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CCNA Wireless

Michael Gleeson CCNA Wireless English 170 cards

Cards in this deck (170)

  1. 1What is absorption?The effect of an RF signal meeting a material that absorbs or attenuates the signal strength by some amount.
  2. 2Active Scanning?A method used by Wireless Clients to actively scan for available APs by sending probe request frames
  3. 3Active Site Survey?A method used to measure wireless LAN coverage & performance by analyzing the survey device itself as it interacts with the APs as it is moved throughout an area.
  4. 4What is AQI?Air Quality Index
    A scale from 0-100 that indicates how usable an 802.11 channel is, based on the no. and intensity of interfering sources
  5. 5What is an Amplifier? What is Amplitude?Amplifier is an active device that adds gain to an RF signal
    Amplitude - The height from the top peak to the bottom peak of signals waveform
  6. 6Anchor ControllerThe original controller a client was associated with before a Layer 3 inter-controller roam occurs. An anchor controller can also be used for tunneling clients on a guest WLAN or with a static anchor. Traffic is tunneled from the clients current controller (foreign controller) back to the anchor
  7. 7AP-manager interfaceA logical link that can be configured to terminate CAPWAP tunnels from Lightweight APs
  8. 8AP-on-a-stickA site survey method used to measure the coverage area of a single AP that is mounted on a pole, latter or stick. The survey is usually performed before APs are deployed in an area.
  9. 9AssociationProcess by which Wireless device becomes a functioning member of a BSS
  10. 10Asymmetric power problemWhere AP and client use different tx power levels such that the messages sent by device 1 are received & understood by device 2. The replies from dev2 are too weak to be understood by dev1
  11. 11AttenuatorA passive device that introduces additional loss to an RF signal
  12. 12Authentication ServerAn 802.1x entity that authenticates users or clients based on their credentials, as matched against a user database. a RADIUS server is an AS
  13. 13Authenticator802.1x entity that exists as a network device that provides access to the network. WLC acts as an authenticator
  14. 14Autonomous APAP operating in standalone mode, such that it can provide a fully functional BSS and connect to the DS
  15. 15Back off timerThe random amount of time a Wireless client must wait before attempting to transmit a frame
  16. 16Barker 11 Code11-bit sequence of encoded bits that represent a single data bit
  17. 17BSSBasic Service Set
    Wireless service is provided by an AP to one or more associated clients
  18. 18BeamwidthA measure of the angle of radiation pattern in both the E & H planes, where the signal strength is 3 dB below the max value
  19. 19Block AcknowledgementA feature used by 802.11n that permits a burst of data frames to be followed by a single acknowledgement message, improving throughput
  20. 20BSS Basic RateA data rate that is required to be supported between an AP and a Wireless client
  21. 21BSSID methodAn active site survey method where the survey client is locked to a specific BSSID so that the cell of a single AP can be measured
  22. 22CAPWAP Discovery ProcessA message sent by a LAP to discover one or more WLCs. Any controllers that receive the request should return a CAPWAP Discovery Response message to the AP
  23. 23CAPWAP Join RequestA message sent by the LAP to a specific WLC indicating desire to join or associate with the controller. If the AP is accepted, the WLC returns a CAPWAP Join Response.
  24. 24Carrier SignalThe basic, steady RF signal that is used to carry other useful information
  25. 25CCX LiteCCX certification program that is organised in modules, according to specific applications for Wireless devices
  26. 26CellThe area of Wireless coverage provided by an AP; also knows as the basic service area
  27. 27CWACentral Web Authentication
    A method of wireless user authentication page and a user database that are both located centrally on a RADIUS server, rather than locally on the WLC
  28. 28CACertificate Authority
    A trusted entity that generates and signs digital certificates
  29. 29Channel ReuseThe pattern of APs and their channels, arranged such that neighbour APs never use the same channel
  30. 30ChipBit provided by a coder
  31. 31Cisco CleanAirWireless technology used to detect, classify, report & react to non 802.11 interference
  32. 32Cisco Compatibility Extensions (CCX)A wireless device certification that verifies compatibility with a set of Cisco-developed features. CCX is defined in 5 versions
  33. 33What are the 5 CCX versions and their uses?a
  34. 34CCAClear Channel Assessment
    The process a wireless device uses to determine whether the channel is clear and available to use
  35. 35Cloud-based APCisco Meraki autonomous AP that is managed in the cloud
  36. 36Cluster IDA unique identifier that a WLC assigns to a non 802.11 device found to be interfering with the AP
  37. 37CCICo Channel Interference
    RF Signal interference caused by two or more transmitters using the same frequency or channel
  38. 38CoderA function that converts data bits into multiple encoded bits before tx. To provide resilience against noise & interference.
