PW0-270 formatted€¦ · Exam A QUESTION 1 What HT PPDU format is shown in the exhibit? A....

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CWNA PW0-270

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Version: 5.0CWNA PW0-270 Exam

Exam A

QUESTION 1What HT PPDU format is shown in the exhibit?

A. HT-mixed formatB. HT-greenfield formatC. Non-HT formatD. Non-HT duplicate formatE. Dual Training Field formatF. ERP-OFDM format

Correct Answer: ASection: (none)Explanation

Explanation/Reference:Explanation:

QUESTION 2What is the purpose of a PHY preamble?

A. It provides the receiver(s) with an opportunity for RF channel synchronization prior to the start of thePLCP header.

B. It communicates important information about the PSDU's length, rate, and upper layer protocol- relatedparameters.

C. It provides a cyclic redundancy check (CRC) for the receiving station to validate that the PLCP headerwas received correctly.

D. It indicates to the PHY the modulation that shall be used for transmission (and reception) of the PSDU.



QUESTION 3When a 5 GHz HT station in a 40 MHz BSS desires to protect a 40 MHz transmission from an OFDMstation using an RTS/CTS or CTS-to-Self exchange, what frame format is used for the RTS and/or CTSframes?

A. HT-mixed formatB. HT-greenfield formatC. Dual-CTSD. Non-HT Duplicate

E. Phased Coexistence PPDU

Correct Answer: DSection: (none)Explanation


QUESTION 4What IEEE 802.11 technology is illustrated by the exhibit?

A. FragmentationB. TCP Fragment BurstingC. A-MSDUD. A-MPDUE. U-APSDF. Jumbo frames

Correct Answer: CSection: (none)Explanation


QUESTION 5Which statements are true regarding Beacons from an AP in an HT infrastructure BSS that is configuredwith multiple WLAN profiles? (Choose 3)


A. Beacons can be disabled for security purposes.B. The BSSID and Source Address are always the same.C. The Destination Address is always FF:FF:FF:FF:FF:FF.D. The Receiver address and the BSSID are always the same.E. When the SSID is "hidden," the ESS subfield of the Capability Information field distinguishes one BSS

from another.F. All Beacons generated by APs contain a TIM information element.G. The Beacon interval must be the same for all WLANs (SSIDs) supported by a single AP

Correct Answer: BCFSection: (none)Explanation


QUESTION 6Using the exhibit as a reference, answer the following.

STA1 sent a data frame to Mesh AP2 destined for a local file server on the same subnet with MAC address00:11:22:33:44:55. Mesh AP2's mesh forwarding algorithm determined that the frame should be forwardedthrough Mesh AP1.

In the frame sent from Mesh AP2 to Mesh AP1, what is true of the contents of the MAC header? (Choose3)

A. SA = Mesh AP2's MAC AddressB. RA = Mesh AP1's MAC AddressC. TA = STA1's MAC AddressD. DA = 00:11:22:33:44:55E. To DS = 0F. From DS = 1

Correct Answer: BDFSection: (none)Explanation


QUESTION 7According to 802.11-2007, in what frame type(s) might you find the PMK Count and PMKID List fields?

A. All frames that include the RSN IEB. Only (Re)Association Request framesC. Beacon and Probe Response framesD. EAPoL 4-Way Handshake framesE. Authentication and Association Request and Response frames

Correct Answer: BSection: (none)Explanation


QUESTION 8Which statement is true regarding the Association Identifier (AID) used in IEEE 802.11 WLANs?

A. The AID has a maximum value of 2048, and is used to uniquely identify a wireless client stationassociated with an access point.

B. The AID has a maximum value of 2007, and resides in the duration/ID field of a PS-Poll frame.C. The client station is assigned an AID value in the 802.11 authentication response frame.D. The AID field is present only in Beacons frames.E. The AID is used by the access point in EDCA mode to reduce duplicate transmissions when sending

multicasts.



QUESTION 9In which 802.11 frames is the SSID present, provided the SSID is not removed through proprietary softwareconfiguration by an administrator? (Choose 3)

A. Association RequestB. Reassociation RequestC. Probe ResponseD. DisassociationE. AuthenticationF. Association Response

Correct Answer: ABCSection: (none)Explanation


QUESTION 10In the frame decode shown, there are two sets of supported data rates. 1, 2, 5.5, and 11 Mbps are allshown as "basic" data rates, and 6, 9, 12, 18, 24, 36, 48, and 54 Mbps are shown simply as supported datarates.

