Certified Wireless Design Professional Questions and Answers
When performing an indoor predictive site survey to make the WLAN planning and design cycle more efficient, what is a best practice for configuration of the simulated APs in the predictive modeling software?
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What metric implements the simplest algorithm and lowest accuracy in networks requiring locations?
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What is the best method of gathering attenuation measurements from any building materials or objects?
What is the minimum PoE budget needed on a switch to support 6 (six) APs that can only be powered using IEEE 802.3at if no other details are
provided?
In an RSN requiring low-latency reassociations and no fast secure roaming protocols, what security solutions are ideal for protecting VoWiFi communication?(Choose all that apply.)
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If radar has reportedly been detected on your WLAN deployment, what bands would you consider avoiding?
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When using a predictive design tool, you have selected APs with an antenna gain 3 dBi and set the transmit power of the predicted APs to 25 mW.
What should be EIRP of the APs in the design?
A controller-based WLAN infrastructure has its controller on a different subnet than its APs. What device must be used to enable any
communication between the
Controller and the APs?
What are the two types of WLAN discovery/scanning?
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What is the most suitable antenna option to be used when designing a WLAN infrastructure with APs mounted on a ceiling with a height of more
than 20 feet and having all of the client stations used from the floor?
During your first pre-deployment meeting with the deployment team, you hand out the full design documentation to all of them. What's your
primary goal during this meeting?
ABC Manufacturing has a heavily-used dual-band (2.4 / 5 GHz) WLAN, but sporadic RF interference across the 2.4 GHz band is causing dropped
VoWiFi calls and leading to data connectivity and throughput problems.
In addition to avoiding 2.4 GHz channels and installing a distributed spectrum analyzer to locate RF interference sources, what should the
implementer do to resolve the problem fully?
One of your warehouse customers called you reporting problems with their WLAN in some locations that you designed and installed over a year ago. What should be one of your first considerations for your line of questioning?
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For an antenna 35 dBi of gain is needed. What antenna type should be used to achieve this gain?
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You're about to deploy an Enterprise-class VoWLAN infrastructure. You need to ensure that QoS is properly configured throughout the network.
What Access
Category (AC) should voice frames/packets use?
In 802.11, clients are required to be calibrated for RSSI and SNR reporting to:
ABC Company has a WLAN controller with 10 controller-based APs; the Voice SSID is configured for centralized data forwarding. Each AP is
connected to an access port on a layer-2 Ethernet switch. Each layer-2 switch is uplinked to a single layer-3 core Ethernet switch. The WLAN
controller is connected directly to the layer-3 core Ethernet switch. Layer-3 tunnels are created between all controller-based APs and the WLAN
controller. A voice server is connected to the layer-3
Ethernet switch.
When a voice-enabled QoS STA sends an IP data packet to a voice server in this scenario, the DSCP value carried in the STA's IP data packet gets
mapped to what and by which device?
You performed a site survey with two USB Wi-Fi adapters using a special driver written for the site survey software. After deployment, you realized
that the client devices used by your customer are getting lower RSSI values than that shown during your site survey. What is the most likely reason
for this result?
During a post-deployment verification, you are requested to troubleshoot an area where users are experiencing poor throughput. They are using
data communication only, mainly from laptops. You captured the frame showing an incorrect FCS. This frame is typical of those that were
captured by the analyzer.
What does this frame reveal about the RF network in this area?
To ensure that your design meets the requirements of the WLAN, what should be defined in your WLAN design software that will result in different requirements at varying locations on the floor plan1?
What document can be useful when determining client capabilities in a WLAN design project?
A museum wants to offer Wi-Fi to its visitors. One of their requirements is to have the APs blend into the design of the museum. What should you do to meet this requirement?
A museum wants to offer Wi-Fi to its visitors. One of their requirements is to have the APs blend into the design of the museum. What should you do to meet this requirement?
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In the enterprise, when is WPA/WPA2-Personal generally a recommended solution?(Choose all that apply.)
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A cable with 2.5 dB of loss is used to measure the return loss of an antenna. The measured value in-band is shown to be larger than 20 dB. What is the actual return loss of the antenna, and is it considered to be a reasonable value?
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You are using site software design features. You have imported a floor plan, but the simulated RF coverage is nowhere close to the real RF coverage you see with a walkabout.
Given that the simulation is significantly different, when step was likely missed when using the software?
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If the amplifier in Question 4 has a noise figure of 10 dB but a gain of 0 dB, what is the total noise figure of the cable, amplifier, and filter in series?
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The thermal noise is at −174 dBm/Hz. A spectrum analyzer has a resolution bandwidth of 1 kHz and a 5 dB noise figure. What is the level of the noise floor?
