CWNP CWDP-305 Certified Wireless Design Professional Exam Practice Test

Channel bonding is a feature introduced in 802.11n and enhanced in 802.11ac that allows the combination of two adjacent channels to double the channel width, thereby increasing throughput. However, 1x1:1 client devices, which have a single transmit and receive antenna and support only one spatial stream, often lack the capability to utilize channel bonding effectively. These low-end devices are limited in their hardware and cannot take full advantage of the increased bandwidth that channel bonding offers.

In high-density environments with limited DHCP address pools, it's crucial to manage IP address allocation efficiently. Reducing the DHCP lease time to a shorter duration, such as 20 minutes, ensures that IP addresses are recycled more frequently. This approach minimizes the risk of address exhaustion by promptly reclaiming addresses from devices that disconnect or become inactive. While adjusting client timeouts and maximum client limits can help manage network load, they don't directly influence DHCP address utilization.

A survey tray is a lightweight, portable platform that allows WLAN engineers to carry laptops and survey gear comfortably while walking and taking measurements. It helps maintain posture and prevents strain during long survey sessions.

From CWDP-305:

“Using a survey tray allows the engineer to maintain proper posture and prevent back strain while conducting extended walkabouts during site surveys.”

— Reference: CWDP-305 Official Study and Reference Guide, Chapter on Advanced Site Surveys

Comprehensive and Detailed Explanation:

Real Time FFT stands for Real Time Fast Fourier Transform.It is a spectrum analysis tool that displays the maximum signal amplitude detected at each frequency in real time.This visualization helps in identifying transient RF events, such as sporadic interference or brief signal spikes, which might not be captured in averaged spectrum analyses.By providing immediate feedback on the RF environment, Real Time FFT graphs are invaluable for troubleshooting and optimizing WLAN performance.

Comprehensive and Detailed Explanation:

When designing a WLAN for a new facility, especially one that hasn't been constructed yet, apredictive site surveyis the most appropriate initial step. Predictive surveys utilize software tools to model RF behavior based on building materials, floor plans, and environmental factors. This method allows for planning of AP placements, channel assignments, and coverage areas without the need for physical access to the site.

Given the requirements for dual-spectrum 802.11n, voice support, and location tracking, a predictive survey can help in:

Estimating the number and placement of APs to ensure adequate coverage and capacity.

Planning for voice over WLAN (VoWLAN) by modeling for low-latency and seamless roaming.

Designing for location tracking by ensuring sufficient AP density and placement for accurate triangulation.

For 802.3bz MultiGig Ethernet, which supports speeds of 2.5 Gbps and 5 Gbps over twisted-pair cabling, the recommended cabling standards vary based on the distance:

Cat-5e: Suitable for 2.5 Gbps up to 100 meters; 5 Gbps up to 55 meters

Cat-6: Suitable for 5 Gbps up to 55 meters

Cat-6a: Suitable for 10 Gbps up to 100 meters

Given that some cable runs will exceed 55 meters, Cat-6a is the most appropriate choice to ensure reliable MultiGig performance over longer distances.

Comprehensive and Detailed Explanation:

Involving end-users in the final meeting ensures that the WLAN infrastructure meets their needs and expectations.Their feedback is crucial for validating the network's performance and usability, as they are the primary users who will interact with the system daily.

Importing a scaled floor plan is one of the very first steps required in wireless design tools. This serves as the canvas upon which walls, attenuation, and APs will be layered. Without a floor plan, no spatial or RF modeling can occur.

From CWDP-305:

“A properly scaled and oriented floor plan is the foundation of a design. It should be imported early in the process before defining wall types, coverage areas, or AP placements.”

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

Comprehensive and Detailed Explanation:

EAP (Extensible Authentication Protocol) messages are encapsulated withinEAP over LAN (EAPOL)frames when transmitted over 802.11 wireless networks. EAPOL operates at the data link layer and is part of the 802.1X standard, facilitating authentication between the client (supplicant) and the authentication server.

A.EAP-Fast is an EAP method, not the transport mechanism.

B.PEAP is another EAP method that encapsulates EAP within a TLS tunnel.

D.EAP-TLS is an EAP method utilizing TLS for authentication.

Laptops are more likely to support advanced wireless features such as 3x3:3 Multiple Input Multiple Output (MIMO) configurations and 256 Quadrature Amplitude Modulation (QAM), which are integral to achieving the higher data rates offered by 802.11ac. These devices typically have the physical space and power resources to accommodate multiple antennas and the processing capabilities required for such advanced features.

In contrast, devices like handheld scanners, tablets, USB 2.0 adapters, and mobile phones are often limited to 1x1 or 2x2 MIMO configurations due to size, power, and cost constraints, making them less likely to support 3x3:3 MIMO and 256 QAM.

Conducting site surveys in environments like heavy machinery repair facilities presents unique safety challenges. These areas may have hazards such as moving equipment, loud noises, and airborne particles. To ensure personal safety, surveyors must wear Personal Protective Equipment (PPE), which may include hard hats, safety glasses, ear protection, and steel-toed boots.