What is true of "basic" data rates in this context?

A. The AP requires all client stations to support Basic rates in order to associate to its BSS.B. The highest data rate set to Basic is automatically used to send broadcast traffic such as Beacon

frames.C. Basic rates are optional data rates for the BSS, often used for assuring connectivity for legacy stations.D. Basic rates are only used for multicast traffic, and do not affect unicast traffic.E. Basic rates are defined in an AP's service set to specify mandatory data rates for all retry frames.



QUESTION 11

Given the frame capture and the decode shown,

after which Beacons in the list shown (as indicated by the frame number in the leftmost column) wouldmulticast traffic have been sent in this infrastructure BSS if multicast traffic had been queued fortransmission at the access point? (Choose 2)

A. Framenumber 49B. frame number 50C. frame number 51D. frame number 53E. frame number 54F. frame number 55G. frame number 57

Correct Answer: CFSection: (none)Explanation


QUESTION 12The Retry subfield is found in which IEEE 802.11 frame field?

A. Sequence Control fieldB. Protocol Order fieldC. Data Control fieldD. Frame Control fieldE. MAC Service Data Unit fieldF. QoS Control field



QUESTION 13Which information elements (IE) are contained in an IEEE 802.11 Probe Request frame? (Choose2)

A. RSN IEB. SSIDC. Status codeD. Association IDE. Supported rates

Correct Answer: BESection: (none)Explanation


QUESTION 14According to the IEEE 802.11 standard, what is one structural difference between a MAC Protocol DataUnit (MPDU) and a MAC Management Protocol Data Unit (MMPDU)?

A. The MPDU frame's FCS field is 4 bytes, while the MMPDU frame's FCS field is 8 bytes.B. The MMPDU frame body is limited to 300 bytes, whereas the MPDU frame body can carry up to 2304

bytes.C. The MPDU header always places the BSSID in the first address field, but in the MMPDU the BSSID can

be found in any of the address fields.D. An MMPDU header may only contain three address fields, but an MPDU may have four address fields.E. Both the MPDU and MMPDU have a QoS Control (QC) field, but all bits of the MMPDU's QC field are

always 0.



QUESTION 15

Which parameters accurately describe the Beacon Interval field in the Beacon frame? (Choose 2)

A. Value can range from 0 to 2007B. 4-octet lengthC. Indicates the exact time interval between Beacon transmissionsD. Indicates the desired time interval between TBTTsE. Measured in time units of 1024 µs

Correct Answer: DESection: (none)Explanation


QUESTION 16The IEEE 802.11 Dynamic Frequency Selection (DFS) service is capable of performing what functions?(Choose 2)

A. Establishing an interference baseline on all 2.4 GHz channelsB. Using modulation switching techniques to avoid interfering with radar systemsC. Testing channels for radar before using a channel and while operating in a channelD. Suspending operations on a channel with high IEEE 802.11 co-channel interferenceE. Requesting and reporting of measurements in the current and other channels

Correct Answer: CESection: (none)Explanation


QUESTION 17Which statements regarding an IEEE 802.11 Channel Switch Announcement frame are true? (Choose 2)

A. Channel Switch Announcement frames use the Action frame body format.B. Channel Switch Announcement frames are the only place where the Channel Switch Announcement

element is found.C. Channel Switch Announcement frames are transmitted and retransmitted on a channel until all

associated STAs successfully move to the new channel.D. Channel Switch Announcement elements may be carried in Beacon management frames.E. In an infrastructure BSS, Channel Switch Announcement frames may be transmitted by either the AP or

an associated STA.

Correct Answer: ADSection: (none)Explanation


QUESTION 18An HT STA does not receive an ACK for a first-attempt data frame that it transmitted. Assuming this STA isnot using BlockAcks in this case, what happens to the HT STA's EDCA contention window?

A. The slot time within the contention window decreases by 50%.B. It varies because the backoff algorithm is random.C. The contention window approximately doubles in size.D. The contention window is not affected by failed Data frame delivery.