  39. 39Collision Avoidancethe technique used by 802.11 devices to proactively avoid collisions on a channel
  40. 40CCKComplimentary Code Keying
    An encoding method that takes either 4 or 8 data bits at a time to create a 6-bit or 8-bit symbol. The symbols are fed into DQPSK to modulate the carrier signal
  41. 41Contention WindowThe range of values that a wireless station can use to compute a random back off timer duration
  42. 42Controller InterfaceA logical connection that WLC uses internally
  43. 43Controller PortA physical connection to a wired network
  44. 44What is CCMPA wireless security scheme based on 802.11i that uses AES counter mode for encryption CBC-MAC for data integrity
  45. 45Coverage HoleAn area with that is left without good RF coverage. A coverage hole can be caused by a radio failure or weak signal in the area
  46. 46dBd dBi dBm dBGain - Decibel compared to a dipole antenna
    Gain - Decibel compared to an Isotropic referenced antenna
    dBm - the power level of a signal measured in dB. Compared to signal power of 1 milliwatt
    dB - A logarithmic function that compares 1 absolute measurement to another
  47. 47DTIMDelivery Traffic Indication Map
  48. 48DBPSKDifferential Binary Phase Shift Keying
    A modulation method that takes 1 bit of encoded date and changes the phase of the carrier signal in 1 of 4 ways
  49. 49DemodulationThe rx process of interpreting changes in the carrier signal to recover the original information being sent
  50. 50DQPSKDifferential Quadrature Phase Shift Keying
    A modulation method that takes 2 bit of encoded date and changes the phase of the carrier signal in 1 of 4 ways
  51. 51DiffractionThe effect of an RF signal approaching an opaque object causing the wave to bend round the object
  52. 52DipoleOmnidirectional antenna composed of two wire segments
  53. 53DSSSDirect Sequence Spread Spectrum
    a WLAN method where a tx uses a single fixed, wide channel to send data
  54. 54Directional AntennaA type of antenna that propagates an RF signal in a narrow range of directions
  55. 55DCFDistrubuted Co-ordinated Function
    The method used by each wireless device to co-ordinate the wireless channel
  56. 56How does DCF work?a
  57. 57DSDistribution System
    The wired ethernet that connects to an AP and transports traffic between a wired and wireless network
  58. 58Distribution Sytem PortA Physical interface that connects a WLC to a switched network and carries both AP & management traffic
  59. 59Duty CycleA measure of the percentage time a device transmits on a given frequency
  60. 60DCADynamic Channel Allocation
    An RRM algorithm that monitors APs in an RF group and adjust their channel assignment based on poor RF conditions
  61. 61Dynamic InterfaceAn internal logical link that connects a VLAN to a WLAN. Traffic passing through a dynamic interface also passes through a VLAN on a distribution port
  62. 62DRSDynamic Rate Shifting
    A mechanism used by an 802.11 device to change the MCS < what is this? Modulation Coding Scheme according to dynamic RF signal conditions
  63. 63EAP - FASTExtensible Authentication Protocol
    Flexible Authentication by Secure Tunneling
    A Cisco authentication method that is based on EAP and uses a PAC as a credential for outer authentication & a TLS tunnel for inner authentication
  64. 64EAP-TLSTransport Layer Security
    An authentication method that uses digital certificate on both the server & the supplicant for mutual authentication. A TLS Tunnel is used during client authentication and key exchanges
  65. 65EIRPEquivalent Isotropically Radiated Power
    The resulting signal power level, measure in dBm, the combination of a tx cable, cable, antenna, as mesaured at the antenna
  66. 66Enterpise mode802.1x EAP based authentication requirement WPA or WPA2
  67. 67E PlaneElevation plane passing through an antenna that shows a side view of the radiation pattern
  68. 68ED-RRMEvent Driven - Radio Resource Mgmt
    Using Cisco CleanAir to trigger the RRM DCA process automatically, as interference is detected
  69. 69ESSExtended Service Set
    Multiple APs that are connected by a common switch infrastructure
  70. 70Foreign ControllerThe current controller a client is associated with after a layer 3 intercoller roam occurs. Traffic is tunneled from the foreign controller back to an anchor controller so that the client retains connectivity to its original VLAN and subnet
  71. 71FSPLFree Space Path Loss
    The degradation of an RFs signal strength as it travels through free space
  72. 72FrequencyThe number of times a signal makes one complete up & down cycle in a second
  73. 73FHSSFrequency Hopping Spread Spectrum
    A WLAN method where a transmitter 'hops' between frequencies across a band
