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CWNA 802.11 Mac Architecture

Subjects : cisco, it-skills, cwna
Instructions:
  • Answer 46 questions in 15 minutes.
  • If you are not ready to take this test, you can study here.
  • Match each statement with the correct term.
  • Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. Help with the delivery of data frames. Control frames must be able to be heard by all stations; therefore - they must be transmitted at one of the basic rates. Control frames are also used to clear the channel - acquire the channel - and provide unic






2. When a client station decides to roam to a new AP - it will send a reassociation request frame to the new AP. It is called a reassociation not because it is reassociating to the AP - but because it is reassociating to the SSID of the wireless network






3. The lower portion of the Physical layer. the PMD sublayer modulates and transmits the data as bits






4. A bit in the 802.11 MAC header that is used by the client station to notify the AP that the station is going into Power Save Mode






5. A notification frame used to terminate an authentication. Because authentication is prerequisite for association - disassociation will also occur. Deauthentication cannot be refused by either party






6. A special type of TIM that is used to ensure that all stations are awake when multicast or broadcast traffic is sent






7. The MSDU contains data from the LLC and Layers 3-7. A simple definition of the MSDU is the data payload that contains the IP packet plus some LLC data






8. One of the most important 802.11 frame types. Commonly referred to as the beacon. Beacons are essentially the heartbeat of the wireless network. They are sent only by the AP of a BSS. Client stations transmit beacons only when participating in an IBS






9. An enhanced power-MGMT method introduced by IEEE 802.11e amendment. The Wi-Fi Alliance's WMM power save (WMM-PS) certification is based on U-APSD






10. Is the simpler of the two 802.11 authentication methods. It provides authentication without performing any type of client verification. It is essentially an exchange of hellos between the client and the AP.






11. In order for a station to be able to connect to an AP - it needs to first discover an AP. Passive scanning involves the client station listening for beacon frames that are continuously being sent by the AP.






12. An enhanced power-management method introduced by 802.11e amendment.






13. Variable-length fields that are optional in the body of management frame






14. Majority of the frame types in an 802.11 network. Used by wireless stations to join and leave the network. Another name is Management MAC Protocol Data Unit MMPDU. Mgmt frames do not carry any upper-layer info. There is no MSDU encapsulated in the MM






15. Unit of data at the Data-Link Layer






16. Probe request with specific SSIC






17. The upper portion of the physical layer. PLCP prepares the frame for transmission by taking the frame from the MAC sublayer and creating the PLCP Protocol Data Unit (PPDU)






18. A mechanism that performs a NAV distribution and helps to prevent collisions from occurring. This NAV distribution reserves the medium prior to the transmission of the data frame. RTS/CTS can be used to discover hidden node problems. RTS/CTS is one o






19. The upper portion of the Data-link layer is the IEE 802.2 Logical Link Control (LLC) sublayer - which is identical for all 802-based networks - although not used by all IEEE 802 networks.






20. When the PLCP receives the PSDU - it prepares it to be transmitted and creates the PPDU. The PLCP adds the preamble and PHY header to the PSDU






21. Carry the actual data that is passed down from the higher-layer protocols






22. An 802.11 frame. The components include a MAC header - an MSDU (Data Payload) and the trailer






23. Enables delivery of MSDU's between the distribution system (DS) and a non-IEEE-802.11 LAN via a portal






24. The set of data rates that a client station must be capable of communicating with in order to successfully associate with an AP. Basic rates are required rates with a BSS.






25. MGMT frame that is transmitted during active scanning. A client station that is looking for an SSID sends a probe request. AP's that hear the probe request will send a probe response - notifying the client of the AP presence. If a client station rece






26. Any time a station associates to an AP - the station receives an AID. The AP uses this AID to keep track of the stations that are associated and the members of the BSS.






27. Prob request management frame with no SSID information






28. A unicast frame that is used in an IBSS network when Power Save Mode is enabled. If a station has buffered data for another station it will send an ATIM frame to the other station - informing it that it must stay awake until the next ATIM window so t






29. Power MGMT method defined for use by HT radios. PSMP is an extension of automatic power save delivery (APSD) that was defined by the 802.11e amendment






30. After a station has authenticated with the AP the next step is for it to associate with the AP. When a client station associates - it becomes a member of a BSS. Association means that the client station can send data through the AP and on to the Dist






31. More complexed of the two 802.11 Auth methods. Shared Key authentication uses WEP to authenticate client stations and requires that a static WEP key be configured on both the station and the AP. In addition to WEP being mandatory - authentication wil






32. Used when stations have enabled power save mode. The TIM is a list of all stations that have undelivered data buffered on the AP waiting to be delivered. Every beacon will include the AID of the station until the data is delivered.






33. Power-saving mechanism used to allow a MIMO 802.11n device to power down all but one of it's radios






34. In order for a station to be able to connect to an AP - it needs to first discover an AP. Active scanning is one of the methods that stations use to discover AP's. The station and access point will exchange probe requests and probe responses to estab






35. A protection mechanism for mixed-mode environments. One of the benefits of using CTS-to-self over RTS/CTS as a protection mechanism is that the throughput will be higher. Because there are fewer frames being sent






36. An enhanced power MGMT method introduced by the IEEE 802.11e amendment






37. Authentication is the verification of user identity and credentials. Users must ID themselves and present credentials such as usernames and passwords or digital certificates. More-secure authentication systems exist that require multifactor authentic






38. The Wi-Fi alliance oversees the WMM-PS (Power Save) certification - which uses 802.11e mechanisms to increase the battery life via advanced power-saving mechanisms. The Wi-Fi Alliance's WMM Power Save certification is based on automatic power save de






39. Optional mode for 802.11 stations. A wireless station can shut down some of the transceiver components for a period of time to conserve power. The station indicates that it is using Power Save Mode by changing the value of the Power Mgmt field to 1






40. Equivalent to the MPDU. The MAC layer referes to the frame as the MPDU - while the Physical layer refers to this same exact frame as the PSDU






41. A short gap or period of time that is used during transmission of data






42. MGMT frame that is transmitted during active scanning. After a client station sends a probe request AP's that hear the probe request will send a probe response - notifying the client of the AP's presence. The information that is contained inside the






43. The extra characters added to a frame and used for error detection and correction






44. Default power management mode for most 802.11 stations. When a station is set for active mode - the wireless station is always ready to transmit or receive data. Active mode is sometimes referred to as Continuous aware mode - and it provides no batte






45. A notification frame used to terminate an association. A polite way of terminating the association. Disassociation cannot be refused by either party






46. Fixed-length mandatory fields in the body of management frame.