CWNA-106 - Certified Wireless Network Administrator
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A WLAN transmitter that emits a 200 mW signal is connected to a cable with 3 dB loss. If the cable is connected to an antenna with 10 dBi gain, what is the EIRP at the antenna element?
For what likely reasons might an organization choose to purchase an AP designed for outdoor deployment to use as an indoor WLAN AP at an industrial facility? (Choose 2)
Physical security and theft prevention
Protection from environmental conditions
The IEEE 802.11a/n/ac physical layer technologies utilize the 5 GHz frequency band. What is true of the channels in this frequency spectrum?
DFS may be required in some regulatory domains on some channels.
When performing a site survey for a Multiple Channel Architecture (MCA) system in a multi-tenant building with five floors, what aspect should you, as the site surveyor, keep in mind?
The channel reuse pattern should be three dimensional with the RF cell extending coverage of each access point to other floors.
What features are most often configurable within 802.11 WLAN client utilities? (Choose 2)
What is an advantage of using WPA2-Personal instead of WEP-128 as a security solution for 802.11 networks?
WPA2-Personal uses dynamic encryption keys, and WEP-128 uses static keys.
ABC Company is planning to install a new 802.11ac WLAN, but wants to upgrade its wired infrastructure first to provide the best user experience possible. ABC Company has hired you to perform the RF site survey. During the interview with the network manager, you are told that the new Ethernet edge switches will support VoIP phones and 802.11 access points, both using 802.3 PoE. After hearing this information, what immediate concerns do you note?
The power budget in the edge switches must be carefully planned and monitored based on the number of supported PoE devices.
When using an RF splitter to connect one transceiver to sector antennas loss is incurred. What is this loss called?
What item is essential for performing a manual RF site survey for a warehouse facility?
A facility map with an explanation of applications used in each area
When compared with legacy Power Save mode, how does VHT TXOP power save improve battery life for devices on a WLAN?
VHT TXOP power save uses the partial AID in the preamble to allow clients to identify frames targeted for them.
ABC Company performs government contract work that requires disabling WLANs and has recently purchased an 802.11 Wireless Intrusion Prevention System (WIPS) to enforce their "NO WIRELESS" network security policy. What attack type cannot be recognized by the WIPS?
You are implementing a VHT-capable AP. Which one of the following channels is available in the 802.11ac amendment to the 802.11-2012 standard, which was not available in the standard before this amendment?
You have been sent as a consultant to a customer site that is experiencing problems with some 2.4 GHz clients on their 802.11a/g/n/ac network. After collecting information from the company about the problem, your initial troubleshooting step is to find a client device experiencing performance problems and observe its 802.11 frame exchanges in a protocol analyzer. The retransmission rate for that client is 65% instead of the company's baseline, which is 9%. Based on this information, what troubleshooting step should follow to isolate the problem?
Evaluate the client's operating frequency band with a spectrum analyzer, looking for a high noise floor or interference sources.
What advantages does using predictive site survey modeling software offer over performing a manual site survey? (Choose 2)
Predictive modeling software makes it simple to assess multiple different AP locations and then adjust and display the AP's expected coverage pattern in almost real-time.
It takes less time to create an initial site survey for a large facility when using predictive modeling software than when performing a manual survey.
What word describes the bending of an RF signal as it passes through a medium of a varying density from that of free space?
Return Loss is the decrease of forward energy in a system when some of the power is being reflected back toward the transmitter. What will cause high return loss in an RF transmission system, including the radio, cables, connectors and antenna?
An impedance mismatch between components in the RF system
You are being interviewed by ABC Company for employment as a wireless site survey expert. The interviewing manager asks you what items should be included in a site survey report generated as part of a manual site survey process. What answer would be accurate? (Choose 2)
RF heat map illustrating coverage and signal quality for each frequency band
Documentation noting where each access point will be placed and how it will be mounted
What phrase defines Equivalent Isotropically Radiated Power (EIRP)?
The highest RF signal strength that is transmitted from a given antenna
When replacing the antenna of a WLAN device with a similar antenna type that has a higher passive gain, what antenna characteristic will decrease?