  74. 74Fresnel ZoneThe elliptical shaped space between a tx & rx that must be kept clear of objects, else the RF signal will be degraded
  75. 75GainA Measure of how effectively an antenna can focus RF energy in a certain direction
  76. 76GIGuard Interval
    The amount of time required between OFDM symbols to prevent inter symbol interference
  77. 77What is the standard GI time and what can it be reduced to?800 ns
    reduced to 400 ns
  78. 78Hertz HzA Unit of frequency equaling one cycle per second
  79. 79H Plane, what is it also called?AKA Azimuth plane. Passing through an antenna that shows a top-down view of the radiation pattern
  80. 80in phasethe condition when the cycles of two identical signals are in sync with each other
  81. 81IBSSIndependent Basic Service Set
    An impromptu wireless network formed between two or more devices without an AP or a BSS; aka ad hoc network
  82. 82Infrastructure ModeThe operating mode of an AP that is providing a BSS for wireless clients
  83. 83Intercontroller RoamingClient roaming that occurs between two APs that are joined to two different controllers
  84. 84Interframe Spacethe amount of time the 802.11 standard defines to separate adjacent frames on a channel
  85. 85ISIInter Symbol Interference
    Data corruption caused by OFDM symbols arriving too close together at a receiver, usually caused by signals that take different paths from tx to rx
  86. 86Intracontroller RoamingClient roaming that occurs between two APs joined to the same controller
  87. 87Isotropic AntennaAn ideal, theoretical antenna that radiates RF equally in every direction
  88. 88Layer 2 RoamAn intercontroller roam where the WLANs of the two controllers are configured for the same L2 VLAN ID;AKA local-to-local roam
  89. 89Layer 3 RoamAn intercontroller roam where the WLANs of the two controllers are configured for different VIDs. AKA local-to-foreign roam. To support the roaming client, a tunnel is built between controllers so that client data can pass between the clients current WLC and its orginal WLC
  90. 90Lightening ArrestorA device used to protect a tx or rx from large transient voltages that might be included by lightening around an atenna
  91. 91LEAPLightweight EAP
    A legacy Cisco wireless security method
  92. 92LAGLink Aggregation Group
    A grouping or bundling of multiple physical links into a single logical link
  93. 93Link Budgetthe cumulative sum of gains and losses measured in dB over the complete RF signal path; a tx power level must overcome the link budget so that the signal can reach a receiver effectively
  94. 94LWALocal Web Authentication
    A method of wireless user authentication that occurs locally on a WLC through the use of local user accounts and a web portal
  95. 95MFPManagement Frame Protection
    Method developed by Cisco to protect wireless clients and APs from attacks involving spoofed mgmt frames
  96. 96Management InterfaceA logical link that is used for normal management traffic. If an AP-manager interface is not configured, the mgmt interface also terminates CAPWAP tunnels from Aps
  97. 97Mandatory Data Ratean 802.11 data rate that must be supported by a client before it can associate to an AP
  98. 98MRCMaximal Ratio Combining
    802.11 technique that takes multiple copies fo a signal, received over multiple antennas, and combines them to reconstruct the original signal
  99. 99MICMessage Integrity Check
    A cryptographic value computed from the contents of a data frame and used to detect tampering
  100. 100MAMobility Agent
    A WLC function that terminates CAPWAP tunnels from APs, as well as maintains a client database and enforces security and QoS policies
  101. 101Mobility AnchorA WLAN controller acts as the anchor or home base for remote wireless clients that are joined to a different controller
  102. 102MCMobility Controller
    a WLC function that manages one or more MAs, handles RRM, performs WIPS, and manages guest access
  103. 103mobility domaina logical grouping of all mobility groups within an enterprise
  104. 104mobility groupa logical grouping of one or more MCs between which efficient roaming is expected
  105. 105mobility subdomainA logical grouping of one MC along with the MAs relying on the MC for roaming efficiency
  106. 106modulationthe tx process of altering the carrier signal according to some other information source
  107. 107mono poleA very short omni-directional antenna composed of a single wire segment set over a metal ground plane
  108. 108MultipathReflected copies of an RF signal arrive at a receiver after taking different paths through free space
  109. 109N+1 RedundancyHigh availability offered by N number of active controllers plus one idle standby controller
