client throughput due to half-duplex relay overhead

Each wireless mesh hop roughly halves throughput because the relay node must receive and retransmit on the same channel.

Question 25: What IEEE amendment enables BSS Transition Management, allowing APs to suggest better APs to clients?

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

Correct answer: 802.11v

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

Question 26: What is co-channel interference (CCI) in a WLAN environment?

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)
Interference caused by multipath signal reflections

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 27: In a high-density VoWLAN deployment, what call admission control (CAC) mechanism prevents AP oversubscription?

Limiting maximum associations per AP
Disabling WMM on voice SSIDs
Using TSPEC-based admission control defined in 802.11e (Correct answer)
Assigning all VoIP to 2.4 GHz only

Correct answer: Using TSPEC-based admission control defined in 802.11e

TSPEC (Traffic Specification) admission control allows the AP to accept or reject new voice streams based on available bandwidth.

Question 28: Which deployment strategy helps optimize coverage in a high-density wireless environment?

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

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 29: 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
Use high-gain directional antennas at the perimeter
Mount APs high on the ceiling above the shelving (Correct answer)
Place antennas at the ends of each aisle only

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

2 dB
12 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 31: What does EIRP stand for and what does it represent in WLAN design?

Equivalent Internal Radio Power — power consumed by the radio chipset
Estimated Interference Reduction Parameter — a planning metric
Enhanced Interference Rejection Protocol — a filtering mechanism
Effective Isotropic Radiated Power — total power radiated by the antenna system (Correct answer)

Correct answer: Effective Isotropic Radiated Power — total power radiated by the antenna system

EIRP is the effective isotropic radiated power, combining transmit power and antenna gain minus cable losses.

Question 32: What is the most common cause of sticky client behavior in enterprise WLANs?

Clients frequently disconnecting and reconnecting
Clients maintaining association with a distant AP instead of roaming to a closer one (Correct answer)
Excessive DHCP lease times
Too many SSIDs configured on the network

Correct answer: Clients maintaining association with a distant AP instead of roaming to a closer one

Sticky clients occur when devices maintain their connection to the original AP even after moving to an area better served by another AP, often due to the client's roaming algorithm threshold being too conservative.

Question 33: What is the benefit of performing an active site survey?

It eliminates interference completely.
It is performed without connecting to the network.
It estimates signal coverage using software models.
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 34: What path loss model is most commonly used for outdoor WLAN link budget calculations in open terrain?

Log-distance indoor model
Two-ray ground reflection model
ITU indoor model
Free-Space Path Loss (Friis) model (Correct answer)

Correct answer: Free-Space Path Loss (Friis) model

The Friis free-space path loss model is used for outdoor line-of-sight links, calculating loss based on distance and frequency.

Question 35: What is the primary difference between a wireless bridge and a wireless mesh node?

Bridges use 802.11n only; mesh uses 802.11ac
Mesh nodes require wired uplink; bridges do not
Bridges require line-of-sight; mesh operates only indoors
A bridge connects two fixed points; a mesh node dynamically routes through multiple paths (Correct answer)

Correct answer: A bridge connects two fixed points; a mesh node dynamically routes through multiple paths

Wireless bridges create fixed point-to-point or point-to-multipoint links, while mesh nodes dynamically discover and route through multiple paths.

Question 36: 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
Higher throughput than wired backhaul
Elimination of cabling requirements by using wireless backhaul between nodes (Correct answer)
Lower latency for all mesh hops

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 37: A CWDP is designing a parking lot WLAN using outdoor APs. What IP67 rating indicates about the AP enclosure?

The enclosure is dust-tight and protected against immersion up to 1 meter for 30 minutes (Correct answer)
The AP has 6 radios and 7 antenna ports
The AP supports 6 GHz Wi-Fi and 7 watts of PoE
The AP meets IEEE 802.11 revision 6.7 specifications

Correct answer: The enclosure is dust-tight and protected against immersion up to 1 meter for 30 minutes

IP67 means the enclosure is fully dust-tight (6) and can withstand water immersion up to 1 meter for 30 minutes (7).

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

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

Correct answer: Yagi directional

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

Question 39: Which regulatory body in the US governs outdoor WLAN antenna and power limits?

FCC (Correct answer)
Wi-Fi Alliance
IEEE
NIST

Correct answer: FCC

The Federal Communications Commission (FCC) regulates RF emissions, power levels, and antenna use under Part 15 rules.

Question 40: Which client behavior is improved by deploying IEEE 802.11v BSS Transition Management in a high-density environment?

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

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 41: How does transmit power mismatch between APs and clients affect network performance?

It causes the AP to overheat
It only affects battery life on the client device
It has no effect on performance
Clients may hear the AP but cannot transmit back reliably, creating asymmetric communication (Correct answer)

Correct answer: Clients may hear the AP but cannot transmit back reliably, creating asymmetric communication

When an AP transmits at much higher power than the client device, the client can receive the AP's signal from far away but its lower-power response may not reach the AP, creating an asymmetric link with poor performance.

Question 42: What does EIRP stand for, and why is it significant in RF channel design?

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

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

IEEE 802.11u
IEEE 802.11k
IEEE 802.11v
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 44: Which channel planning approach is preferred in high-density venues such as conference centers or stadiums?