The CWDP-305 exam objectives emphasize the importance of safety during site surveys, stating the need to:

"Select and use appropriate design methodologies... Cameras; Personal Protective Equipment (PPE)."

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This underscores the necessity of PPE in certain survey environments.

Options like low gain antennas, low power APs, and indoor APs pertain to technical aspects of the survey but do not address the safety requirements of the surveyor.

Site survey adapters are often specialized devices with enhanced sensitivity and performance characteristics compared to standard client Wi-Fi adapters.These specialized adapters can detect weaker signals and provide more detailed RF information, leading to higher RSSI readings during surveys.Consequently, standard client devices may experience lower RSSI values in the same environment.

The CWDP-305 Official Study and Reference Guide notes:MetaGeek Community

"Survey adapters are typically more sensitive than standard client devices, which can result in discrepancies between survey data and actual client experiences."

Comprehensive and Detailed Explanation:

In scenarios where the 2.4 GHz radio is not used for standard access point operations, it can be repurposed for functions such as security monitoring. Utilizing the 2.4 GHz radio for monitoring allows the network to detect unauthorized devices, rogue APs, and potential security threats, thereby enhancing the overall security posture of the wireless network.

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.

In wireless networks, devices dynamically adjust their physical layer (PHY) data rates based on the quality of the radio frequency (RF) environment. Several factors influence a device's decision to lower its PHY rate:

Signal degradation: As the signal strength weakens due to distance or obstacles, the device may lower its data rate to maintain a reliable connection.

Interference: The presence of other RF signals can cause interference, leading the device to reduce its data rate to mitigate potential errors.

Retransmissions: An increase in retransmissions indicates that frames are not being successfully received, prompting the device to lower its data rate to improve reliability.

While packet loss is a consequence of these factors, it is not a direct cause for adjusting the PHY rate.

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:

Hiding the Service Set Identifier (SSID) can serve specific purposes, such as:

Preventing guests from attempting to join the secured corporate network:By not broadcasting the corporate SSID, casual users are less likely to attempt connections, reducing unauthorized access attempts.

Minimizing help desk calls from users and guests attempting to join the wrong network:When only the guest network SSID is visible, it simplifies the connection process for visitors, leading to fewer support requests.

However, it's important to note that SSID hiding is not a robust security measure. Determined attackers can still detect hidden networks using various tools, as the SSID can be revealed in certain management frames like probe requests and association requests.

WPA/WPA2-Enterprise provides enhanced security features suitable for enterprise environments, such as per-user authentication and dynamic encryption keys. However, these benefits come with certain drawbacks not present in WPA/WPA2-Personal:

Additional Infrastructure Requirements:WPA/WPA2-Enterprise typically requires a RADIUS server to handle authentication, which adds complexity and cost to the network infrastructure.

Increased Administrative Overhead:Configuring and maintaining WPA/WPA2-Enterprise involves managing user credentials, certificates, and RADIUS server settings, which demands more administrative effort compared to the simpler pre-shared key setup of WPA/WPA2-Personal.

It's important to note that WPA/WPA2-Enterprise does support the use of usernames and passwords for client authentication and provides mechanisms for per-user authorization and access control. While X.509 certificates are commonly used for server authentication in WPA/WPA2-Enterprise, they are not strictly required in all configurations.

The control plane in WLAN architectures is responsible for managing and optimizing various network functions to ensure efficient and reliable wireless communication. Key functions include:

Channel Reuse Plans:Determining optimal channel assignments to minimize interference and maximize spectrum efficiency.

Mobility Management:Facilitating seamless client roaming between access points without service interruption.

Transmit Power:Adjusting the power levels of access points to ensure adequate coverage while reducing interference.

Load Balancing:Distributing client connections across multiple access points to prevent overloading and maintain performance.

These functions are critical in both centralized and distributed WLAN architectures to maintain optimal network performance and user experience.

Allowing employees to use their own devices on the company network—commonly known as BYOD (Bring Your Own Device)—can provide several operational benefits:

Enhanced Productivity:Users are more familiar and comfortable with their personal devices, leading to faster adoption and efficiency.

Decreased Costs:The organization can reduce capital expenditures on hardware purchases and lifecycle management.

Increased Satisfaction:Employees prefer working on familiar platforms, which contributes to higher morale and satisfaction.

From the CWDP-305 guide:

“BYOD deployments can enhance user satisfaction and productivity while reducing costs associated with device provisioning. However, they require proper security and access controls.”

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

Comprehensive and Detailed Explanation:

For reliable Voice over Wi-Fi (VoWiFi) service, a minimum RSSI of -67 dBm is generally recommended. This level ensures sufficient signal strength to support the quality of service required for voice applications, providing adequate signal-to-noise ratio (SNR) and minimizing the likelihood of dropped calls or poor audio quality.

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.

To measure performance metrics such as throughput and latency, you must associate with the AP and generate/receive real traffic. This type of survey is called an active survey.

From CWDP-305:

“Active surveys assess the end-user experience by collecting real-time data, such as throughput, latency, and packet loss, which cannot be captured by passive surveys.”

Passive surveys only collect information from beacons and probe responses without associating with the AP.

