Test
wireless test 2
Este test tiene tipos de pregunta que se abren en el reproductor de siempre.
Preguntas del test (84)
1Which of the following are valid ISM bands? (Choose all that apply.)
- AA. 902-928 MHz
- BB. 2.4-2.5 GHz
- CC. 5.725-5.825 GHz
- DD. 5.725-5.875 GHz
2Which of the following are valid UNII bands? (Choose all that apply.)
- AA. 5.150-5.250 GHz
- BB. 5.47-5.725 GHz
- CC. 5.725-5.825 GHz
- DD. 5.725-5.850 GHz
3Which technologies are used in the 2.4 GHz ISM band? (Choose all that apply)
- AA. FHSS
- BB. ERP
- CC. DSSS
- DD. HR-DSSS
4802.11n (HT clause 20 radios) can transmit in which frequency bands? (Choose all that apply)
- AA. 2.4-2.4835 GHz
- BB. 5.47-5.725 GHz
- CC. 902-928 GHz
- DD. 5.15-5.25 GHz
5In the UNII-1 band, what is the center frequency of channel 40?
- AA. 5.2 GHz
- BB. 5.4 GHz
- CC. 5.8 GHz
- DD. 5.140 GHz
6What is the channel and band of a Wi-Fi transmission whose center frequency is 5.300 GHz?
- AA. UNII-1 channel 30
- BB. UNII-1 channel 60
- CC. UNII-2 channel 30
- DD. UNII-2 channel 60
7The 802.11-2007 standard requires how much separation between center frequencies for HR-DSSS (clause 18) channels to be considered nonoverlapping?
- AA. 22 MHz
- BB. 25 MHz
- CC. 30 MHz
- DD. 35 MHz
- EE. 40 MHz
8What best describes hop time?
- AA. The period of time that the transmitter waits before hopping to the next frequency
- BB. The period of time that the standard requires when hopping between frequencies
- CC. The period of time that the transmitter takes to hop to the next frequency
- DD. The period of time the transmitter takes to hop through all of the FHSS frequencies
9As defined by the IEEE-2007 standard, how much separation is needed between center frequencies of channels in the UNII-2 Extended band?
- AA. 10 MHz
- BB. 20 MHz
- CC. 22 MHz
- DD. 25 MHz
- EE. 30 MHz
10When deploying an 802.11g (ERP-OFDM) wireless network with only two access points, which of these channel groupings would be considered nonoverlapping? (Choose all that apply)
- AA. Channels 1 and 3
- BB. Channels 7 and 10
- CC. Channels 3 and 8
- DD. Channels 5 and 11
- EE. Channels 6 and 10
11Which spread spectrum technology specifies data rates of 22 Mbps and 33 Mbps?
- AA. DSSS
- BB. ERP-PBCC
- CC. OFDM
- DD. PPtP
12If data is corrupted by previous data from a reflected signal, this is known as what?
- AA. Delay spread
- BB. ISI
- CC. Forward error creation
- DD. Bit crossover
13Assuming all channels are supported by a 5 GHz access point, how many possible channels can be configured on the access point?
- AA. 4
- BB. 11
- CC. 12
- DD. 24
14Which of these technologies is the most resilient against the negative effects of multipath?
- AA. FHSS
- BB. DSSS
- CC. HR-DSSS
- DD. OFDM
15HR-DSSS (clause 18) calls for data rates of 5.5 Mbps, and 11 Mbps, What is the average amount of aggregate throughput percentage at any data rate?
- AA. 80 percent
- BB. 75 percent
- CC. 50 percent
- DD. 100 percent
16As defined in the IEEE 802.11-2007 Standard, choose the answer that shows the number of channels in each of the UNII bands, listed in the following order: UNII-1, UNII-2, UNII-2e, UNII-3.
- AA. 4,4,14,4
- BB. 4,4,11,4
- CC. 8,4,11,4
- DD. 4,4,4,11
17With the center frequency of channel 1 at 2.412 GHz, what is the center frequency of channel 2?
