CWNA

Q. Which of the following frequency ranges are specified for use by IEEE 802.11 radios?

* 2.400 - 2.4835 GHz * 5.15 - 5.25 GHz * 5.470 - 5.725 GHz * 5.725 - 5.875 GHz

Q. What are two channel modes specified by the 802.11n (High Throughput) PHY?

* 20 MHz * 20/40 MHz

Q. XYZ Company has decided to install an 802.11 WLAN system that will support 1000 wireless users, but they are concerned about network security. XYZ is interested in deploying standardized security features. In addition to WPA2-Enterprise with PEAP and role-based access control, XYZ would like to support management frame protection as well as a fast secure roaming protocol for future mobile handsets. As XYZ Company selects a product to deploy, what two IEEE amendments, which are included in 802.11-2012, should be supported to provide the management frame protection and fast secure roaming security features?

* 802.11w * 802.11w

Q. What is a common feature of an 802.11 WLAN client utility?

* AP Signal strength meter * Link statistics display

Q. 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?

* 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.

Q. In addition to throughput enhancements, what other improvements does a dual-band 802.11ac AP provide when compared with 802.11a/g APs?

* Better link reliability between 802.11a/b/g client devices and 802.11ac APs * Improves services quality for real-time applications at greater distances

Q. Which features are incorporated in the 802.11-2012 specification and are recommend for robust WLAN client security?

* CCMP cipher suite * 802.1X/EAP

Q. What problems may exist for a multiple channel architecture (MCA) WLAN when its APs are all operating at full power (typically 100mW)?

* Cell size may be too large, causing co-channel interference to adjacent cells and reducing system capacity. *Wi-Fi enabled voice handsets with low transmit power can experience asynchronous downlink and uplink performance.

Q. Which antenna types are commonly used by indoor Wi-Fi devices in a MIMO diversity implementation?

* Dipole * Patch

Q. Which IEEE 802.11 physical layer (PHY) specifications include support for and compatibility of both OFDM and HR/DSSS?

* ERP (802.11g) * HT (802.11n)

Q. The IEEE 802.11-2012 standard requires VHT capable devices to be backward compatible with devices using which other 802.11 physical layer specifications (PHYs)?

* HT * OFDM

Q. What information is transmitted in the Beacon management frames of an HT access point to communicate about backward compatibility with ERP and HR/DSSS stations?

* HT Protection mode * Non-ERP Present field

Q. What statements about the beamwidth of an RF antenna are true?

* Horizontal and vertical beamwidth are calculated at the points in which the main lobe decreases power by 3dB. * Horizontal beamwidth is displayed (in degrees) on the antennas's Azimuth Chart.

Q. You are selecting antennas for a WLAN operating in the 5 GHz frequency band. What specifications should be evaluated for an antenna before it is implemented in this WLAN system?

* Impedance in Ohms * Elevation Beamwidth *Operating Frequencies

Q. What feature(s) are most likely to be supported by 802.11 enterprise-class WLAN controllers?

* Link Aggregation / port trunking * 802.1p and DSCP QoS * Captive web portals * IGMP snooping

Q. What WLAN system feature is required to produce a scenario with the following configuration on a single access point? 1. SSID = Guest / BSSID = AA:AA:AA:AA:AA:AA / VLAN = 22 / Subnet = 192.168.22.0 / RF Channel = 6 2. SSID = Corporate / BSSID = BB:BB:BB:BB:BB:BB / VLAN = 33 / Subnet = 192.168.33.0 / RF Channel = 6 / User Type A 3. SSID = Corporate / BSSID = BB:BB:BB:BB:BB:BB / VLAN = 44 / Subnet = 192.168.44.0 / RF Channel = 6 / User Type B

* Multiple WLAN Profiles *User-based authentication

Q. What causes of hidden nodes within a BSS would be more likely lead to an increase in collisions and retries?

* Obstacles between client stations causing attenuation * Large 802.11 cells with physically distributed stations

Q. The OSI model is a 7-layer model for understanding the functions of a communication system. What OSI sublayers are specifically addressed by the IEEE 802.11-2012 standard?