  110. 110N+N redundancyHigh availability offered by N number of active controllers. The AP load is distributed across the active controllers, so no additional backup controller
  111. 111N+N+1 redundancyHigh availability offered by N number of active controllers plus one idle standby controller
  112. 112NAVNetwork Allocation Vector
    An internal timer maintained by each wireless device that measures the number of timeslots before a transmission may be attempted
  113. 113Noise floorThe average power level of noise measured at specific frequency
  114. 114NDP (Null Data Packet)The explicit method for transmit beamforming specified by the 802.11ac amendment
  115. 115Omnidirectional AntennaType of antenna that propogates an RF signal in a broad range of directions in order to cover a large area
  116. 116Open authentication802.11 authentication method that requires clients to associate with an AP without providing any credentials at all
  117. 117Open System AuthenticationA simple method used to verify that a wireless device uses 802.11 before it i permitted to join a BSS
  118. 118OFDMOrthogonal Frequency Division Multiplexing
    A data transmission method that sends data bits in parallel over multiple frequencies within a single 20 MHz wide channel. Each frequency represents a single subcarrier
  119. 119Out of phaseThe condition when the cycles of one signal are shifted in time in relation to another signal
  120. 120Parabolic DishA highly directional antenna that uses a passive dish shaped like a parabola to focus an RF signal into a tight beam
  121. 121Passive scanningA method used to scan for available APs by listening to their beacon frames
  122. 122Patch AntennaA directional antenna that has planar surface and is usually mounted on a wall or column
  123. 123Personal ModePre-shared key authentication as applied to WPA or WPA2
  124. 124PhaseA measure of shift in time relative to the start of a cycle; ranges between 0 and 360 degrees
  125. 125Physical Carrier SenseTo determine whether a channel is available, a device simply listens to any signals that might be present
  126. 126P2P BridgePoint to Point Bridge
    An AP configured to bridge a wired network to a companion bridge at the far end of a line-of-sight path
  127. 127PoAPoint of Attachment
    The controller that anchors a clients IP address for Layer 3 roaming
  128. 128PoPPoint of Presence
    The controller where a client is currently associated
  129. 129PolarizationThe orientation (horizontal, vertical, circular, and so on) of a propagating wave with respect to the ground
  130. 130Primed controller addressThe name of IP address of a controller that is configured in advance on an AP
  131. 131PACProtected Access Credential
    Special-purpose data that is used as an authentication credential in EAP-FAST
  132. 132PEAPProtected EAP
    An authentication method that uses a certificate on the AS for outer authentication and a TLS tunnel for inner authentication. Clients can provide their credentials thorough either MS-CHAPv2 or GTC
  133. 133What is MS-CHAP & GTC?a
  134. 134PMFProtected Management Frames
    A service provided by 802.11w that protects a set of 802.11 Robusr Management Frames and Robust Action Frames
  135. 135Protection MechanismA method of supporting backward compatibility between an advanced and a legacy wireless standard, such as 802.11g and 802.11b, respectively. For example, each 802.11g OFDM transmission is flagged with RTS/CTS messages sent in the lower-rate of DSSS format
  136. 136Pseudo-MAC addressA virtual MAC address that a controller assigns to each uniquely identified non-802.11 interferer so that it can be reported and displayed
  137. 137PKIPublic Key Infrastructure
    An enterprise-wide system that generates and revokes digital certificates for client authentication
  138. 138QAMQuadrature Amplitude Modulation
    A modulation method that combines QPSK phase shifting with multiple amplitude levels to produce a greater number of unique changes to the carrier signal. The number preceding the QAM name designates how many carrier signal changes are possible
  139. 139Re-associationThe process by which a wireless client changes its association from BSS to another as it moves
  140. 140RefractionThe effect of an RF signal meeting the boundary between two different materials, causing its trajectory to change slightly
  141. 141RF GroupA logical grouping of WLANs that operates as a single RF domain. RRM Algorithms run on a per-RF group basis
  142. 142RF group leaderA controller that is elected to handle all of the RRM algorithms for the entire RF group
  143. 143RRMRadio Resource Management
    A set of algorithms that is used to maintain a stable and optimum wireless network even in a changing RF environment
  144. 144Sensitivity levelThe RSSI threshold (in dBm) that devides unintelligible RF signals from useful ones