E. The contention window is immediately closed, and the frame is retransmitted.



QUESTION 19What two IEEE 802.11 entities may be used to separate successful transmissions within an EDCA TXOP?(Choose 2)

A. SIFSB. AIFSC. ACKD. CAPE. PIFSF. EIFSG. RIFS

Correct Answer: AGSection: (none)Explanation


QUESTION 20How long, in microseconds, is the required Slot Time that is announced by an AP in an HT BSS when HR/DSSS, ERP-OFDM, and HT-OFDM client stations are associated to the AP?

A. 2 µsB. 4 µsC. 9 µsD. 10 µsE. 20 µs

Correct Answer: ESection: (none)Explanation


QUESTION 21Which statements accurately describe IEEE 802.11 EDCA collision handling in a WMM-compliantinfrastructure WLAN? (Choose 2)

A. When frames collide within a QoS STA, data frames from lower priority ACs behave (as it relates tocontention) as if there were an external collision on the wireless medium.

B. Collisions between contending EDCAFs within a QoS STA are resolved within the QoS STAC. When a frame transmission on the wireless medium fails, the transmitter may not transmit another

frame from any AC or to any destination until the frame experiencing a failure is successfully transmittedor the max retry count for that frame is reached.

D. The WMM specification requires use of RTS/CTS as part of the EDCAF within each QoS STA to avoidinternal collisions between ACs.

E. After frames collide within a QoS STA and the lower priority AC subsequently gains a TXOP, the retrybit in the MAC header must be set to 1 to indicate a retry.

Correct Answer: ABSection: (none)Explanation


QUESTION 22What must occur before an HT STA operating in an EDCA BSS can transmit a data frame over the wirelessmedium? (Choose 3)

A. Its NAV must be equal to one.B. The STA must receive a BlockAck, resetting the NAV to zero.C. The appropriate interframe space must expire.D. The backoff timer for the AC must equal zero.E. Its CCA must report that the medium is idle.F. The AP must issue the STA a TXOP.

Correct Answer: CDESection: (none)Explanation


QUESTION 23In the analyzer trace shown, the TBTT is nominally 102.5 milliseconds.

Why does the Beacon transmission interval vary?

A. The access point must arbitrate to gain access to the RF medium in order to transmit a Beacon.B. The DCF Interframe space (DIFS) is nominally 50 µs, but typically varies by as much as 10 µs, which

causes delays in Beacons.C. This trace shows an HT network where HR/DSSS nodes are active on the network. The access point is

changing slot times from short to long as needed.D. Beacon frames vary in size, and therefore some take slightly longer to send than others.



QUESTION 24Which statements are true regarding wireless network discovery and scanning processes for an HTnetwork? (Choose 2)

A. Client stations may continually send Probe Request frames on all HT channels in the 2.4 GHz ISM bandin a consecutive manner, regardless of their association state.

B. Access points send Beacon frames on all HT channels in the 2.4 GHz ISM band in a consecutivemanner including the channel for which the access point is configured.

C. Client stations send Probe Request frames on all HT channels in the 2.4 GHz ISM band in aconsecutive manner until they associate with an access point. After associating to an access point, theyno longer transmit Probe Request frames.

D. Access points send Beacon frames only on the HT channel in the 2.4 GHz ISM band for which theaccess point is configured, and only after scanning that channel to discover existing BSSs.

E. Client stations send Probe Request frames on all HT channels in the 2.4 GHz ISM band in aconsecutive manner until they receive at least 3 Probe Response frames.

Correct Answer: ADSection: (none)Explanation


QUESTION 25Which statements are true regarding frame acknowledgement in an IEEE 802.11 WLAN? (Choose3)

A. Following non-QoS Data frames with the More Fragments bit set to 1, the Duration/ID field of the ACKframe is set to a value equal to two SIFS plus the next Data fragment and its ACK.

B. A client station's Reassociation Request frames are only acknowledged with a Reassociation Responsefrom the access point and not with an ACK frame.

C. Probe request acknowledgement (sending of a Probe Response frame) is configurable in the accesspoint and is always linked to SSID broadcast configuration in Beacons.

D. In an EDCA BSS, encrypted Data frames are only acknowledged by client stations, never by accesspoints.

E. Data frame fragments are acknowledged individually (with an ACK frame).F. The RA field of ACK frames is always obtained from the Address 2 field in the corresponding frame

being acknowledged.