2.4 GHz-only deployment for maximum range
All APs set to the same channel for seamless roaming
5 GHz-only deployment with 20 MHz channels to maximize non-overlapping channel count (Correct answer)
Mixed 2.4/5 GHz with 80 MHz channel bonding throughout

Correct answer: 5 GHz-only deployment with 20 MHz channels to maximize non-overlapping channel count

5 GHz-only with 20 MHz channels provides the most non-overlapping channels and avoids the congested 2.4 GHz band, which is essential when many APs and clients coexist in a small area.

Question 45: Why is antenna impedance matching (typically 50 ohms) important in WLAN installations?

It controls the output power of the AP radio
It maximizes power transfer and minimizes reflected power (Correct answer)
It sets the polarization of the antenna
It determines the operating frequency of the antenna

Correct answer: It maximizes power transfer and minimizes reflected power

Matched impedance minimizes standing wave ratio (SWR), ensuring maximum power is radiated rather than reflected.

Question 46: What is the difference between a passive and active site survey?

Passive surveys use fewer tools than active surveys
Passive surveys are done at night; active surveys during business hours
Passive surveys listen to existing RF without associating; active surveys connect to the network and measure performance (Correct answer)
There is no difference in the data collected

Correct answer: Passive surveys listen to existing RF without associating; active surveys connect to the network and measure performance

Passive surveys capture RF data (signal strength, noise, interference) without connecting to any network, while active surveys associate with the WLAN and measure actual throughput, latency, packet loss, and roaming behavior.

Question 47: What effect does each 3 dB increase in antenna gain have on the effective coverage radius (assuming free-space path loss)?

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

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

Only use channel 1 throughout the building
Assign channels randomly to each AP
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 49: In the US, the FCC limits maximum EIRP for point-to-multipoint 5 GHz outdoor links to which value?

40 dBm
36 dBm (Correct answer)
53 dBm
30 dBm

Correct answer: 36 dBm

The FCC limits point-to-multipoint EIRP in the 5 GHz UNII bands to 36 dBm for outdoor use.

Question 50: What does 'antenna gain' measure in the context of WLAN design?

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

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 51: What information should be gathered during a pre-survey site visit?

Only the number of rooms in the building
Previous tenant's network design documents only
The building's electrical consumption data
Building materials, ceiling heights, existing infrastructure, RF interference sources, and client requirements (Correct answer)

Correct answer: Building materials, ceiling heights, existing infrastructure, RF interference sources, and client requirements

A thorough pre-survey visit documents construction materials (wall composition, glass types), ceiling types and heights, existing cabling and mounting points, potential RF interference sources, aesthetic requirements, and client needs.

Question 52: What is Adjacent Channel Interference (ACI) in wireless networking?

Interference between APs using identical channels
Interference caused by the same SSID broadcasted on multiple APs
Interference from external RF sources outside the building
Interference between APs on channels that partially overlap in frequency (Correct answer)

Correct answer: Interference between APs on channels that partially overlap in frequency

ACI occurs when APs use channels that are close but not identical in frequency, causing partial spectral overlap that degrades signal quality.

Question 53: What is the primary goal of channel planning in a WLAN deployment?

Maximize the number of access points deployed
Reduce the total number of SSIDs broadcasted
Increase transmit power across all access points
Minimize co-channel interference between access points (Correct answer)

Correct answer: Minimize co-channel interference between access points

Channel planning aims to minimize co-channel interference by ensuring APs using the same channel are spaced far enough apart that their signals do not significantly overlap.

Question 54: What design technique allows a mesh AP to avoid throughput halving by separating backhaul and access traffic?

Using 2.4 GHz exclusively for backhaul
Deploying dual-radio or tri-radio mesh nodes with dedicated backhaul radios (Correct answer)
Using the same channel for both backhaul and access
Increasing transmit power on the mesh node

Correct answer: Deploying dual-radio or tri-radio mesh nodes with dedicated backhaul radios

Dedicated backhaul radios (on a separate channel or band) allow simultaneous backhaul and client access without sharing the medium.

Question 55: In a CWDP design, what is the purpose of 'band steering' in relation to client mobility?

Prevent clients from roaming between APs
Force clients to use 5 GHz to reduce 2.4 GHz congestion (Correct answer)
Increase transmit power on 5 GHz to attract clients
Assign clients to specific channels based on RSSI

Correct answer: Force clients to use 5 GHz to reduce 2.4 GHz congestion

Band steering encourages capable clients to associate on 5 GHz, freeing 2.4 GHz for legacy devices and reducing interference.

Question 56: Which factor should be considered when determining access point placement in a wireless network?

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

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

Post-deployment survey
Passive 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 58: In the 802.11r fast transition process, what is the role of the 'R0 Key Holder'?

The first AP in the mobility domain that derives the master session key (Correct answer)
The RADIUS server that stores EAP credentials
The controller that manages IP address assignment
The client that initiates the roam request

Correct answer: The first AP in the mobility domain that derives the master session key

The R0 Key Holder (typically the original authenticating AP or controller) holds the top-level PMK-R0 from which all roaming keys are derived.

Question 59: What does the Mean Opinion Score (MOS) measure in VoWLAN assessments?

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

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.

Question 60: What is the main advantage of using the 5 GHz Wi-Fi band over 2.4 GHz?

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

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.

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

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70%

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