- AA. 2.444 GHz
- BB. 2.417 GHz
- CC. 2.424 GHz
- DD. 2.422 GHz
18What are the modulation types used by OFDM technology ? (Choose all that apply)
- AA. QAM
- BB. Phase
- CC. Frequency
- DD. Power
19The Barker code converts a bit of data into a series of bits that are referred to as what?
- AA. Chipset
- BB. Chips
- CC. Convolutional code
- DD. Complementary code
20OFDM uses how many 312.5 KHz data subcarriers when transmitting?
- AA. 54
- BB. 52
- CC. 48
- DD. 36
21An 802.11 wireless network name is known as which type of address? (Choose all that apply.)
- ABSSID
- BMAC address
- CIP address
- DSSID
- EExtended service set identifier
22Which two 802.11 topologies require the use of an access point?
- AA. WPAN
- BB. IBSS
- CC. Basic service set
- DD. Ad hoc
- EE. ESS
23The 802.11 standard defines which medium to be used in a distribution system (DS)?
- AA. 802.3 Ethernet
- BB. 802.15
- CC. 802.5 token ring
- DD. Star-bus topology
- EE. None of the above
244. Which option is a wireless computer topology used for communication of computer devices within close proximity of a person?
- AA. WLAN
- BB. Bluetooth
- CC. ZigBee
- DD. WPAN
- EE. WMAN
25Which 802.11 service set may allow for client roaming?
- AA. ESS
- BB. Basic service set
- CC. Colocated APs
- DD. IBSS
- EE. Spread spectrum service set
26What is the default configuration mode that allows an AP radio to operate in a basic service set?
- AA. Scanner
- BB. Repeater
- CC. Root
- DD. Access
- EE. Nonroot
27Which terms describe an 802.11 topology involving STAs but no access points? (Choose all that apply.)
- AA. BSS
- BB. Ad hoc
- CC. DSSS
- DD. Infrastructure
- EE. IBSS
- FF. Peer-to-peer
28What factors might affect the size of a BSA coverage area of an access point? (Choose all that apply.)
- AA. Antenna gain
- BB. CSMA/CA
- CC. Transmission power
- DD. Indoor/outdoor surroundings
- EE. Distribution system
29STAs operating in infrastructure mode may communicate in which of the following scenarios? (Choose all that apply.)
- AA. 802.11 frame exchanges with other STAs via an AP
- BB. 802.11 frame exchanges with an AP in scanner mode
- CC. 802.11 frame peer-to-peer exchanges directly with other STAs
- DD. Frame exchanges with network devices on the DSM
- EE. All of the above
30What are the only three original topologies defined by the 802.11-2007 standard? (Choose all that apply.)
- AA. Bridge mode
- BB. Extended service set
- CC. BSS
- DD. IBSS
- EE. FHSS
31Which wireless topology provides citywide wireless coverage?
- AA. WMAN
- BB. WLAN
- CC. WPAN
- DD. WAN
- EE. WWAN
32At which layer of the OSI model will a BSSID address be used?
- AA. Physical
- BB. Network
- CC. Session
- DD. Data-Link
- EE. Application
33The basic service set identifier address can be found in which topologies? (Choose all that apply.)
- AA. FHSS
- BB. IBSS
- CC. ESS
- DD. DSSS
- EE. BSS
34Which 802.11 service set defines mechanisms for mesh networking?
- AA. BSS
- BB. DSSS
- CC. ESS
- DD. MBSS
- EE. IBSS
35What method of dialog communications is used within an 802.11 WLAN?
- AA. Simplex communications
- BB. Half-duplex communications
- CC. Full-duplex communications
- DD. Dual-duplex communications
36What are some nonstandard modes in which an AP radio may be configured? (Choose all that apply.)
- AA. Scanner
- BB. Root
- CC. Bridge
- DD. Nonroot
- EE. Repeater
37A network consisting of clients and one or more access points with the same SSID connected by an 802.3 Ethernet backbone is one example of which 802.11 topology? (Choose all that apply.)