Correct Answer: AEFSection: (none)Explanation


QUESTION 26When an originator QoS STA initiates a BlockAck agreement with a recipient QoS STA, what is the firstframe sent by the originator?

A. BlockAckSetupReqB. BlockAckReqC. ADDBA RequestD. BlockAckPolicyReqE. ActionBAReq



QUESTION 27In an HT WLAN in which a delayed Block Ack policy is set up, what should result when an ACK frame is notreceived by the originator in response to a Basic BlockAckReq?

A. All frames within that block must be retransmitted by the originator.B. The last frame within that block must be retransmitted by the originator.C. The BlockAckReq must be retransmitted by the originator.D. Nothing. No ACK is expected in response to a Basic BlockAckReq.



QUESTION 28According to the 802.11n-2009 amendment, what security requirement is specified for HT BSSs?

A. In an RSN, HT stations may not communicate with one another using TKIP.B. TKIP cannot be supported in an HT BSS.C. All unicast traffic transmitted by an HT station and destined to an HT station must use AES- CCMP.D. HT BSSs are prevented from supporting WEP.E. HT BSSs must mandatorily support 802.11r FT.



QUESTION 29The 802.11r-2008 amendment to the 802.11 specification introduces what new Information Elements (IEs)to facilitate fast BSS transitions? (Choose 2)

A. RSN IE (Robust Security Network)B. FSR IE (Fast Secure Roaming)C. HT IE (High Throughput)D. MD IE (Mobility Domain)E. FT IE (Fast Transition)F. DS IE (Distribution System)

Correct Answer: DESection: (none)

Explanation


QUESTION 30To effect Preauthentication, a STA's supplicant sends an IEEE 802.1X/EAPoL Start message.How is the EAPoL Start message addressed?

A. DA = MAC of default gateway; RA = BSSID of the AP to which the STA is associatedB. DA = BSSID of targeted AP; RA = BSSID of the AP to which the STA is associatedC. DA = MAC of the default gateway; RA = Ethernet MAC of the targeted APD. DA = BSSID of the targeted AP; RA = Ethernet MAC of the targeted AP



QUESTION 31Which statement accurately describes IEEE 802.11 Power Save operation in a Basic Service Set that doesnot support the QoS facility?

A. Following a period of time in a low power state, client stations wake themselves and automatically pollthe access point for traffic using a PS-Poll frame.

B. When the access point's buffer is full, the access point wakes all client stations using a PS-Poll frameso that they can receive the data.

C. Upon receiving traffic for a dozing station, the access point wakes the client station using a PS- Pollframe so that the client station can receive the data.

D. After waking from a low power state, client stations listen for the next Beacon to determine if sending aPS-Poll frame to the access point is necessary.

E. After waking at a scheduled TBTT, client stations send Null Function frames to the access point with thePower Management bit set back to zero.



QUESTION 32Given: Your network consists of HT and ERP access points, and you are implementing VoWiFi with supportfor U-APSD.

When an ERP handset operating in WMM Power Save mode with a ReceiveDTIMs parameter of TRUEreceives a Beacon containing a DTIM indicating queued broadcast traffic, what task is the handset requiredto perform?

A. The handset must send a PS-Poll frame to the access point for every broadcast frame it receives withthe More Data bit set to one.

B. The handset must arbitrate for the medium and immediately issue an RTS directed to the access pointwith the NAV set to a value of 32,768.

C. The handset must broadcast a CTS-to-Self frame indicating the station's need to control the mediumlong enough to receive all of the broadcast frames.

D. The handset is to remain awake to receive the broadcast frame(s) following the Beacon that containsthe DTIM.



QUESTION 33WMM-PS trigger frames can be what type of IEEE 802.11 frames? (Choose 2)

A. QoS NullB. ReassociationC. QoS DataD. CTSE. QoS ActionF. PS-Poll

Correct Answer: ACSection: (none)Explanation


QUESTION 34IEEE 802.11-2007 specifies two ERP protection mechanisms: RTS/CTS and CTS-to-Self. Which statementis true regarding these two protection mechanisms? (Choose 2)

A. RTS and CTS frames use Short Interframe Spaces (SIFS), and CTS-to-Self frames use PCF InterframeSpaces (PIFS).

B. Use of RTS/CTS requires more overhead than CTS-to-Self due to a higher number of framestransmitted onto the wireless medium.