* PLCP * MAC

Q. 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?

* Physical security and theft prevention * Protection from environmental conditions

Q. What features are most often configurable within 802.11 WLAN client utilities?

* Power management * Roaming aggressiveness

Q. What statements accurately describe the RF cables and connectors that are used in an 802.11 WLAN system?

* RF cables have upper and lower frequency range specifications * Two RF connectors of the same type manufactured by different companies, may vary in specifications *every RF connector causes insertion loss

Q. 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?

* Random backoff timer * Clear channel assessment * network allocation vector

Q. What three cipher suites are specified by the IEEE 802.11-2012 standard?

* Temporal Key Integrity Protocol * Wired Equivalent Privacy * Counter Mode with CBC-MAC Protocol

Q. Two co-located 802.11b/g/n APs can interfere with one another and cause contention and collisions, even when the two APs are operating on non-overlapping channels (e.g. 1 & 6). What deployment flaw could cause this problem?

* The access points are mounted too closely to one another * The output power on the access points is too high.

Q. When a client moves to a new BSS within an ESS, what steps are part of the 802.11 reassociation process?

* The new access point transmits a Reassociation Response to the client station with a status value. * the client and new access point create unicast encryption keys

Q. What statements about the SSID are true?

* TheSSID must be included in an association request fram

Q. Why is it recommended for a wireless network administrator to disable 1 Mbps and 2 Mbps data rates on the WLAN infrastructure?

* To improve capacity in the BSS * To reduce the size of the AP's effective service area

Q. What features were introduced in the IEEE 802.11h amendment in order to uphold regulatory requirements for 5 GHz operation?

* Transmit Power Control (TPC) * Dynamic Frequency Selection (DFS)

Q. When designing a WLAN infrastructure implementation for high client density at a public venue such as a conference or stadium, what are common best practices?

* Use directional antennas to isolate the RF propagation * Implement a band steering feature for dual-band clients

Q. 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?

* 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.

Q. What answers correctly complete the following sentence? ____________ and ____________ carrier sense functions are used to determine if the wireless medium is busy.

* Virtual * Physical

Q. What facts are true regarding controllers and APs in a Split MAC architecture?

* an IP tunnel is

Q. In an 802.11 2.4 GHz system, what 22 MHz channels are considered non-overlapping?

* channels 5 and 10 * channels 2 and 8

Q. What factors are taken into account when calculating the link budget of a point-to-point outdoor WLAN bridge link?

* operating frequency * transmit antenna gain * transmit power

Q. In an 802.11n 2.4 GHz BSS, what prevents each station from using the full network bandwidth (e.g. 130 Mbps) for user data throughput when multiple clients are actively exchanging data with the AP?

* the DCF and EDCA coordination functions require backoff algorithms * WLAN devices cannot detect collisions and must receive positive frame acknowledgements

Q. What factors will have the most significant impact on the amount of wireless bandwidth available to each station within a BSS?

* the number of client stations associated to the BSS * the data rate at which nearby client stations are transmitting and receiving data

Q. ABC Company has thousands of Wi-Fi users accessing their network on a daily basis. TheirWLAN consists of 700 access points, 6 WLAN controllers, and a wireless network management system. What network functions are performed by the enterprise-class WNMS?

*RF pre-deployment planning and post-deployment reporting of access point locations on a floor plan. * Performance and security monitoring of WLAN controllers with alarms and notifications for administrative staff *Management of WLAN controller configuration and provisioning of firmware updates

Q. What factors influence the distance that an RF signal can be effectively received?

*Receiving station's radio sensitivity *Free Space Path Loss *Transmitting station's output power

Q. What statements describe industry practices for communication protocols between WLAN controllers and controller-based APs?

*Some vendors use proprietary protocols, and some vendors use protocols based on public tandards like RFCs *All vendors support at least one L2 or L3 broadcast protocol for controller discovery by controllerbased APs.

Q. An 802.11 WLAN transmitter that emits a 50mW signal is connected to a cable with 3dB of loss. The cable is connected to an antenna with 16 dBi of gain What is the EIRP power output?

1000mW

Q. Which data rate is supported by 802.11g radios that is not supported by 802.11a radios?

11 Mbps

Q. 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?

144

Q. The center frequency of channel 1 in the 2.4 GHz band is 2.412 GHz (2412 MHz). What is the center frequency of channel 4?

2.427 GHz

Q. 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

Q. A WLAN transmitter that emits a 200mW signal is connected to a cable with 3dB loss. If the cable is connected to and antenna with a 10dBi gain, what is the EIRP at the antenna element?

30dBm

Q. What statement about the IEEE 802.11e QoS facility is true?

802.11 QoS is achieved by giving high priority queues a statistical advantage at winning contention.

Q. What statement is true concerning the use of Orthogonal Frequency Division Multiplexing (OFDM) in IEEE 802.11 WLANs

802.111ac VHTOFDM utilized 256-QAM, which increases the data rate significantly over 64-QAM available in HT-OFDM

Q. As a consultant, you've been hired by XYZ Company to provide recommendations about client device selection, operation, and interoperability. What information should be considered to help them choose the right WLAN client devices?