- AA. ESS
- BB. Basic service set
- CC. Extended service set
- DD. IBSS
- EE. Ethernet service set
38What term best describes two access points communicating with each other wirelessly while also allowing clients to communicate through the access point?
- AA. WDS
- BB. DS
- CC. DSS
- DD. DSSS
- EE. DSM
39What components make up a distribution system? (Choose all that apply.)
- AA. HR-DSSS
- BB. Distribution system services
- CC. DSM
- DD. DSSS
- EE. Intrusion detection system
40What type of wireless topology is defined by the 802.11 standard?
- AA. WAN
- BB. WLAN
- CC. WWAN
- DD. WMAN
- EE. WPAN
41DCF is also known as what? (Choose all that apply)
- AA. Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
- BB. Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)
- CC. Data Control Function
- DD. Distributed Coordination Function
42802.11 collision detection is handled using which technology?
- AA. Network allocation vector (NAV).
- BB. Clear channel assessment (CCA).
- CC. Duration/ID value.
- DD. Receiving an ACK from the destination station
- EE. Positive collision detection cannot be determined
43ACK and CTS-to-self frames follow which interframe space?
- AA. EIFS
- BB. DIFS
- CC. PIFS
- DD. SIFS
- EE. LIFS
44The carrier sense portion of CSMA/CA is performed by using which of the following methods? (Choose all that apply)
- AA. Virtual carrier sense
- BB. Physical carrier sense
- CC. Channel sense window
- DD. Clear channel assessment
45After the station has performed the carrier sense and determined that no other devices are transmitting for a period of a DIFS interval, what is the next step for the station?
- AA. Wait the necessary number of slot times before transmitting, if a random back-off value has already been selected.
- BB. Begin transmitting.
- CC. Select a random back-off value.
- DD. Begin the random back-off timer.
46If PCF is implemented, it can function in which of the following network environments? (Choose all that apply)
- AA. Ad hoc mode
- BB. BSS
- CC. IBSS
- DD. Infrastructure mode
- EE. BSA
47Which of the following terms are affiliated with the virtual carrier-sense mechanism? (Choose all that apply)
- AA. Contention window
- BB. Network allocation vector
- CC. Random back-off time
- DD. Duration/ID field
48The goal of allocating equal time as opposed to equal opportunity is known as what?
- AA. Access fairness
- BB. Opportunistic media access
- CC. CSMA/CA
- DD. Airtime fairness
49CSMA/CA and DCF define which mechanisms to ensure that only one 802.11 radio can transmit on the half-duplex RF medium? (Choose all that apply)
- AA. Random back-off timer
- BB. NAV
- CC. CCMP
- DD. CCA
- EE. Interframe spacing
50The Wi-Fi Alliance certification called Wi-Fi Multimedia (WMM) is based on which media access method defined by the 802.11-2007 standard?
- AA. DCF
- BB. PCF
- CC. EDCA
- DD. HCCA
- EE. HSRP
51Hybrid Coordination Function (HCF) defines what allotted period of time in which a station can transmit multiple frames?
- AA. Block acknowledgment
- BB. Polling
- CC. Virtual carrier sense
- DD. Physical carrier sense
- EE. TXOP
52Currently, WMM is based on EDCA and provides for traffic prioritization via which of the following access categories? (Choose all that apply)
- AA. WMM Voice priority
- BB. WMM Video priority
- CC. WMM Audio priority
- DD. WMM Best Effort priority
- EE. WMM Background priority
53The 802.11e amendment (now part of the 802.11-2007 standard) defines which of the following medium access methods to support QoS requirements? (Choose all that apply)
- AA. Distributed Coordination Function (DCF)
- BB. Enhanced Distributed Channel Access (EDCA)
- CC. Hybrid Coordination Function (HCF)
- DD. Point Coordination Function (PCF)
- EE. Hybrid Coordination Function Controlled Access (HCCA)
54What information that comes from the wired side network is used to assign traffic into access categories on a WLAN controller?