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

Comprehensive and Detailed Explanation:

In the final meeting after successfully implementing a WLAN infrastructure, it is essential to have the acquirer and key stakeholders from the customer side present. The acquirer is typically the individual or group responsible for procuring the WLAN solution, while stakeholders include those who have an interest in the project's success, such as IT managers, network administrators, and department heads. Their presence ensures that the implementation aligns with the organization's requirements and expectations, and it provides an opportunity to address any concerns or questions before project closure.

Comprehensive and Detailed Explanation:

In predictive modeling for WLAN design:

B.Setting the AP transmit power to match the average client device capabilities (e.g., 25 mW) ensures a balanced link budget, promoting reliable two-way communication and accurate coverage predictions.

A.While default antenna patterns can be used, they may not accurately represent the actual deployment, especially if different antennas are planned.

C.Channel width settings should reflect the intended deployment plan, which may include 20 MHz, 40 MHz, or 80 MHz channels, depending on the environment and requirements.

D.Using pre-configured vendor-specific AP and antenna models in the predictive software ensures that thesimul-ationclosely matches the actual hardware characteristics, leading to more accurate predictions.

Remote Authentication Dial-In User Service (RADIUS) is a networking protocol that provides centralized Authentication, Authorization, and Accounting (AAA) management for users who connect and use a network service.When integrating with an LDAP directory, RADIUS servers can authenticate users against the LDAP database before granting access to the WLAN infrastructure.

The CWDP-305 Official Study and Reference Guide notes:

"What service must be implemented on your customer's network to authenticate users against an LDAP database before granting access to the WLAN infrastructure? B. RADIUS"Pass4Success

If QoS markings are correct from the client to the AP but incorrect from the AP to the client, it's likely that the QoS markings are being stripped or not trusted somewhere on the wired network between the controller and the AP. This misconfiguration can result in the AP transmitting frames without the appropriate QoS markings, affecting voice quality.

Starting with a Tx Power Level of "1" at 17 dBm, each increment halves the power:

Level 2: 17 dBm - 3 dB = 14 dBm

Level 3: 14 dBm - 3 dB = 11 dBm

Level 4: 11 dBm - 3 dB = 8 dBm

Converting 8 dBm to mW:

10^(8/10) ≈ 6.31 mW

The closest provided option is 6.25 mW.

Comprehensive and Detailed Explanation:

In 802.11b, the 1 Mbps data rate usesDirect Sequence Spread Spectrum (DSSS)with an 11-bit Barker code. Each bit of data is represented by an 11-chip sequence, resulting in a chip rate of:

1 Mbps × 11 chips/bit = 11 Mchips/s

However, thechip raterefers to the rate at which the chips (the smaller units of data in DSSS) are transmitted. For 802.11b, the chip rate is11 Mchips/sfor the 1 Mbps data rate.

If a persistent source of interference cannot be removed, the best course of action is to design around it—usually by changing channels to avoid the affected frequencies. This minimizes the impact on WLAN operation while still coexisting with the interfering device.

From CWDP-305:

“If interference is detected during post-deployment validation and cannot be mitigated by removal, channel reallocation is the most effective way to work around the problem without affecting WLAN integrity.”

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

Comprehensive and Detailed Explanation:

Transitioning from a centralized to a distributed data forwarding model can introduce compatibility issues. Specifically:

C.Some APs designed for centralized architectures may lack the necessary hardware or firmware capabilities to support distributed forwarding features, such as local breakout or direct client-to-client communication, leading to potential limitations in functionality.

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

Comprehensive and Detailed Explanation:

In WLANs, excessive retransmissions of Real-time Transport Protocol (RTP) frames, often due to interference or poor signal quality, can trigger the rate adaptation algorithm in client devices. This algorithm reduces the data transmission rate to maintain connectivity, which can lead to increased latency and degraded voice quality.

Comprehensive and Detailed Explanation:

The SKINNY protocol, also known as the Skinny Client Control Protocol (SCCP), is a proprietary protocol used by Cisco for VoIP signaling between endpoints and call managers. Its presence in a protocol capture indicates that VoIP services are active on the network.

Comprehensive and Detailed Explanation:

The Duty Cycle view in a spectrum analyzer indicates the percentage of time a frequency is occupied by RF transmissions. By analyzing the duty cycle, you can assess whether a channel is too congested for additional AP deployment. A high duty cycle suggests that the channel is frequently used, which could lead to increased contention and degraded performance if another AP is added.

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.

Comprehensive and Detailed Explanation:

When transitioning from a centralized to a distributed data forwarding model in a WLAN architecture, it's important to consider the capabilities of the existing APs. Some APs designed specifically for centralized forwarding may lack the necessary hardware or firmware support to operate effectively in a distributed forwarding mode. This can lead to compatibility issues and may require hardware upgrades or replacements to ensure proper functionality in the new architecture.

In environments with high-security restrictions, such as meat processing facilities, it's imperative to obtain the necessary access and clearance before conducting a site survey.This ensures compliance with security protocols and prevents unauthorized access to sensitive areas.

The CWDP-305 Official Study and Reference Guide emphasizes the importance of adhering to site-specific security requirements during site surveys.