What factors will have the most significant impact on the amount of wireless bandwidth available to each station within a BSS? (Choose 2)
The number of client stations associated to the BSS
The data rates at which nearby client stations are transmitting and receiving data
What is the intended use for the WLAN hardware known as a pole or mast mount unit?
Mounting an omnidirectional antenna to a mast
What statements about the beamwidth of an RF antenna are true? (Choose 2)
Horizontal and vertical beamwidth are calculated at the points in which the main lobe decreases power by 3 dB.
Horizontal beamwidth is displayed (in degrees) on the antenna's Azimuth Chart.
ABC Hospital is planning a Wi-Fi infrastructure upgrade where the 802.11b/g APs (HR/DSSS and ERP) would be replaced with new dual-radio 802.11n/802.11ac (HT and VHT) APs. ABC wants to minimize the time and cost associated with performing a new site survey, so they will be mounting all of the new APs in the same locations and with the same cable drops as the existing APs. What is one performance drawback with this deployment method?
The existing WLAN plan, including the AP locations, may not provide the benefits seen in HT and VHT 802.11 PHY capabilities.
When planning an access point deployment that utilizes Power over Ethernet (PoE) switches at the network edge, what design decision could adversely affect the operation of 802.3-2012, Clause 33 APs?
All ports on the Ethernet switch will be supporting Class 3 PoE powered devices.
XYZ Company has hired you to perform an indoor site survey of their 5-story facility. They own the building and rents out unused floors (floors 2 and 4) to other companies, and the other companies already use 802.11 WLANs. XYZ Company wants all of the offices they occupy to be surveyed as part of the project. What actions should be recommended as part of the site survey project? (Choose 2)
Determine how much signal strength is passing between floors.
Locate wiring closets on each floor occupied by XYZ Company.
In addition to throughput enhancements, what other improvements does a dual-band 802.11ac AP provide when compared with 802.11a/g APs? (Choose 2)
Better link reliability between 802.11a/b/g client devices and 802.11ac APs
Improves service quality for real-time applications at greater distances
Prior to association, what parameter can 802.11 client devices measure and use to select the optimal access point for association?
Signal strength of access point beacons received
A Wi-Fi Alliance interoperability certificate indicates that a device is a/b/g/n certified. It further indicates one transmit and receive spatial stream for both the 2.4 GHz and 5.0 GHz bands. It further indicates support for both WPA and WPA2 Enterprise and Personal. Finally, it indicates support for EAP-TLS, EAP-TTLS/MSCHAPv2, PEAPv0/EAP-MSCHAPv2 and PEAPv1/EAP-GTC. Which one of the following statements is false?
300 Mbps is the maximum supported data rate for this device.
What statement about 802.11 WLAN performance is true?
Use of larger frame sizes results in greater throughput in low interference environments.
An 802.11 WLAN transmitter that emits a 50 mW signal is connected to a cable with 3 dB of loss. The cable is connected to an antenna with 16 dBi of gain. What is the EIRP power output?
What factors are likely to cause the greatest impact on the application layer throughput of an 802.11n client station in a 2.4 GHz HT BSS? (Choose 3)
Use of WEP or TKIP for encryption instead of CCMP
RF interference from more than 10 nearby Bluetooth transmitters
Increasing or decreasing the number of spatial streams in use by the client station and AP
In a single channel architecture (SCA) WLAN system, 802.11n (HT) APs should not share an SSID with 802.11g (ERP) APs. What is the reason for this recommendation?
Client stations would see two different sets of AP capabilities as they roam between APs with the same BSSID.
Lynne runs a small hotel, and as a value added service for her customers she has implemented a Wi-Fi hot-spot. Lynne has read news articles about how hackers wait at hot-spots trying to take advantage of unsuspecting users. She wants to avoid this problem at her hotel. What is an efficient and practical step that Lynne can take to decrease the likelihood of active attacks on her customers' wireless computers?