- AA. Duration/ID
- BB. 802.1D priority tags
- CC. Destination MAC address
- DD. Source MAC address
55What are the two reasons that 802.11 radios use physical carrier sense? (Choose two)
- AA. To synchronize incoming transmissions
- BB. To synchronize outgoing transmissions
- CC. To reset the NAV
- DD. To start the random back-off timer
- EE. To assess the RF medium
56What CSMA/CA mechanism is used for medium contention? (Choose all that apply)
- AA. NAV
- BB. CCA
- CC. Random back-off timer
- DD. Contention window
57Which field in the MAC header of an 802.11 frame reset the NAV timer for all listening 802.11 stations?
- AA. NAV
- BB. Frame control
- CC. Duration/ID
- DD. Sequence number
- EE. Strictly ordered bit
58The EDCA medium access method provides for the prioritization of traffic via priority tags that are identical to the 802.1D priority tags. What are the EDCA priority tags known as?
- AA. TXOP
- BB. UP levels
- CC. Priority levels
- DD. Priority bits
- EE. PT
59ACKs are required for which of the following frames?
- AA. Unicast
- BB. Broadcast
- CC. Multicast
- DD. Anycast
60What QoS mechanism can be used to reduce medium contention overhead during a frame burst of low-latency traffic?
- AA. Delayed Block ACK
- BB. Contention period
- CC. Contention window
- DD. Contention-free period
- EE. Immediate Block ACK
61Which of the following contains only LLC data and the IP packet, but does not include any 802.11 data?
- AA. MPDU
- BB. PPDU
- CC. PSDU
- DD. MSDU
- EE. MMPDU
62If WMM-PS is not supported, after a station sees its AID set to 1 in the TIM, what typically is the next frame that the station transmits?
- AA. Data
- BB. PS-Poll
- CC. ATIM
- DD. ACK
63Which of the following are true about beacon management frames? (Choose all that apply.)
- AA. Beacons can be disabled to hide the network from intruders.
- BB. Time-stamp information is used by the clients to synchronize their clocks.
- CC. In a BSS, clients share the responsibility of transmitting the beacons.
- DD. Beacons can contain vendor-proprietary information.
64Which of the following information is included in a probe response frame? (Choose all that apply.)
- AA. Time stamp
- BB. Supported data rates
- CC. Service set capabilities
- DD. SSID
- EE. Traffic indication map
65The presence of what type of transmissions can trigger the protection mechanism within an ERP basic service set? (Choose all that apply.)
- AA. Association of an HR-DSSS client
- BB. Association of an ERP-OFDM client
- CC. HR-DSSS beacon frame
- DD. ERP beacon frame with the NonERP_Present bit set to 1
- EE. Association of an FHSS client
66Which of the following are protection mechanisms? (Choose all that apply.)
- AA. NAV back-off
- BB. RTS/CTS
- CC. RTS-to-Self
- DD. CTS-to-Self
- EE. WEP encryption
67What is the difference between association frames and reassociation frames? (Choose all that apply.)
- AA. Association frames are management frames, whereas reassociation frames are control frames.
- BB. Fast BSS transition only uses reassociation frames.
- CC. Association frames are used exclusively for roaming.
- DD. Reassociation frames contain the BSSID of the original AP.
- EE. Only association frames are used to join a BSS.
68When a station sends an RTS, the Duration/ID field notifies the other stations that they must set their NAV timers to which of the following values?
- AA. 213 microseconds
- BB. The time necessary to transmit the DATA and ACK frames
- CC. The time necessary to transmit the CTS frame
- DD. The time necessary to transmit the CTS, DATA, and ACK frames
69How does a client station indicate that it is using Power Save mode?
- AA. It transmits a frame to the AP with the Sleep field set to 1.
- BB. It transmits a frame to the AP with the Power Management field set to 1.
- CC. Using DTIM, the AP determines when the client station uses Power Save mode.