In the 5 GHz band, the number of available non-overlapping 40 MHz channels without DFS (Dynamic Frequency Selection) varies by regulatory domain. Typically, the UNII-1 and UNII-3 bands are available without DFS requirements.

Each 40 MHz channel requires two adjacent 20 MHz channels. Considering the available spectrum and avoiding DFS channels, you can typically configure three non-overlapping 40 MHz channels.

Comprehensive and Detailed Explanation:

iPerf is a widely used network testing tool that measures the maximum achievable bandwidth on IP networks. In the context of wireless site surveys and validation, iPerf is utilized to perform throughput testing, providing insights into the data transfer rates between devices. This information is vital for assessing the performance of the wireless network and ensuring it meets the required specifications.

Band steering is a technique used to encourage dual-band clients to connect to the less congested 5 GHz band.However, some clients may not respond to steering attempts and persist in attempting to connect on the 2.4 GHz band.To ensure connectivity for these persistent clients, APs are designed to eventually respond to their Probe Requests on the 2.4 GHz band after a certain number of ignored attempts.

The CWDP-305 Official Study and Reference Guide states:

"Band steering mechanisms must account for clients that do not support or respond to steering attempts, allowing them to connect on the 2.4 GHz band after a defined number of ignored Probe Requests."

The Friis transmission equation is used to calculate the free-space path loss (FSPL) between two antennas.It considers the distance (d) between the antennas and the frequency (f) of the transmitted signal.This equation is fundamental in wireless design to estimate the loss of signal strength over a line-of-sight path, aiding in link budget calculations and ensuring reliable communication.

When calculating the total noise figure of cascaded components, Friis' formula is used:

F_total = F1 + (F2 - 1)/G1 + (F3 - 1)/(G1 × G2) + ...

Where:

F_totalis the total noise factor (linear, not in dB).

F1, F2, ...are the noise factors of the individual stages.

G1, G2, ...are the gains of the preceding stages (linear, not in dB).

In this scenario, the amplifier has a gain of 0 dB, which corresponds to a linear gain of 1. A noise figure of 10 dB corresponds to a noise factor of 10. Assuming the cable and filter have negligible noise contributions or are passive components with minimal loss, their impact on the total noise figure is minimal.

Applying Friis' formula:

F_total = 10 + (1 - 1)/1 = 10

Converting back to dB:

NF_total = 10 × log10(10) = 10 dB

As client density increases, the demand for IP address allocation also increases. In this scenario, the transition from a lightly used 802.11g environment to a high-density 802.11ax deployment (Wi-Fi 6) introduces a significantly larger number of devices.

From CWDP-305:

“DHCP scope exhaustion is a common issue in high-density environments. The DHCP server must be configured to support large address pools to ensure clients can successfully obtain IP addresses.”

Thus, verifying and possibly expanding DHCP pools is essential to prevent connection failures due to address depletion.

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

Comprehensive and Detailed Explanation:

Multicasting is a network capability that allows a single data stream to be transmitted to multiple recipients simultaneously, which is highly efficient for live video streaming applications. By configuring multicasting in WLAN implementations, bandwidth usage is optimized, and network congestion is reduced, as the same data does not need to be sent individually to each client. Implementing multicast support ensures that all intended recipients receive the video stream with minimal latency and resource utilization.

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.

Effective Isotropic Radiated Power (EIRP) is calculated by adding the transmit power (in dBm) to the antenna gain (in dBi).

Transmit power: 25 mW = 14 dBm

Antenna gain: 3 dBi

EIRP = 14 dBm + 3 dBi = 17 dBm

The CWDP-305 Official Study and Reference Guide provides guidance on calculating EIRP to ensure compliance with regulatory limits and optimal network performance:

"EIRP is the sum of the transmitter output power and the antenna gain, accounting for any losses. Accurate EIRP calculations are essential for regulatory compliance and effective wireless design."

802.11r Fast Transition (FT) defines two methods to facilitate quick and secure roaming between access points:

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

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Over-the-DS (Distribution System): The client communicates with the current AP, which then relays the authentication information to the target AP over the wired network.

Both methods aim to reduce latency during the roaming process, ensuring seamless connectivity for applications sensitive to delays, such as VoIP.

extreme-networks.my.site.com

In North America, Wi-Fi devices operating in the 2.4 GHz band are typically restricted to channels 1 through 11. However, in Europe, channels 12 and 13 are also permitted. If a European AP is configured to operate on channel 13, a North American device may not recognize or connect to it, leading to low RSSI readings or inability to connect.

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In this scenario, the AP in the room is likely operating on channel 13, which the traveler's device cannot utilize, resulting in low RSSI. Conversely, the lobby APs are operating on channels 1 through 11, which are compatible with the traveler's device, leading to normal RSSI readings.

Other options, such as the AP using ZigBee or Bluetooth, are unlikely, as these technologies are distinct from Wi-Fi and would not present as Wi-Fi SSIDs. The switchport speed, while affecting throughput, does not directly impact RSSI.