C. RTS and CTS frames are relayed through the access point, whereas the CTS-to-Self frames are not.D. A CTS-to-Self frame sent by a client station may reach fewer nodes than the RTS/CTS frame

exchange.E. By definition, all associated client stations in a BSS can hear RTS, CTS, and CTS-to-Self frames, so

RTS/CTS and CTS-to-Self mechanisms have equal effectiveness.F. Aside from the Subtype subfield of the Frame Control field, the generic MAC header format of RTS and

CTS frames are identical.

Correct Answer: BDSection: (none)Explanation


QUESTION 35As it pertains to HT L-SIG TXOP Protection, what statement is true?

A. Support for L-SIG TXOP Protection is indicated by HT stations in the L-SIG field of the PLCP header ofHT-mixed format frames.

B. Support for L-SIG TXOP Protection is indicated in the HT Capabilities Info field of (re)associationrequest frames sent by ERP, OFDM, and HT-OFDM stations.

C. An L-SIG TXOP protected frame exchange sequence always begins with an RTS/CTS or a CTS-to-Self.D. L-SIG TXOP Protection is specified for the purpose of protecting OFDM (802.11a/g) and HT- OFDM

(802.11n) transmissions from HR/DSSS stations.

Correct Answer: CSection: (none)

Explanation


QUESTION 36When a client station operating under EDCA sends an RTS frame and NAV protection is desired for onlythe first or sole frame in the TXOP, the duration field will contain an amount of time, measured inmicroseconds, equal to which of the following?

A. 1 RTS, 2 ACK, 1 DATA, 4 SIFSB. 1 CTS, 1 ACK, 1 DATA, 3 SIFSC. 1 RTS, 1 ACK, 1 DATA, 2 SIFS, 1 DIFSD. 1 RTS, 1 CTS, 2 ACK , 1 DATA, 4 SIFSE. 1 CTS, 2 ACK, 1 DATA, 2 SIFSF. The entire duration of the TXOP



QUESTION 37Many access points support IEEE 802.1Q VLAN tagging. When analyzing a WLAN system using IEEE802.1Q tags, where can the VLAN tag number be seen?

A. In the Sequence Control field of the MSDUB. In the PLCP header's Service fieldC. In the Frame Control field of the MPDU headerD. In the Ethernet header on the wired port of the access pointE. In the Beacon Management frame's Capabilities fixed field



QUESTION 38With what access category's parameters are WLAN multicast video frames transmitted when the EDCAF isin use by the transmitting station?

A. AC_VIB. AC_VOC. AC_BED. AC_BK



QUESTION 39What is indicated to a QoS AP when a QoS STA sets U-APSD Flag bits to 1 in (Re) Association frames?

A. Which access categories are both trigger-enabled and delivery-enabledB. Which user priorities require use of a TSPECC. Which access categories require admission controlD. Which user priorities are mapped to access categoriesE. Which access categories are scheduled



QUESTION 40Your wireless network troubleshooting kit includes an antenna with the following specifications:

Gain: 5 dBi

Azimuth Beamwidth: 55 degrees

Elevation Beamwidth: 50 degrees

Frequency Range: 2.4 - 2.5 GHz and 4.9 - 5.9 GHz

Polarization: Linear

Impedance: 50 Ohms

For what aspect of network troubleshooting would this antenna be most useful?

A. Capturing BSS-wide CRC error and retry statistics in most indoor WLAN environmentsB. Identifying problems with Fresnel zone clearance in long range (10+ miles / 16+ km) point-to- point linksC. Finding the physical location of an interfering transmitter to identify and remove the sourceD. Increasing resolution bandwidth (RBW) on a spectrum analyzer to improve signature identification

featuresE. Matching transmit and receive capabilities for most client stations to reproduce client reception issues



QUESTION 41Given: The exhibit shows a small network environment with dual-band APs.

What is true of the network shown in this spectrum analyzer trace?

A. There are at least three APs operating in this environment. They are operating on channels 149, 153,and 161.

B. There are two 40 MHz BSSs in this environment. One AP has some 40 MHz traffic while the other APhas no client traffic.