Enable station-to-station traffic blocking by the access points in the hotel
What mechanisms are specified by the IEEE 802.11 standard to attempt to prevent multiple radios from transmitting on the RF medium at a given point in time? (Choose 3)
Random backoff timer
Clear channel assessment
Network allocation vector
AP-1 is a 3x3:2 AP. STA-3 is a 3x3:3 client. What is the maximum number of spatial streams that can be used for a downlink HT-OFDM transmission from AP-1 to STA-3?
Two spatial streams, because the definition of the AP indicates that it is capable of only two spatial streams.
What term correctly completes the following sentence? In an IEEE 802.11 frame, the IP packet is considered by the MAC layer to be a(n) _________.
MAC Service Data Unit (MSDU)
What statements describe industry practices for communication protocols between WLAN controllers and controller-based APs? (Choose 2)
Some vendors use proprietary protocols, and some vendors use protocols based on public standards like RFCs.
All vendors support at least one L2 or L3 broadcast protocol for controller discovery by controller-based APs.
In an 802.11n WLAN with a heterogeneous set of associated client devices including 802.11b, 11g, and 11n, what HT protection mode will the BSS use?
Mode 3: Non-HT mixed mode
Which answer correctly completes the following sentence? The WMM certification, created by the Wi-Fi Alliance, is based on the ___________ coordination function with support for ___________ QoS priority.
What HT technology requires MIMO support on both the transmitter and receiver?
You are an independent contractor, hired to perform an indoor site survey and network design for Luxury Full Service Hotels International. The network will support hotel staff and guest users. You are interviewing the network manager to determine business, performance, and security requirements for the future 802.11 WLAN. What questions should you ask the IT manager? (Choose 2)
What data cabling is currently installed in the rooms and throughout the hotel?
What types of applications will be used by the hotel staff?
In an enterprise WLAN, what condition will prevent a dual-band VHT/HT client device from performing a fast and seamless transition (i.e. latency-sensitive applications are not disrupted) between two access points that are managed by the same WLAN controller?
The SSID of the current AP does not match the SSID of the new AP.
How is throughput capacity scaled in a single channel architecture (SCA) WLAN system?
By adding non-overlapping channel layers through the addition of more APs.
In a Wi-Fi client configuration utility, what feature is most likely to be user configurable?
EAP Authentication Type
What problems may exist for a multiple channel architecture (MCA) WLAN when its APs are all operating at full power (typically 100mW)? (Choose 2)
Wi-Fi enabled voice handsets with low transmit power can experience asynchronous downlink and uplink performance.
Cell size may be too large, causing co-channel interference to adjacent cells and reducing system capacity.
What facts are true regarding controllers and APs in a Split MAC architecture? (Choose 2)
An IP tunnel is established between the AP and controller for AP management and control functions.
In a distributed data forwarding model, the AP handles frame encryption and decryption.
You are the network administrator for ABC Company. Your manager has recently attended a wireless security seminar. The seminar speaker taught that a wireless network could be hidden from potential intruders if you disabled the broadcasting of the SSID in Beacons and configured the access points not to respond to Probe Request frames that have a null SSID field. Your manager suggests implementing these security practices. What response should you give to this suggestion? (Choose 2)
Any 802.11 protocol analyzer can see the SSID in clear text in frames other than Beacons and Probe Response frames. This negates any security benefit of trying to hide the SSID in Beacons and Probe Response frames.
Although it does not benefit the security posture, hiding the SSID in Beacons and Probe Response frames can be helpful for preventing some users (such as guests) from attempting to connect to the corporate network.
If an 802.11 RF transmission reaches a receiving antenna simultaneously by direct and reflected paths, what effect will the reflected signal have on the signal that took the direct line-of-sight path?
The signals will be distorted if the indirect signal arrives simultaneously at the receiver, but 90 degrees out-of-phase.
What problems may occur when there are hidden nodes in the BSS?
High retransmission count for a subset of client stations
A company has hired you to perform a pre-deployment site survey of their facility. During an interview, the network manager informs you that the new wireless network must use 5 GHz bands and OFDM, and VoWiFi handsets will be used extensively over the wireless network. What items do you need to include in the RF site survey report? (Choose 2)
A heat map demonstrating signal quality in areas where VoWiFi is supported.
Test results from an active survey with a VoWiFi handset