An active site survey involves connecting a client device to the WLAN and measuring various performance metrics such as throughput, latency, and roaming behavior. This type of survey is essential for validating that roaming is functioning as intended, as it allows the surveyor to observe the client's ability to maintain a stable connection while moving between access points.

The 6 GHz band, introduced with Wi-Fi 6E (802.11ax), mandates the use of WPA3 security protocols. Specifically, WPA3-Personal and WPA3-Enterprise are required for networks operating in this band. WPA2-Personal is not permitted in the 6 GHz spectrum due to regulatory and security requirements.

Therefore, recommending WPA2-Personal for VoIP support in the 6 GHz band is technically inappropriate, as it does not comply with the mandatory security standards for this frequency range.

Comprehensive and Detailed Explanation:

In designing Point-to-Point (PTP) outdoor wireless links, local vegetation plays a significant role in signal propagation and potential attenuation. Key considerations include:

A. Leaves:Foliage, especially leaves, can absorb and scatter RF signals, particularly at higher frequencies. Seasonal changes can affect signal strength due to varying leaf density.

B. Tree height growth:Over time, trees can grow into the line-of-sight path, causing signal obstruction. Planning should account for potential future growth to maintain clear paths.

C. Water density:Vegetation with high water content can absorb RF energy, leading to increased signal attenuation. This is especially pertinent in areas with lush, dense foliage.

D. Reflection factor:While reflections can impact signal quality, in the context of vegetation, absorption and scattering are more critical factors than reflection.

Configuration backups are a critical component of operational and maintenance plans.They ensure that, in the event of a failure or misconfiguration, the network can be restored to a known good state quickly.Despite their importance, configuration backups are often overlooked, leading to prolonged downtimes and increased recovery times during network issues.

Accurate WLAN design relies heavily on the precision of the floor plan used in predictive modeling tools. Before placing Access Points (APs), antennas, or defining attenuation factors, it's imperative to calibrate the floor plan. This involves setting a known scale, typically by measuring a known distance within the plan, to ensure that the software accurately represents real-world dimensions.

Proper calibration ensures that signal propagation, coverage areas, and interference zones are accurately predicted, leading to a more reliable and efficient WLAN design.

Comprehensive and Detailed Explanation:

Per-user Pre-Shared Keys (PSKs) offer several advantages over a single PSK used across an entire Extended Service Set (ESS):

User-Based Access Control:Assigning unique PSKs to individual users allows for better tracking and control over network access.

Simplified Key Management:If a user's PSK is compromised or they leave the organization, only their key needs to be changed, not the entire network's.

Option C:Per-user PSKs are not a standard defined or certified by the Wi-Fi Alliance; they are an implementation choice.

Option D:Mutual authentication is a feature of WPA/WPA2-Enterprise using 802.1X, not of PSK-based systems.

Receive sensitivity indicates the minimum signal strength at which a device can successfully receive and demodulate a signal at a specified data rate.In this case, a receive sensitivity of −82 dBm @ 18 Mbps means that the device requires a signal stronger than −82 dBm to reliably demodulate data at 18 Mbps.Therefore, the device must receive a signal with a strength greater than −82 dBm (i.e., closer to 0 dBm) to maintain that data rate.

Comprehensive and Detailed Explanation:

Latency is a critical metric when designing WLANs for VoIP (Voice over IP) applications. High latency can result in poor call quality, including delays and echoes. Industry standards recommend that one-way latency should not exceed 150 milliseconds to maintain acceptable voice quality. Therefore, during site surveys and network design, measuring and minimizing latency is essential to ensure a high-quality VoIP experience.

Wi-Fi Multimedia (WMM) is a subset of the IEEE 802.11e standard and is essential for enabling Quality of Service (QoS) features in Wi-Fi networks. When WMM is not enabled on an 802.11n WLAN, QoS features are unavailable, which can adversely affect the performance of latency-sensitive applications such as voice over IP (VoIP) and video streaming.گروه آموزشی و پژوهشی سیب

Additionally, certain 802.11n features, like higher data rates and frame aggregation, may not be fully utilized without WMM, leading to suboptimal network performance.

PMK caching(Pairwise Master Key caching) is a roaming technology where the access point (AP) stores the PMK derived during the initial authentication of a client station (STA).If the client roams away and then returns to the same AP, the stored PMK allows for a quicker re-association without the need for a full authentication process.

This mechanism enhances roaming efficiency by reducing latency during re-association, which is particularly beneficial for applications sensitive to delays, such as VoIP.

Dynamic Channel Assignment (DCA) algorithms optimize the RF environment by automatically selecting channel assignments based on factors like interference, noise, and utilization. However, DCA requires tuning of algorithm parameters to align with the specific design and site requirements.

From CWDP-305:

“Dynamic channel assignment and transmit power control must be configured according to the design goals and validated after deployment. Default settings may not produce optimal results in all environments.”

Simply relying on default settings without adjustment can lead to poor RF behavior.

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

The introduction of a new requirement, such as supporting RFID location tracking, after the site survey has commenced constitutes scope creep.Scope creep refers to the uncontrolled expansion of project scope without corresponding adjustments to time, cost, and resources.Implementing location tracking requires specific design considerations, including AP placement and calibration, which should be planned from the project's outset.Introducing such requirements mid-project can lead to design inefficiencies and increased costs.