C. Only one AP in this network is configured to use the upper UNII band (UNII-3). All other APs are inlower 5 GHz channels.

D. Two 802.11a APs are near the spectrum analyzer and are heavily utilized on channels 149 and 153.



QUESTION 42Given: ABC Company recorded the 2.4 GHz band with a spectrum analyzer prior to installing their ERPWLAN. Image-A is how the band appeared prior to the WLAN installation. Image-B is how the band

appears now, and all channels on their WLAN have ceased to function.

What is the best explanation as to why their WLAN is no longer functioning properly?

A. A wideband RF power source is corrupting all IEEE 802.11 transmissions.B. A new microwave oven was installed in the cafeteria.C. A malfunctioning IEEE 802.11 OFDM radio card is transmitting continuously.D. A manual site survey tool is actively testing the throughput of their WLAN.E. A Terminal Doppler Weather Radar (TDWR) is causing a DFS response across the entire band.



QUESTION 43What types of wireless systems are illustrated?

A. An ERP IEEE 802.11 system using channel 6 and Bluetooth v1.2 discoveryB. A Bluetooth v2.0 file transfer and a 40 MHz HT AP on channels 11, 7 (primary, secondary)C. A 2.4 GHz cordless phone on channel 14 and a wireless RFID readerD. An 802.11 HR/DSSS system using channel 2 and a digital FHSS phone



QUESTION 44Given: The graphic is taken from a spectrum analyzer.

What types of RF transmitters are illustrated?

A. An IEEE 802.11 HR/DSSS security camera on channel 6 and an RFID tagB. A Bluetooth headset and a narrowband RF jamming deviceC. A 2.4 GHz cordless phone and an OpenAir FHSS systemD. A 20 MHz HT IEEE 802.11 system using channel 1 and a microwave oven



QUESTION 45Given: Before installing a Wi-Fi network, ABC Company performed a spectrum analysis looking forproblems. The 2.4 GHz RF spectrum looked like Image-A. After installing an ERP WLAN, ABC Companyperformed another spectrum analysis during business hours. The 2.4 GHz RF spectrum then looked like

Image-B close to an AP on channel 1.

Now the 2.4 GHz RF spectrum looks like Image-C and access points and clients can no longercommunicate on channel 1. What is happening on channel 1?

A. The access point's antenna connectors have been tampered with, causing "spike and shear" RFtransmissions that are not compatible with the OFDM PHY format. For that reason, client devicescannot receive the AP's transmissions without error.

B. A high-power, narrowband RF interference source on channel 1 is causing the CCA energydetects(ED)function on 802.11 devices to indicate a busy medium because the signal source is above the EDthreshold.

C. Stronger transmissions from licensed 2.4 GHz users, such as HAM operators, are compressing thetransmissions from the channel 1 access points into the lower portion of the band.

D. The shape of the signals in images B and C indicates that a licensed user in this frequency range hasenabled the "guard bands" in an effort to restrict local interference with other systems.

E. Detection of a DFS radar event has discontinued 802.11 operation on channel 1, but the access point'sChannel Switch Announcement frame cannot be sent due to the presence of radar.



QUESTION 46As it relates to a spectrum analyzer, complete the following sentence.

The ____________ plot always displays the percentage of time (shown on the Y axis) that the overall RFpower is a certain specified threshold (of amplitude) above the noise floor for a given frequency range(shown on the X axis).

A. Real-Time FFTB. Swept SpectrogramC. FFT Duty CycleD. Interferer CountE. SNR



QUESTION 47Using the exhibit as a reference,

which spectrum plots display, in real time, the value of RF amplitude as a function of radio frequency?

A. 1 and 2B. 1 and 3C. All of the plotsD. 1, 3, and 4E. 3 and 4



QUESTION 48As shown in the exhibit, a spectrum analyzer has measured both 802.11 and non-802.11 RF transmissionsin the 2.4 GHz band. The exhibit shows a continuous video transmitter near channel 5.

Based upon the exhibit,

what impact does the video transmitter have on WLAN operations throughout the band?