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In a multiple channel architecture (MCA) network supporting 802.1X authentication, what aspect of WLAN design affects client roaming efficiency
and effectiveness?
A business traveler from North America is in Europe. The hotel only provides coverage in 2.4 GHz. The traveler connects to the hotel's SSID and
notices an AP in the hotel room. However, the laptop reports a very low RSSI when connected. The traveler does not have the same problem when
connecting in the lobby. What would be the most likely cause of the low RSSI in the hotel room?
What is the chip rate of 1 Mbps 802.11b?
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Excessive uplink RTP frame retransmissions can result in ____________.
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What should always be done before connecting an AP to the production network?
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As a device starts to shift to lower PHY rates, what factors usually influence a device decision to shift to lower PHY rates?(Choose all that apply.)
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SSID hiding is not generally recommended because some frames require inclusion of the SSID. In what frames is the SSID always included?
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What is the purpose of defining wall materials in WLAN design software?
A bandpass filter has a maximum in-band loss of 1.5 dB, ripple of 0.4 dB, and a return loss of 15 dB. What is the minimum in-band loss?
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A wireless network with fewer APs at higher power levels to cover a large area is said to be which of the following?
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A WLAN that you designed has been deployed in one area, users ate complaining that the network performs poorly. When you analyze the area you see that a new interferer has been introduced that was not there during the pre-design survey You've been informed that the interferer cannot be removed as it is an essential loT device. What action do you recommend?
Which DHCP option, when required, should be configured and enabled to help APs locate their wireless LAN controller?
When deploying a new WLAN infrastructure using PoE to power the APs, you realize that a known good AP is not powering up. You use the same
cable to connect your laptop and connect without any trouble. What is the most likely reason the AP did not power up?
When implementing multiple SSIDs to what is each SSID typically mapped in order to provide traffic management separately for each SSID?
Which one of the following options would you consider a well-designed WLAN infrastructure when measuring RSSI Notse floor and SNR in a required area?
Low RSSI, Low Noise Floor Low SNR
High RSSI, Low Noise Floor High SNR
High RSSI, High Noise Floor Low SNR
Low RSSI, High Noise Floor Low SNR
After designing and deploying a WLAN infrastructure, you realized the CCI is causing poor performance in the 2.4 GHz band. Primarily, you've
designed the
WLAN for 5 GHz and 2.4 GHz as a best effort. You found out that the implementers didn't follow your guidelines when configuring the WLAN
infrastructure. What can you do to minimize as much as possible the CCI impact in the 2.4 GHz band?
In this question, you will compare the mobility processes of a network that supports WPA2-Personal and WPA2-Enterprise. Assume the use of a
15-character
ASCII passphrase for WPA2-Personal and EAP-TTLS/MSCHAPv2 with WPA2-Enterprise. Also, assume that proprietary roaming protocols are not
supported.
When a device transitions from one BSS to another within the same ESS, what step must be performed in the WPA2-Enterprise transition that are
not performed in the WPA2-Personal transition?
Given: A WLAN controller is connected to ABC Company's core layer 3 Ethernet switch with an IEEE 802.1Q trunk connection. The WLAN
controller's native
VLAN is VLAN 6 and its IP address is 10.0.14.2 /24. Lightweight APs supporting centralized forwarding are connected to the network on VLANs 7,
8, and 9, and they each build a Layer 3 tunnel back to the WLAN controller's IP address.
The dynamically assigned IP addresses received by each AP from a DHCP server will be ________________.
Given: In a site survey deliverable report, you are expected to explain the spectrum measurements taken at the customers site. What portion of a
spectrum analyzer view can be used to determine if a given channel is too active for use as the active channel for a new AP?
What is a valid 40 MHz channel configuration in the 2.4 GHz ISM band where channels 1-11 are permitted?
A museum wants to offer Wi-Fi to its visitors. One of their requirements is to have the APs blend into the design of the museum. What should you
do to meet this requirement?
What is the minimum PoE budget needed on a switch to support 6 (six) APs that can only be powered using IEEE 802.3at if no other details are provided?
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What is the most appropriate antenna which will require the least Intentional Radiator power for a point-to-point bridge link spanning 1200 meters?
How are EAP messages transported over 802.11 wireless LANS?
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Given: For this fill-in the blank question, each answer option contains an answer for the first and second blanks, separated by a dash "—". Choose
the answer option that correctly fills in both blanks in the following sentence.
A WLAN may use 802.11 admission control to ________, and admission control requirements are configured separately for each ________.
iPerf is a tool used in site surveys and validation surveys for what purpose?
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During the deployment of a WLAN the customer complains that the chosen locations for several APs are ruining the aesthetics of the building Instead of changing AP locations and requiring a redesign, what action can you recommend1?