  145. 145Service portA physical non trunking port interface that connects a wireless controller to a switched network and carries only out-of -band management traffic
  146. 146Shared Key AuthenticationMethod used to authenticate a wireless device with a BSS by WEP key
  147. 147SNRSignal To Noise Ratio
    A measure of received signal quality, calculated as the difference between the signals RSSI and the noise floor. A higher SNR is preffered
  148. 148Spatial MultiplexingDistributing streams of data across multiple radio chains with spatial diversity
  149. 149Spatial StreamAn independent stream of data that is sent over a radio chain through free space. One spatial stream is separate from others due to the unique path is travels through space
  150. 150SSID methodAn active site survey method where the survey client associates to a specific SSID on any AP
  151. 151SSOStateful Switch Over
    High availability offered by controllers configured as fail-over pair. One controller is active and supports the AP & client load, while the other WLC is a hot standby. Stateful info about APs & clients in the RUN state is synchronized between the active & standby units for an efficient failover
  152. 152Supplicantan 802.11x entity that exists as software on a client device and serves to request network access
  153. 153SPG (Switch peer group)A logical grouping of MA's between which frequent and efficient roaming is expected
  154. 154symbolA complete group of encoded chips that represent a data bit
  155. 155TKIPTemporal Key Integrity Protocol
    A wireless security scheme developed before 802.11i that provides a MIC for data integrity, a dynamic method for per-frame WEP encryption keys, and a 48-bit initialisation vector. the MIC also includes a time stamp & the senders MAC address
  156. 156TPCTransmit Power Control
    Mechanism used to reduce the power of a radio transmitter to the minimum necessary to maintain the link with a certain quality. TPC is used to avoid interference into other devices and/or to extend the battery life.
  157. 157TIMTraffic Indication Map
    A list of the association IDs of wireless clients who are in a power save mode but have frames buffered. The TIM is included in beacon frames sent by an AP
  158. 158TxBFTransmit Beamforming
    An 802.11n method to tx a signal over multiple antennas, each having the signal phase carefully crafted, so that the multiple copies are all in phase at a targeted receiver
  159. 159U-APSDUninterupted-Automatic Power Save Deliver
    The method defined in 802.11e & WMM that allows a wireless client to enter power save mode and then have buffered frames delivered whenever the client is ready to receive them
  160. 160Virtual carrier senseThe method by which a wireless device calculates that a channel is available, based on frame duration information that is used to set the NAV
  161. 161Virtual interfaceA logical link used to support wireless clients with things like DHCP relay and web authentication
  162. 162WavelengthThe physical distance that a wave travels over one complete cycle
  163. 163WPAWi-Fi Protected Access
    A Wi-Fi alliance standard that requires pre-shared key or 802.1x authentication, TKIP, and dynamic encryption key management; based on portions of 802.11i before its ratification
  164. 164WCMWireless Control Module
    A wireless controller function that is built into an access layer switch, forming the basis o a converged wireless network
  165. 165WEPWireless Equivalent Privacy
    An 802.11 authentication and encryption method that requires clients and APs to use a common WEP key
  166. 166WIPSWireless Intrusion Protection System
    A system that monitors wireless activity to detect malicious behaviour according to a set of signatures or patterns
  167. 167WMMWireless Multimedia
    A Wi-Fi alliance interoperability certification that covers QoS (Quality of Service) and enhanced power save delivery methods
  168. 168WGBWorkgroup Bridge
    An AP that configured to bridge between a wired device and a wireless network. The WGB acts as a wireless client
  169. 169WPA2Wireless Protected Access Version 2
    A Wi-Fi alliance standard that requires pre-shared key or 802.1x authentication, TKIP or CCMP, and dynamic encryption key management; based on the complete 802.11i standard after its ratification
  170. 170Yagi AntennaA directional antenna made up of several parallel wire segments that tend to amplify an RF signal to each other

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CCNA Wireless Flashcards on CCNA Wireless, created by Michael Gleeson on 14/11/2017.
Created by
Michael Gleeson · Nov 2017
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Nov 19, 2017
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