A. The video transmitter is preventing WLAN operation on channel 6, and has only a minor impact onchannels 1 and 11.

B. The video transmitter has made no impact on WLAN operation in the band.C. The video transmitter is preventing all WLAN transmissions in the band.D. The video transmitter is preventing all WLAN transmissions on channel 6, and its impact on channels 1

and 11 is severe.



QUESTION 49What MAC layer information will a dual-band 802.11n protocol analyzer capture if it is capturing data framesencrypted with WPA2-Enterprise? (Choose 2)

A. Source IP AddressB. Null Data framesC. TCP SYN datagramD. Short Interframe SpacesE. Sequence Control fieldsF. Legacy Signal field

Correct Answer: BESection: (none)Explanation


QUESTION 50ABC Company is having VoWiFi latency problems on their 802.11g WLAN. A wireless administrator hasnoticed in the phone's client utilities software that the MAC CRC Error count is higher on stations withproblems than on those client stations without problems.

A high MAC CRC Error count is attributable to which of the following? (Choose 3)

A. High collision rates due to dense population of voice stations and no admission controlB. Two access points with overlapping coverage on a single channelC. High multipath conditions due to an RF environment with highly reflective materialsD. 2.4 GHz ISM band interference from sources such as wireless video cameras and analog phonesE. Co-located DCF and EDCA access points that are using non-overlapping 2.4 GHz channelsF. Dynamic Rate Switching algorithms that decrease data rates for latency-sensitive applications

Correct Answer: ACDSection: (none)Explanation


QUESTION 51While at a government-operated facility, you are attempting to troubleshoot a WLAN performance problemusing a wireless protocol analyzer. When you start capturing frames, you see a proprietary layer 2 protocolrunning over the ERP network as shown in this screenshot. The facility's WLAN administrator confirms thatthis protocol is proprietary and used for both data encryption and compression.

How will this information affect the steps you take to troubleshoot performance problems on this WLAN?

A. The proprietary encryption protocol will have no effect on your troubleshooting steps because thewireless protocol analyzer can still decode the PLCP and MAC headers of Data frames. This situation isessentially no different than troubleshooting a WLAN that uses WPA2-Personal.

B. Troubleshooting will be somewhat limited because only part of the information needed for performancemeasurements by the analyzer is encrypted. Each Data frame's MAC header will be encrypted, but thePLCP header can still be decoded successfully.

C. As long as you load the proprietary software codec onto your analyzer computer, you will be able to seeall of the Data frame information fully decoded. Loading the proprietary software codec will allow you totroubleshoot the WLAN as though no encryption were in use.

D. In order to troubleshoot performance problems on a network using proprietary encryption protocols likethis one, you must use a wireless protocol analyzer that has integrated support for the protocol in use.



QUESTION 52Given: Shown are frames captured from an IEEE 802.1X/LEAP authentication. This WLAN is a RobustSecurity Network (RSN) using the CCMP cipher suite.

Using the information given in the screenshot, calculate how long it takes for only the frames that are part ofthe 4-Way handshake to complete.

A. 3.018 msB. 5.820 msC. 210.443 msD. 237.753 msE. 243.743 ms



QUESTION 53ABC Company's WLAN administrator is getting complaints from one user that his WLAN throughput issluggish compared to other users in his area. The administrator takes his diagnostics laptop, which has awireless protocol analyzer installed, to the area where the complaining user works. The administrator usesthe PING utility to test connectivity from the complaining user's wireless client station to another wirelessclient station across the closest access point, while capturing the wireless frames. The administrator seeswhat is displayed in this screenshot.

From this screenshot, which statements can you conclude to be TRUE that are related to the complaininguser's throughput problem? (Choose 2)

A. The complaining user's WLAN client utilities are configured with a small fragmentation threshold.B. The complaining user's station is retransmitting fragments many times likely due to nearby RF

interference.C. The access point and other stations are using ERP-OFDM modulation, and the complaining user's

wireless client station is using HR/DSSS modulation.D. The complaining user's wireless client station should be using RTS/CTS as a protection mechanism,

but it is not.E. The access point is not signaling for protection (Protection = no) in the Beacons, but it should be.

Correct Answer: ACSection: (none)Explanation


QUESTION 54Given: There are many differences between analyzing wireless and wired networks. In a wireless network,there is no guarantee that one station can hear another station's transmissions.