802.11ac devices support the feature of the VHT PHY only in the 5GHz frequency band.

Q. What is always required to establish a high quality 2.4GHz RF link at a distance of 3 miles (5kilometers)?

A Fresnel Zone that is at least 60% clear of obstructions

Q. In an infrastructure Basic Service Set (BSS), how does the passive scanning process occur?

Access points broadcast Beacons on a single channel for which they are programmed. Nearby client stations listen for Beacons frames and record information found in the Beacons for use in the association process.

Q. 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

Q. When using WMM Power Save operation, a wireless client device _______________________________.

Alternates between awake and dozing, depending on its need to transmit and receive information

Q. Return Loss is the decrease of forward energy in a system when some of the power is being reflected back toward the transmitter.

Am impedance mismatch between components in the RF system

Q. What distinguishes an independent basic service set (IBSS) from an infrastructure basic service set (BSS)?

An IBSS does not have a distribution system (DS), but a BSS does

Q. What can cause an excessively high VSWR (voltage standing wave ratio)in a WLAN RF transmission line?

An impedance mismatch in the RF cables and connectors

Q. ABC Company has just purchased a 6 dBi patch antenna. After performing some tests with the 6 dBi antenna, they have concluded that more antenna gain is needed to cover their outdoor courtyard. When choosing an antenna with higher gain, what other antenna characteristic will also always change?

Beamwidth

Q. When replacing the antenna of a WLAN device with a similar antenna type that has a higher passive gain, what antenna characteristic will decrease?

Beamwidth

Q. 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.

Q. 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.

Q. As defined in the 802.11 specification, legacy Power Save requires an inefficient back-and-forth frame exchange process. Due to this inefficiency, many WLAN device implementations use a variation of 802.11 Power Save to accomplish the same function. What non-standard power save behavior is used by most Wi-Fi devices in actual legacy Power Save implementations?

Clients send null data frames to the AP and switch the power management bit from 1 to 0 receive queued data.

Q. The 802.11 protocol specifies a fundamental channel access method that is required for all stations and is used in all IBSS and BSS networks. What is this fundamental channel access method called?

DCF

Q. 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

Q. As a station moves away from the access point to which it is associated, it changes its data rate from 600 Mbps to 540 Mbps and then to 450 Mbps. What IEEE 802.11 term is used to describe this functionality?

Dynamic Rate Switching

Q. In a Wi-Fi client configuration utility, what feature is most likely to be user configurable?

EAP Authentication Type

Q. When a client station sends a broadcast probe request frame with a wildcard SSID, how do APs respond?

Each AP responds in turn after preparing a probe response and winning contention

Q. 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

Q. 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.

Q. In a long-distance RF link, what statement about Fade Margin is true?

Fade Margin is an additional pad of signal strength designed into the RF system to compensate for unpredictable signal fade.

Q. What problems may occur when there are hidden nodes in the BSS?

High retransmission count for a subset of client stations

Q. 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.

Hybrid, contention -based

Q. As an RF wave propagates through space, the wave front experiences natural expansion that reduces its signal strength in an area. what term describes the rate at which this expansion happens?

Inverse square law

Q. 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

Q. What type of device often causes interference across 50% or more of the 2.4 GHz frequency band?

Microwave oven

Q. 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

Q. What is the intended use for the WLAN hardware known as a pole or mast mount unit?

Mounting an omnidirectional antenna to a mast

Q. What term describes the effect of increasing the intensity of an RF wave with an antenna by focusing the energy in a specific direction?

Passive Gain

Q. To ease user complexity, your company has implemented a single SSID for all employees. However, the network administrator needs a way to control the network resources that can be accessed by each employee based on their department. What WLAN feature would allow the network administrator to accomplish this task?

RBAC

Q. What component of the 802.11 standard allows stations to reserve access to the RF medium for a specified period of time?

RTS or CTS frames

Q. what word describes the bending of an RF signal as it passes through a medium of a varying density from that of free space

Refraction

Q. 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

Q. What HT technology requires MIMO support on both the transmitter and receiver?

Spatial multiplexing

Q. What term correctly completes the following sentence? 802.11a/b/g used a mandatory 800ns guard interval. 802.11n introduced an optional short 400ns guard interval. Guard intervals (GI) are necessary in OFDM to reduce the likelihood of interference between two consecutive ____________.