- DD. It doesn't need to, because Power Save mode is the default.
70What would cause an 802.11 station to retransmit a unicast frame? (Choose all that apply.)
- AA. The transmitted unicast frame was corrupted.
- BB. The ACK frame from the receiver was corrupted.
- CC. The receiver's buffer was full.
- DD. The transmitting station will never attempt to retransmit the data frame.
- EE. The transmitting station will send a retransmit notification.
71If a station is in Power Save mode, how does it know that the AP has buffered unicast frames waiting for it?
- AA. By examining the PS-Poll frame
- BB. By examining the TIM field
- CC. When it receives an ATIM
- DD. When the Power Management bit is set to 1
- EE. DTIM interval
72When is an ERP (802.11g) AP required by the IEEE 802.11-2007 standard to respond to probe request frames from nearby HR-DSSS (802.11b) stations? (Choose all that apply.)
- AA. When the probe request frames contain a null SSID value
- BB. When the AP supports only ERP-OFDM data rates
- CC. When the AP supports only HR/DSSS data rates
- DD. When the Power Management bit is set to 1
- EE. When the probe request frames contain the correct SSID value
73Which of the following are true about scanning? (Choose all that apply.)
- AA. There are two types of scanning: passive and active.
- BB. Stations must transmit probe requests in order to learn about local APs.
- CC. The 802.11 standard allows APs to ignore probe requests for security reasons.
- DD. It is common for stations to continue to send probe requests after being associated to an AP.
74What process is used by band steering to make client radios connect to the AP's 5 GHz radio?
- AA. The AP disables the 2.4 GHz radio.
- BB. The AP disables the 2.4 GHz radios during the connection process.
- CC. The AP signals the client that 5 GHz connectivity is preferred, triggering the client to disable its 2.4 GHz radio.
- DD. The AP only responds to the client using the 5 GHz radio.
- EE. Band steering is enabled on the client, not the AP, requiring the client to be configured to use band steering.
75When a client station is first powered on, what is the order of frames generated by the client station and AP?
- AA. Probe request, probe response, association request/response, authentication request/response
- BB. Probe request, probe response, authentication request/response, association request/response
- CC. Association request/response, authentication request/response, probe request, probe response
- DD. Authentication request/response, association request/response, probe request, probe response
76WLAN users have recently complained about gaps in audio and problems with the push-to-talk capabilities with the ACME Company's VoWiFi phones. What could be the cause of this problem?
- AA. Misconfigured TIM setting
- BB. Misconfigured DTIM setting
- CC. Misconfigured ATIM setting
- DD. Misconfigured BTIM setting
77The WLAN help desk gets a call that all of the sudden, all of the HR-DSSS (802.11b) VoWiFi phones cannot connect to any of the ERP (802.11g) lightweight APs that are managed by a multiple-channel architecture WLAN controller. All the laptops with ERP (802.11g) radios can still connect. What are the possible causes of this problem? (Choose all that apply.)
- AA. The WLAN admin disabled the 1, 2, 5.5, and 11 Mbps data rates on the controller.
- BB. The WLAN admin disabled the 6 and 9 Mbps data rates on the controller.
- CC. The WLAN admin enabled the 6 and 9 Mbps data rates on the controller as basic rates.
- DD. The WLAN admin configured all the APs on channel 6.
78In a multiple-channel architecture, roaming is controlled by the client station and occurs based on a set of proprietary rules determined by the manufacturer of the wireless radio. Which of the following parameters are often used when making the decision to roam? (Choose all that apply.)
- AA. Received signal level
- BB. Distance
- CC. SNR
- DD. WMM access categories
79What are some of the advantages of using U-APSD and WMM-PS power management over legacy power-management methods? (Choose all that apply.)
- AA. Applications control doze time and trigger frames.
- BB. U-APSD APs transmit all voice and video data immediately.
- CC. The client does not have to wait for a beacon to request data.
- DD. Downlink traffic is sent in a frame burst.