If no corrective actions are taken nor corrective mechanisms implemented when a "hidden node" problemexists, which measurable statistics parameter will likely increase in a wireless protocol analyzer?

A. Duration valueB. Retransmission CountC. Contention Window

D. Authentication FailureE. BlockAck ResetF. ACK Timeout



QUESTION 55When 802.11 standard compliant AES-CCMP security is being used with IPSec/ESP for layered security,what will a WLAN protocol analyzer see as the security mechanism in use when a user browses to anHTTPS secured web page?

A. AES-CCMPB. IPSec/ESPC. SSLv3D. AES-CCMP and IPSec/ESPE. AES-CCMP, IPSec/ESP, AND SSLv3



QUESTION 56Given the IEEE 802.11 Beacon frame decode shown,

determine which statement is definitively true.

A. The access point is operating on channel 3.B. The access point has both 1 Mbps and 2 Mbps configured as basic rates.C. This Beacon frame came from an ERP or HT access point.D. The SSID value in this Beacon is null.E. ERP mobile stations must use the RTS/CTS protocol before Data transmissions.



QUESTION 57Given the screenshot shown,

Choose the statement that accurately describes what is being seen by this protocol analyzer.

A. Three access points are on the same channel in the same physical area.B. A Single Channel Architecture (SCA) WLAN solution has three WLAN profiles configuredC. One access point is using the 802.11 round robin Beacon feature.D. Three wireless stations are participating in an Ad Hoc WLAN.



QUESTION 58Shown is a screenshot of a wireless protocol analyzer displaying the decode information for a single 802.11encrypted data + CF-Poll frame. The infrastructure BSS on which this information was captured is usingWEP and this particular frame was sent from a client station (STA) to an access point (AP).

As a protocol analyst, how would you explain the existence of this frame on the wireless medium given theinformation in the decode?

A. The IEEE 802.11 network is using both version 1 and version 2 protocols simultaneously. Thisunexpected frame is from the version 2 protocol set.

B. The frame was sent by a client station that does not comply with IEEE HR/DSSS standard to an accesspoint that is Wi-Fi certified.

C. The access point is operating as a repeater, and clients must poll repeater access points in order totransmit data frames through them.

D. The frame was misinterpreted because of insufficient information received by the analyzer due to framecorruption.



QUESTION 59As a WLAN consultant, you have been asked to troubleshoot a problem with a single wireless client station(Station-Z). Your customer informs you that other wireless client stations are not having problems withwireless connectivity, and that Station-Z is configured in the same manner as all other wireless clientstations on the network. Station-Z is showing an unusually high retransmission count in its client utilitystatistics. Using a wireless protocol analyzer, where and how should you begin troubleshooting thisproblem? (Choose 2)

A. Position the analyzer halfway between Station-Z and the access point. Measure the distance between

Station-Z and the access point.B. Position the analyzer near Station-Z. Analyze Station-Z's transmissions and acknowledgements. Look

for RF and obstacle-induced interference.C. Position the analyzer near the access point. See if Station-Z's frames are reaching the access point and

if so, analyze their signal strength.D. Position the analyzer near Station-Z. Analyze the frames Station-Z is receiving, looking for delayed ACK

frames.E. Position the analyzer halfway between Station-Z and the access point. Analyze the data rate at which

frames are sent and how long they take to be received.

Correct Answer: BCSection: (none)Explanation


QUESTION 60Why is a high CRC error rate in L2 protocol analysis software NOT always a valid indicator of networkperformance? (Choose 3)

A. If protocol analysis software is not properly configured with frame decryption parameters, it can'taccurately calculate a CRC, which includes the encrypted frame body contents.

B. If the protocol analysis radio hardware is not located in the same area as intended client devices or APs,its data sampling may not be representative of actual traffic on the network.

C. Radio and antenna hardware used for protocol analysis may not match the receive sensitivity, diversity,MIMO, or antenna gain capabilities of the network WLAN hardware.

D. Layer 2 protocol analysis can only collect and interpret data that is received properly at the MAC layer,and cannot quantify some PHY-layer problems.

Correct Answer: BCDSection: (none)Explanation

Explanation/Reference:


PW0-270 formatted€¦ · Exam A QUESTION 1 What HT PPDU format is shown in the exhibit? A....

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