Using a SCA means that all APs will be using the same channel in a given layer. How is the AP with which the client associates determined?
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When deploying long-distance 802.11 bridge links (10 miles / 16 km), what parameter may be critical for improving data flow by reducing retries
caused by the long distances?
Which of the following items could be considered constraints when performing a network design?(Choose all that apply.)
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Your customer is using PSK as their only authentication. They have an industry requirement to move to a stronger solution. Your recommendation
is to move to a certificate-based type of authentication where both the client and server require certificates. Which EAP type would be the best fit?
What functions may be performed by a WIPS?(Choose all that apply.)
During lunch time in the break room of a company, Wi-Fi connectivity on the 2.4 GHz band is intermittent. Every other time of the day, it works fine.
What's the likely cause of this issue?
Before performing a pre-deployment passive RF survey of a new deployment using survey mapping software, which of the following must be performed?
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What statements are true regarding jitter and latency?(Choose all that apply.)
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What is an advantage of centralized data forwarding?
You are conducting a physical site survey where heavy machinery is repaired. What is a common item required specifically for this type of survey?
What is the DSCP Per Hop Behavior equivalent classification of the 802.11 AC_VO priority level?
You have performed a validation site survey after deploying a WLAN infrastructure that is an All-Wireless-Office. One specific application of your
customer is experiencing delay when using the application after moving from wired connectivity. After your validation, you realized that all APs are
using 80 MHz channel- widths instead of 20 MHz on the 5 GHz band, as it was designed. What can be done to resolve the delay on this
application?
A customer is acquiring a new VoWLAN system to replace their existing wired phone system. When reading about his system's requirements, you
learned that is requires 25 db of SNR to work as expected. After surveying the environment, you discovered that the noise floor is -88 dBm. What
should be the minimum RSSI value to meet the system's requirements?
When creating a long-distance bridge link, it is important to know the channels in use by other networks on both ends of the link and within a reasonable range It is not as Important to know the channels in use in the middle area of the link. Why is this the case?
You are site surveying a network for VoWiFi. You have positioned an AP for a manual survey and are moving away from the AP with a phone in
Survey Mode in your hand and you are reading the RSSI value of the signal received from the AP. You have previously determined that the noise
floor was approximately -94 dBm on this floor of the building. The phones documentation does not specify a recommended RSSI or SNR value for
best performance.
Based on the information provided and the type of device (VoWiFi phone) you are deploying, what minimum RSSI should you plan for in all areas
you are monitoring and where VoWiFi service is desired?
During a validation site survey, you realize that the installers mounted some of the APs on the wait when the design called Tor a celling mount. They said that this was done because the cabling company did not have the right tools to run the cables above the ceiling. You know that this will cause a difference in how the Wi-Fi signal will radiate throughout the environment. What should you do in this case?
What is the purpose of Friis transmission equation [ (LdB) = 20 log(d) + 20 log (f) - 27.55 ]?
You are designing a WLAN and nave been asked to recommend a security solution for the network The organization requires that 802 1X/EAP be implemented, but they do not have a PKI and do not wish to deploy one They suggest that mostly Windows clients. Apple phones and Android phones will be used What do you recommend?
You and 10 other people are connected to a public hot-spot. You issue a ping sweep on the network, but you can't find any devices on the same
subnet as yours.
What feature might be enabled on the WLAN infrastructure that is preventing you from communicating with other devices on that subnet?
An engineering firm just upgraded their WLAN form nine 802.11n APS to nine 802.11ac APs. After this upgrade, they did not see any improvement in throughput. What is the most likely cause of this result?
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What advantages are provided by per-user PSKs when compared with ESS-wide PSKs?(Choose all that apply.)
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What document is typically created to launch a project?
What are some significant drawbacks that are present with WPA/WPA2-Enterprise that are not present with WPA/WPA2-Personal?(Choose all that apply.)
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What important item is often left out of operational and maintenance plans?
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You are being asked to design a WLAN for a number of WLAN clients that will use Telnet as the primary application. The customer has asked that you use only the number of APs necessary because of the complex installation and construction costs each AP installation will incur in this particular environment.
What design factors do you consider?
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What single tool, by design can be used to verify channel selection, encryption in use and number of APs above a specified signal threshold in a given location during deployment?
When selecting a centralized WLAN architecture, what new problem may arise when you change the data forwarding model from centralized to
distributed?
What document is typically created to launch a project?
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As you plan a WLAN upgrade, you have assessed the network requirements and data signatures of your applications. One of the popular
applications used on your network requires high bandwidth and low to medium Wi-Fi loss, but can tolerate moderate latency and jitter.
What application matches this description?