Comprehensive and Detailed Explanation:

Designing a guest network in a large enterprise involves several considerations to ensure security, performance, and user experience:

Rate limiting:Implementing bandwidth controls prevents guest users from consuming excessive network resources, ensuring that corporate users maintain optimal performance.

Traffic tunneling or anchoring:Redirecting guest traffic through a centralized point (such as a DMZ or a dedicated internet connection) isolates it from the corporate network, enhancing security.

SSID segmentation:Using separate SSIDs for guest and corporate networks allows for distinct policy enforcement, access controls, and network segmentation.

Option A:While 802.11n provides higher throughput, it's a standard feature and not a specific design consideration for guest networks.

Option C:802.1X security is typically used for enterprise networks requiring individual authentication. Guest networks often use simpler authentication methods like captive portals.

To authenticate users against an LDAP database for WLAN access, a RADIUS (Remote Authentication Dial-In User Service) server must be implemented. RADIUS acts as an intermediary between the WLAN infrastructure and the LDAP directory, facilitating authentication requests. When a user attempts to connect to the WLAN, the access point forwards the authentication request to the RADIUS server, which then queries the LDAP directory to verify the user's credentials. This integration ensures centralized authentication and enhances security by leveraging existing directory services.

A Non-Disclosure Agreement (NDA) is a legal contract that establishes a confidential relationship between parties. In the context of WLAN design, it ensures that any proprietary information shared by the customer during the information-gathering phase remains confidential and is not disclosed to unauthorized parties.

Non Disclosure Agreements

The Statement of Work (SoW) outlines the tasks and deliverables of the project but does not address confidentiality.

The Bill of Materials (BoM) lists the required components for the project but does not pertain to information protection.

A Hold Harmless agreement typically pertains to liability and indemnification, not confidentiality.

The IEEE 802.11y amendment introduced support for operation in the 3.65–3.7 GHz frequency band, allowing for higher power transmissions up to 20 watts Equivalent Isotropically Radiated Power (EIRP).This enhancement was designed to improve wireless coverage and performance, especially in environments requiring extended range and penetration.

The increased power and frequency range provided by 802.11y facilitate better service in areas where traditional Wi-Fi bands may be congested or less effective.

Co-Channel Interference (CCI) occurs when multiple APs on the same channel are heard in the same area, even at relatively low signal levels. CCI is not eliminated simply because signals are below −75 dBm. In fact, CCI is a concern even when APs are heard at levels as low as −85 dBm or lower.

From CWDP-305:

“CCI can be problematic even when the signal from neighboring APs is heard at levels between −85 dBm to −93 dBm. Effective channel planning requires minimizing overlap of same-channel signals at or above these thresholds.”

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

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."

Target Wake Time (TWT) is a power-saving feature introduced in 802.11ax (Wi-Fi 6) that allows devices to negotiate specific times to wake up and communicate, reducing the need for constant listening and thereby conserving battery life. This feature is particularly beneficial for IoT devices and other battery-powered clients.

Comprehensive and Detailed Explanation:

The current WLAN setup with only two APs supporting over 300 client devices is insufficient and leads to performance degradation. Simply adding more APs without a proper design can cause co-channel interference and other issues. Upgrading Ethernet connections or increasing AP power does not address the core problem of inadequate design for high-density environments. The appropriate action is to redesign the WLAN specifically for the auditorium, considering factors such as client density, application requirements, and RF environment to ensure reliable and efficient Wi-Fi performance.

EAP-TLS (Extensible Authentication Protocol-Transport Layer Security) is considered one of the most secure EAP methods. It requires both the client and the server to have certificates, enabling mutual authentication. This method eliminates the need for passwords, reducing the risk of credential theft.

EAP-TTLS allows for server-side certificates and can use passwords for client authentication, making it less secure than EAP-TLS.

PEAP encapsulates EAP within a TLS tunnel, typically using server certificates and password-based client authentication.

Comprehensive and Detailed Explanation:

Mounting APs above the ceiling can significantly degrade WLAN performance due to signal attenuation caused by ceiling materials and obstructions. If aesthetic requirements were not communicated during the initial requirements gathering, the current deployment does not align with the documented design specifications. The appropriate course of action is to inform the stakeholder that the WLAN performance requirements may not be met under the current installation and that a new design process is necessary to address the aesthetic constraints while ensuring optimal performance.

Comprehensive and Detailed Explanation:

When troubleshooting 802.1X/EAP authentication issues, consider the following:

A.Ensure the RADIUS server is online and that the APs and WLAN controllers are configured to communicate with it on the correct port. Misconfigured ports can prevent authentication requests from reaching the server.

C.Verify that the authenticator (e.g., AP or controller) supports the EAP type configured on the client. A mismatch can lead to authentication failures.

D.If using certificate-based EAP methods (like EAP-TLS), confirm that the client's certificate is valid, not expired, and trusted by the RADIUS server. Certificate issues are common causes of authentication problems.