Symbols

Q. The client devices that connect to your network include a mix of dual-band 802.11n and 802.11ac, single-band 802.11b/g/n, and some 802.11a/g/n. Your access points are configured with the same SSID on both the 2.4 and 5 GHz bands. The APs are also configured to prioritize client connectivity to 5 GHz. How does an AP perform band steering to encourage clients to use 5 GHz?

The AP may ignore the intial probe request or 802.11 authentication request sent in the 2.4GHZ band by dual-band clients

Q. XYZ Corporation is experiencing connectivity problems with their existing building-to-building bridge link. A concrete wall on the roof of one building is partially blocking the Fresnel Zone, and the connection is dropping many frames. The administrator moves the antenna to an area not obstructed by the concrete wall and then realizes the RF cable cannot reach the new location. If an extension cable is added to move the antenna, what are the likely results?

The Equivalent Isotropic Radiated Power (EIRP) will decrease.

Q. 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.

Q. As XYZ Company's wireless specialist, you have been asked to troubleshoot some unexpected frame patterns in a wireless protocol capture. Your peers explain that the network's beacon frames are inconsistent. That is, the BSSID is the same for all beacons, but the source address varies between three different addresses. What network configuration would cause this beacon frame behavior?

The beacons are from an IBSS instead of a BSS

Q. During the discovery and connectivity process, client and AP stations exchange information about their supported data rates. After the association, how do client and AP stations select the supported data rate that will be used to send an 802.11 data frame?

The client and AP each choose the optimal data rate to use independently of one another, based on their own measurements related to the RF link.

Q. 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.

Q. What phrase defines Equivalent Isotropic Radiated Power (EIRP)?

The highest RF signal strength that is transmitted from a given antenna

Q. ABC Company is planning a point-to-multipoint outdoor bridge deployment with standalone (autonomous) 802.11 bridge units. 802.1X/EAP will be used for bridge authentication. A Linuxbased RADIUS server will be used for authentication. What device in the bridge implementation acts as the 802.1X Authenticator?

The root bridge

Q. 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.

Q. ABC Company has a 2.4 and 5 GHz WLAN deployment. DFS functionality is enabled as required by the regulatory domain and APs use DFS channels as long as radar is not detected. Band steering is also enabled to encourage dual-band clients to use frequency bands with more capacity. Your performance analysis shows that many dual-band VoWiFi client devices will move back and forth between 2.4 and 5 GHz as the users roam throughout the building. All APs have 2.4 and 5 GHz radios enabled with transmit power adjusted to accommodate relatively similar cell sizes. This "band hopping" behavior is viewed by network staff to be undesirable. What is the most likely cause of the unpredictable client band selection behavior?

The voice client does not support DFS, and therefore experiences some 5 GHz coverage holes as it moves through the network.

Q. When using an RF splitter to connect one transceiver to sector antennas loss is incurred. What is this loss called?

Through loss

Q. 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.

Q. What statement about 802.3-2012, Clause 33 Power over Ethernet is true?

Up to 30 watts of power may be provided through an Ethernet cable

Q. What statement about 802.11 WLAN performance is true?

Use of large frame sizes results in greater throughput in low interference environments

Q. 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

Q. You are using a tool that allows you to see signal strength for all APs in the area with a visual representation. It shows you SSIDs available and the security settings for each SSID. It allows you to filter by frequency band to see only 2.4 GHz networks or only 5 GHz networks. No additional features are available. What kind of application is described?

WLAN discovery tool

Q. As a consultant, you have been hired by ABC Company to implement an outdoor WLAN connection between two buildings that are 2 kilometers (1.24 miles) from each other, with no obstructions in between. Your first required objective is to create a point-to-point link between the two buildings within the local regulatory body's 800 mW EIRP maximum. Your second required objective is to provide an industry-standard security solution capable of supporting mutual authentication. As an optional objective, you must minimize the amount of interference from, and to, nearby WLAN networks. You install an OFDM wireless bridge at each building, configuring one in root mode and the other in non-root mode. You set each radio for 100 mW (20 dBm) and attach 9 dBi omni-directional antennas to both. You configure the network for WPA2-Enterprise with PEAPv0/EAP-MSCHAPv2 authentication. Which statement is true about the solution you chose to deploy?

Your solution meets both required objectives, but does not meet the optional objective.

Q. Which unit of measurement is an absolute unit that is used to quantify power levels on a linear scale?

dBm