- EE. Data frames are used as trigger frames. PS-Poll frames are not used.
80WMM-PS is based on which 802.11-2007 power-management method?
- AA. S-APSD
- BB. U-APSD
- CC. PSMP
- DD. SM Power Save
- EE. PS-Poll
81[blank_start]DLL[blank_end] - Data link Layer - has two sublayers
[blank_start]LLC[blank_end] - Logical link control - establish flow control
[blank_start]MAC[blank_end] - Media access control - mac address
[blank_start]MSDU[blank_end] - MAC service data unit - data (layer 3-7) of MAC from LLC
[blank_start]MPDU[blank_end] - MAC protocol data unit - encapsulation in MAC frame
[blank_start]PSDU[blank_end] - PLCP services data unit - same frame as MPDU
[blank_start]PPDU[blank_end] - PLCP protocol data unit - adds preamble and PHY header
[blank_start]RTS[blank_end] - request to send
[blank_start]CTS[blank_end] - clear to send
[blank_start]ACK[blank_end] - acknowledgement
[blank_start]TIM[blank_end] - traffic indication map
[blank_start]DTIM[blank_end] - delivery traffic indication message
[blank_start]ATIM[blank_end] - announcement traffic indication message- ADLL
- BLLC
- CMAC
- DMSDU
- EMPDU
- FPSDU
- GPPDU
- HRTS
- ICTS
- JACK
- KTIM
- LDTIM
- MATIM
82[blank_start]CSMA/CA[blank_end] - carrier sense multiple access w/ collision avoidance
[blank_start]CSMA/CD[blank_end] - carrier sense multiple access w/ collision detection
[blank_start]DCF[blank_end] - distributed coordination function - mandatory access mode of 802.11
[blank_start]PCF[blank_end] - point coordination function - optional access mode of 802.11
HCF - hybrid coordination function - combines DCF + PCF
HCF - hybrid coordination function
[blank_start]BA[blank_end] - block acknowledgement
[blank_start]WMM[blank_end] - Wi-Fi multimedia
[blank_start]IFS[blank_end] - interframe space - time between wireless transmissions- ACSMA/CA
- BCSMA/CD
- CDCF
- DPCF
- EBA
- FWMM
- GIFS
83[blank_start]AP[blank_end] - access points - wired hubs
IS - integration service - delivery of MSDUS between DS via portal (AP)
[blank_start]DS[blank_end] - distribution service - connects basic set of services via LAN
[blank_start]WDS[blank_end] - wireless distribution service - DS using wireless medium (bridge)
[blank_start]SSID[blank_end] - service set identifier - identifies network
[blank_start]BSS[blank_end] - basic service set
IBSS - independent basic service set
MBSS - mesh basic service set
[blank_start]BSSID[blank_end] - basic service set identifier
[blank_start]MSDU[blank_end] - MAC service data unit - upper-layer info contained in 802.11 frame
[blank_start]DSS[blank_end] - distribution system services - switch in AP or WLAN controller
BSA - basic service area
ESS - extended service set- AAP
- BDS
- CWDS
- DSSID
- EBSS
- FBSSID
- GMSDU
- HDSS
84[blank_start]FHSS[blank_end] - frequency hopping spread spectrum - transmits narrowband signal over a wide band
[blank_start]DSSS[blank_end] - direct sequence spread spectrum - transmits signal accross frequency wide range
[blank_start]ISM[blank_end] - industrial, scientific and medical band
[blank_start]UNII[blank_end] - unlicensed national information infrastructure band
[blank_start]OFDM[blank_end] - orthogonal frequency division multiplexing - divides whole bandwidth into subcarriers- AFHSS
- BDSSS
- CISM
- DUNII
- EOFDM
Información
- Descripción
- Computer Science Test sobre wireless test 2, creado por Duncan Levings el 31/10/2018.
- Autor
- Duncan Levings
- Idioma
- English
- Visitas
- 76
- Etiquetas
- Valoración
- Aún sin valoraciones Valora este test