Note:

B.The RADIUS shared secret is configured between the authenticator and the RADIUS server, not on the client (supplicant). Therefore, this option is not applicable.

Comprehensive and Detailed Explanation:

A Wireless Network Management System (WNMS) is designed to monitor, configure, and manage wireless network components. It primarily interacts with theManagement Plane, which is responsible for:

Monitoring network performance.

Configuring network devices.

Managing firmware updates and policies.

This interaction allows administrators to oversee the network's health and make necessary adjustments to maintain optimal performance.

When designing a WLAN infrastructure, it's essential to calculate the Power over Ethernet (PoE) budget accurately to ensure all Access Points (APs) receive sufficient power. IEEE 802.3at, also known as PoE+, provides up to 30 watts of power per port. Therefore, for 6 APs:

6 APs × 30 W = 180 W

This calculation assumes that each AP requires the full 30 W provided by IEEE 802.3at and that there are no additional power losses or overheads. It's always a good practice to include a buffer in real-world scenarios to account for power losses in cables and potential future expansions.Quizlet

When designing a wireless bridge over a distance of 13 kilometers, it's crucial to account for the Earth's curvature, known as the "Earth bulge," which can obstruct the Fresnel Zone and degrade the signal.The Fresnel Zone is an elliptical area around the line of sight between two antennas, and any obstruction within this zone can cause signal diffraction and attenuation.

The CWDP-305 Official Study and Reference Guide highlights this consideration:

"For long-distance point-to-point links, the Earth’s curvature becomes a factor, and the Fresnel Zone must be clear of obstructions, including the Earth bulge, to maintain signal integrity."

Therefore, when planning such links, engineers must calculate the Fresnel Zone and ensure that the Earth bulge does not intrude into this zone, possibly requiring higher antenna placements or alternative solutions.

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 primary objective of the initial pre-deployment meeting is to communicate the design decisions to the deployment team, ensuring they understand the design documentation.This alignment is crucial for the successful implementation of the WLAN infrastructure as per the design specifications.

The CWDP-305 Official Study and Reference Guide highlights the importance of clear communication during the deployment phase.

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.

When deploying a WLAN that includes both WMM-PS (Wi-Fi Multimedia Power Save) certified devices and legacy devices that do not support WMM, it's important to understand the implications on performance and battery life.

WMM-PS, based on Unscheduled Automatic Power Save Delivery (U-APSD), allows client devices to conserve battery power by managing the time the device spends in sleep mode and reducing the need for frequent wake-ups.This mechanism is particularly beneficial for applications like VoIP, where timely delivery of packets is crucial.

However, legacy devices that do not support WMM-PS rely on older power-saving mechanisms, such as PS-Poll, which are less efficient.When both WMM-PS and non-WMM-PS devices operate on the same WLAN, the differences in power-saving capabilities can lead to inconsistencies in performance and battery life.Specifically, WMM-PS devices may experience better battery conservation and performance, while non-WMM-PS devices may have reduced efficiency.

This scenario is addressed in the CWDP-305 Official Study and Reference Guide, which emphasizes the importance of understanding client capabilities and their impact on WLAN performance.

The most accurate method to determine wall attenuation is to perform empirical measurements. First, measure the Received Signal Strength Indicator (RSSI) in free space at a known distance, such as 1 meter (3 feet). Then, place the access point 0.32 meters (1 foot) away from one side of the wall and the measuring device 0.67 meters (2 feet) away on the opposite side. By comparing the RSSI readings from the free space and through the wall, you can calculate the wall's attenuation. This method accounts for real-world variables and provides more accurate data than relying solely on predictive models or manufacturer specifications.

In environments like museums, aesthetic considerations are paramount. To maintain the visual integrity of exhibits while ensuring robust wireless coverage, APs can be concealed using plastic covers that match the surroundings. These covers are designed to be RF-transparent, ensuring that signal strength and quality are not compromised.

Other options are less suitable:

Locking the AP inside a metal box would severely attenuate the wireless signal due to the shielding effect of metal.

Placing APs between walls and I-beams may obstruct signal propagation and complicate maintenance.

Using outdated technology like 802.11b APs would not meet modern performance standards and could introduce compatibility issues.

The Physical Installation Guide is a document that offers step-by-step instructions for technicians on mounting and configuring access points. It includes details such as mounting locations, orientation, cabling requirements, and configuration settings. This guide ensures that APs are installed consistently and according to the design specifications, which is crucial for optimal network performance. Unlike the Statement of Work or Bill of Materials, which outline project scope and equipment lists respectively, the Physical Installation Guide focuses specifically on the practical aspects of AP deployment.

In public Wi-Fi environments, it's common to implement security measures that prevent clients from communicating directly with each other. This is achieved through peer-to-peer blocking, also known as client isolation. When enabled, this feature ensures that each client can communicate with the AP and access external networks but cannot interact with other clients on the same WLAN.

This setup enhances security by reducing the risk of attacks or unauthorized access between clients.

