Wireless Standards And Protocols Test For Beginners!

180 Questions | Total Attempts: 96

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Protocol Quizzes & Trivia

Questions and Answers
  • 1. 
    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? 
    • A. 

      A single AP supports multiple BSSs with different SSIDs

    • B. 

      The beacons are from an IBSS instead of a BSS

    • C. 

      A virtual cell single channel network has been implemente

    • D. 

      Three APs still share the same default configuration.

  • 2. 
    When compared with legacy Power Save mode, how does VHT TXOP power save improve battery life for devices on a WLAN?   
    • A. 

      VHT TXOP power save allows stations to enter sleep mode and legacy Power Save does not.

    • B. 

      Legacy Power Save mode was removed in the 802.11ac amendment

    • C. 

      VHT TXOP power save uses the partial AID in the preamble to allow clients to identify frames targeted for them.

    • D. 

      VHT TXOP power save allows the WLAN transceiver to disable more components when in a low power state.

  • 3. 
    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? 
    • A. 

      Client devices ignore the TIM field and automatically send PS-Poll frames after every beacon

    • B. 

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

    • C. 

      After each beacon, the AP attempts to empty its frame buffer by sending Wake-on-WLAN frames to wake each dozing client

    • D. 

      Request-to-Send and Clear-to-Send frame exchanges are used to trigger the delivery of buffered data.

    • E. 

      The Beacon interval is changed from the default 100 time units to 10 or less time units.

    • F. 

      Stations send a CTS-to-self frame to the AP with a very long duration period so they can receive all of their buffered data at once.

  • 4. 
    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) _________. 
    • A. 

      MAC Protocol Data Unit (MPDU)

    • B. 

      MAC Service Data Unit (MSDU)

    • C. 

      IP datagram

    • D. 

      PLCP Service Data Unit (PSDU)

    • E. 

      PLCP Protocol Data Unit (PPDU)

  • 5. 
    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 ____________. 
    • A. 

      Frames

    • B. 

      Packets

    • C. 

      Symbols

    • D. 

      Bytes

    • E. 

      Bits

  • 6. 
    Prior to association, what parameter can 802.11 client devices measure and use to select the optimal access point for association?
    • A. 

      Proximity to potential access points

    • B. 

      Signal strength of access point beacons received

    • C. 

      Retry rate of probe request and response frames

    • D. 

      Average round trip time to reach the Internet DNS server

    • E. 

      Average round trip time to reach the IP router

  • 7. 
    In an infrastructure Basic Service Set (BSS), how does the passive scanning process occur? 
    • A. 

      Client stations broadcast Probe Request frames on all supported channels in the regulatory domain. Nearby access points respond with Probe Response frames. Client stations record information in the Probe Response frames for use in the association process.

    • B. 

      Client stations broadcast Probe Request frames on the single channel for which they are programmed. Nearby access points respond on that channel with Probe Response frames. Client stations record information found in the Probe Response frames for use in the association process

    • C. 

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

    • D. 

      Access points broadcast Beacons on all channels of each radio within the regulatory domain. Nearby client stations record information found in the Beacons for use in the association process.

  • 8. 
    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? 
    • A. 

      During the association, the client and AP agree to use the same transmit rate, but either station can request a change at any time after the association.

    • B. 

      The client and AP may use different transmit rates, but the AP determines the data rate that will CWNA CWNA-106 Exam "Pass Any Exam. Any Time." - www.actualtests.com 24 be used by each client station in the BSS

    • C. 

      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.

    • D. 

      The client and AP may use a different transmit rates, but the transmit rate is determined by the peer station, based on the peer’s experience of the RF link.

    • E. 

      The client and AP may use a different transmit rates, but the transmit rate is determined by the peer station, based on the peer’s experience of the RF link.

  • 9. 
    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? 
    • A. 

      Multirate Control

    • B. 

      Modulation and Coding Selection

    • C. 

      Rate Set Selectivity

    • D. 

      Dynamic Rate Switching

    • E. 

      Adaptive Rate Management

  • 10. 
    What statement about the IEEE 802.11e QoS facility is true? 
    • A. 

      When the Voice queue has frames awaiting transmission, no data will be transmitted from the Best Effort queue.

    • B. 

      To improve efficiency, Block Acknowledgments are required for Voice and Video WMM queues

    • C. 

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

    • D. 

      Four 802.1p user priorities are mapped to eight 802.11 transmit queues.

    • E. 

      802.11 control frames are assigned to the 802.11 EF priority queue.

  • 11. 
    What distinguishes an independent basic service set (IBSS) from an infrastructure basic service set (BSS)? 
    • A. 

      An IBSS does not require beacon frames, but a BSS does.

    • B. 

      An IBSS does not support 802.11 authentication or association, but a BSS does

    • C. 

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

    • D. 

      An IBSS does not support any 802.11ac enhancements, but a BSS does.

  • 12. 
    What statements about the SSID are true?  (Choose 2) 
    • A. 

      When configuring a new network, creating an SSID is optional.

    • B. 

      The SSID must be included in an association request frame.

    • C. 

      The SSID is an alphanumeric value assigned to device manufacturers by the IEEE.

    • D. 

      The SSID is an alphanumeric value with a maximum length of 32 octets.