RTS/CTS is the best protection mechanism for backward compatibility of 802.11n devices with 802.11b devices because it prevents collisions and interference between different modulation types. 802.11n devices use OFDM, while 802.11b devices use DSSS. These two modulation types are not compatible with each other, but they can coexist in the same environment if they use protection mechanisms to avoid overlapping transmissions. RTS/CTS is a protection mechanism that requires a station to send a Request to Send (RTS) frame before transmitting data, and wait for a Clear to Send (CTS) frame from the receiver or the access point. The RTS and CTS frames are sent at a clause 15 (DSSS) or clause 18 (HR/DSSS) rate, which can be understood by both 802.11n and 802.11b devices. The RTS and CTS frames also contain a duration field that indicates how long the data transmission will last. This way, other stations can defer their transmissions until the channel is clear. RTS/CTS reduces the chances of collisions and hidden node problems, and improves the performance and reliability of the wireless network. References: CWNP, CWDP Certified Wireless Design Professional Official Study Guide, How 802.11n backward compatibility works

Comprehensive and Detailed Explanation:

Modulation is the technique of varying a carrier signal's properties—such as amplitude, frequency, or phase—to encode and transmit data. This process allows the transmission of information over various mediums, including radio frequencies used in wireless communications.

Option A:Describes spread spectrum techniques, not modulation.

Option B:Is a partial description but lacks the specificity of how the carrier is modified.

Option D:Is a vague statement that doesn't accurately define modulation.

When conducting a site survey, accurately determining ceiling heights is crucial for proper AP placement and coverage prediction.If ladder use is restricted, utilizing a laser distance meter provides a precise and cost-effective solution.Laser measures can quickly and safely determine vertical distances without the need for physical elevation.گروه آموزشی و پژوهشی سیب

The CWDP-305 Official Study and Reference Guide emphasizes:

"Laser distance meters are valuable tools during site surveys, allowing for accurate measurements of ceiling heights and other distances without the need for ladders or lifts."

Comprehensive and Detailed Explanation:

IEEE 802.3at, also known as PoE+, provides up to 30 watts of power per port. To calculate the minimum Power over Ethernet (PoE) budget required for 6 access points (APs):

30 W/AP × 6 APs = 180 W

Therefore, a switch must have a minimum PoE budget of180 wattsto support six 802.3at-powered APs.

A Non-Disclosure Agreement (NDA) is a legal contract that establishes a confidential relationship between parties.In the context of WLAN design, an NDA ensures that any proprietary or sensitive information shared by the customer during the information-gathering phase is kept confidential and not disclosed to unauthorized parties.This agreement builds trust between the service provider and the customer, facilitating open communication and information sharing necessary for effective WLAN design.

Band steering is a technique used to encourage dual-band clients to connect to the less congested 5 GHz band. However, some client devices are persistent and may not respond to steering attempts, continuing to probe only on the 2.4 GHz band. To ensure these clients can still connect to the network, band steering algorithms are designed to eventually allow association on the 2.4 GHz band after a certain number of ignored Probe Requests. This approach balances optimal network performance with client compatibility.

Extreme Networks Documentation

Comprehensive and Detailed Explanation:

WPA/WPA2-Personal is typically used in scenarios where:

A.Client devices lack support for 802.1X/EAP, making enterprise authentication methods unfeasible.

C.Devices are provisioned in bulk with shared credentials, simplifying deployment without the complexity of individual 802.1X configurations.

However:

B.High-latency roaming is undesirable; low-latency is preferred for seamless connectivity.

D.Requiring unique access credentials aligns more with WPA/WPA2-Enterprise, which supports individual authentication.

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:

An incorrect Frame Check Sequence (FCS) indicates that the frame was corrupted during transmission. This corruption can be due to various factors, but in the context of a WLAN, common causes include multipath interference and excessive collisions. Multipath occurs when RF signals reflect off surfaces and arrive at the receiver at different times, causing interference. Excessive collisions can happen in environments with high device density or overlapping coverage areas, leading to degraded performance.

Once the WLAN is validated and operational, the next step is knowledge transfer. Support staff must be trained on monitoring, troubleshooting, and configuration, while end-users benefit from understanding basic usage and policies. Executives and guests are not directly involved in daily operations.

From CWDP-305:

“Training should be delivered to IT support staff responsible for WLAN operations, and optionally to end-users for user-side clarity. This ensures ongoing support, proper use, and reduced downtime.”

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

Centralized data forwarding means all wireless traffic is tunneled back to a central controller, which handles tasks such as filtering, firewalling, and policy enforcement.

From CWDP-305:

“Centralized data forwarding enables consistent policy enforcement and traffic filtering by handling all traffic at the controller rather than at individual APs.”

This approach provides better control and visibility, especially in environments with strict security and traffic management requirements.

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

Web-based applicationsare designed to operate over the internet using web browsers. Each user interaction, such as clicking a link or submitting a form, typically results in multiple communications between the client and server. These interactions often involve the transfer of various resources, including HTML files, CSS stylesheets, JavaScript files, images, and other data.

This pattern of frequent back-and-forth communication can place significant demands on network resources, particularly in terms of bandwidth and latency. When designing WLANs to support web-based applications, it's essential to ensure sufficient capacity and performance to handle these demands effectively.