    • E. 

      The SSID is a security session identifier used in RSNs.

  • 13. 
    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? 
    • A. 

      The current AP is using channel 1 and the new AP is using channel 40.

    • B. 

      The current AP supports only HT and the new AP is VHT capable.

    • C. 

      The SSID of the current AP does not match the SSID of the new AP.

    • D. 

      The access points are hiding the SSID in Beacons and Probe Response frames.

  • 14. 
    When a client moves to a new BSS within an ESS, what steps are part of the 802.11 reassociation process?  (Choose 2) 
    • A. 

      The current access point informs the IP gateway of the reassociation

    • B. 

      The current access point triggers the client’s reassociation service.

    • C. 

      The new access point transmits a Reassociation Response to the client station with a status value.

    • D. 

      The client and new access point create unicast encryption keys.

    • E. 

      The client station transmits a deauthentication frame to the current access point.

    • F. 

      The client station transmits a Reassociation Request frame to its current access point.

  • 15. 
    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? 
    • A. 

      This client device supports both TKIP and CCMP cipher suites.

    • B. 

      This client device supports protection mechanisms such as RTS/CTS and/or CTS-to-Self.

    • C. 

      300 Mbps is the maximum supported data rate for this device.

    • D. 

      This client device supports the ERP, OFDM, and HT physical layer specifications.

    • E. 

      This client device supports X.509 certificates for EAP authentication.

  • 16. 
    Which data rate is supported by 802.11g radios that is not supported by 802.11a radios? 
    • A. 

      9 Mbps

    • B. 

      12 Mbps

    • C. 

      11 Mbps

    • D. 

      54 Mbps

    • E. 

      65 Mbps

    • F. 

      130 Mbps

  • 17. 
    Which of the following frequency ranges are specified for use by IEEE 802.11 radios? (Choose all that apply.)
    • A. 

      902 - 928 MHz B

    • B. 

      2.4000 – 2.4835 GHz

    • C. 

      5.15 – 5.25 GHz

    • D. 

      5.470 – 5.725 GHz

    • E. 

      5.725 – 5.875 GHz

  • 18. 
    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? (Choose 2)   
    • A. 

      PLCP

    • B. 

      IP

    • C. 

      MAC

    • D. 

      . Transport

    • E. 

      Network

    • F. 

      . PPDU

  • 19. 
     What features were introduced in the IEEE 802.11h amendment in order to uphold regulatory requirements for 5 GHz operation?  (Choose 2) .
    • A. 

      . Radio Resource Management (RRM)

    • B. 

      . Phase Shift Keying (PSK)

    • C. 

      Dynamic Frequency Selection (DFS)

    • D. 

      . Transmit Power Control (TPC)

    • E. 

      256-QAM

    • F. 

      Distributed Coordination Function (DCF)

  • 20. 
    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? 
    • A. 

      14 channels are available worldwide

    • B. 

      DFS may be required in some regulatory domains on some channels

    • C. 

      Regulatory domains worldwide require DFS and TPC in all these channels.

    • D. 

      11 channels are available worldwide.

    • E. 

      802.11 channels are separated by 5 Mhz

  • 21. 
    When a client station sends a broadcast probe request frame with a wildcard SSID, how do APs respond? 
    • A. 

      After waiting a SIFS, a designated AP sends an ACK, and then replies with a probe response.

    • B. 

      For each probe request frame, only one AP may reply with a probe response

    • C. 

      Each AP checks with the DHCP server to see if it can respond and then acts accordingly

    • D. 

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

    • E. 

      After waiting a SIFS, all APs reply at the same time with a probe response.

  • 22. 
    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?  (Choose 2)
    • A. 

      . Radio receiver hardware cannot process data as quickly as it can be transmitted.

    • B. 

      WLAN devices cannot detect collisions and must receive positive frame acknowledgment

    • C. 

      . Half of the bandwidth is allocated to uplink traffic and half to downlink traffic

    • D. 

      . APs do not have sufficient wired connection speeds to the LAN.

    • E. 

      The DCF and EDCA coordination functions require backoff algorithms

  • 23. 
    What answers correctly complete the following sentence? ____________ and ____________ carrier sense functions are used to determine if the wireless medium is busy. (Choose 2) 
    • A. 

      Backoff

    • B. 

      Pseudo-random

    • C. 

      Virtual

    • D. 

      Active

    • E. 

      Vector

    • F. 

      . Physical

    • G. 

      Interframe

  • 24. 
    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
    • A. 

      2.427 GHz

    • B. 

      2.422 GHz

    • C. 

      2.437 GHz

    • D. 

      2.417 GHz

    • E. 

      2.413 GHz

  • 25. 
    What facts are true regarding controllers and APs in a Split MAC architecture? (Choose 2)   
    • A. 

      With 802.1X/EAP security, the AP acts as the supplicant and the controller acts as the authenticator

    • B. 

      An IP tunnel is established between the AP and controller for AP management and control functions.

    • C. 

      Using centralized data forwarding, APs never tag Ethernet frames with VLAN identifiers or 802.1p CoS.

    • D. 

      Management and data frame types must be processed locally by the AP, while control frame types must be sent to the controller.

    • E. 

      In a distributed data forwarding model, the AP handles frame encryption and decryption.

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