Term
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Definition
| After a L3 intercontroller roam, the client is associated to a new 'foreign' WLC. The client retains connectivity to its original VLAN and subnet. |
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Term
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Definition
| Degradation of an RF signal as it travels through free space |
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Term
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Definition
| The number of times a signal makes one complete up and down cycle in 1 second. |
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Term
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Definition
| Frequency Hopping Spread spectrum |
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Term
| Describe FHSS and which 802.11 version requires it |
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Definition
| 802.11n When a transmitter hops between frequencies all across a band |
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Term
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Definition
| The elliptical space between a transmitter and receiver that must be kept clear of objects. Otherwise the RF signal will be degraded. |
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Term
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Definition
| How effectively an antenna can focus RF energy in a certain direction |
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Term
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Definition
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Term
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Definition
| The time required between OFDM symbols to prevent intersymbol interference. |
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Term
| Length of guard interval in 802.11n |
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Definition
| In 802.11n the GI can reduced from 800 ns to 400 ns. |
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Term
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Definition
| one cylce per second when measuring a frequency |
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Term
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Definition
| 802.11n used to scale performance to a maximum of 600 Mbps |
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Term
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Definition
| The azimuth plane. Shows a top-down view of the radiation pattern |
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Term
| What is a in phase signal |
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Definition
| When the cycles of two identical signals are in sync with each other |
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Term
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Definition
| Independent basic service set - the term for a Ad hoc network |
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Term
| Independent basic service set (IBSS) |
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Definition
| A impromptu wireless network created without an AP or a BSS.(AKA Ad hoc network) |
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Term
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Definition
| When a AP provids a BSS for wireless clients |
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Term
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Definition
| Client roaming between APs that are joined to two different controllers |
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Term
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Definition
| The amount of time required by standards to separate adjacent frames on a channel |
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Term
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Definition
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Term
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Definition
| Data corruption caused by OFDM symbols arriving too close together at a receiver. |
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Term
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Definition
| Usually caused by signals that take different paths from transmitter to receiver. E.x. lag time between scattered signles reaching recever |
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Term
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Definition
| Client roaming that occurs between two APs joined to the SAME controller (Intra-controller) |
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Term
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Definition
| Cisco software which finds an autonomous APs IP address and can set its IP address and SSID |
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Term
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Definition
| An ideal, theoretical antenna that radiates RF equally in every direction. (does not exist in reality) |
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Term
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Definition
| An intercontroller roam where the WLANs of the two controllers are configured for the same Layer 2 VLAN ID; also known as a local-to-local roam. |
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Term
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Definition
| An intercontroller roam where the WLANs of the two controllers are configured for different VLAN IDs; also known as a local-to-foreign roam. To support the roaming client, a tunnel is built between the controllers so that client data can pass between the client?s current controller and its original controller. |
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Term
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Definition
| A legacy Cisco proprietary wireless security method |
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Term
| Link aggregation group (LAG) |
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Definition
| A grouping or bundling of multiple physical links into a single logical link |
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Term
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Definition
| The cumulative sum of gains and losses measured in dB over the complete RF signal path; a transmitter?s power level must overcome the link budget so that the signal can reach a receiver effectively |
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Term
| Management frame protection (MFP) |
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Definition
| A method developed by Cisco to protect wireless clients and APs from attacks involving spoofed management frames |
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Term
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Definition
| A logical link that is used for normal management traffic. If an AP-manager interface is not configured, the management interface also terminates CAPWAP tunnels from APs. |
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Term
| Maximal-ratio combining (MRC) |
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Definition
| An 802.11n technique that takes multiple copies of a signal, received over multiple antennas, and combines them to reconstruct the original signal. |
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Term
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Definition
| A network of APs used to cover a large area without the need for wired Ethernet cabling; client traffic is bridged from AP to AP over a backhaul network |
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Term
| Message integrity check (MIC) |
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Definition
| A cryptographic value computed from the contents of a data frame and used to detect tampering. |
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Term
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Definition
| A wireless LAN controller that acts as the anchor or home base for remote wireless clients that are joined to a different controller |
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Term
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Definition
| A logical grouping of controllers that facilitates efficient client roaming and mobility |
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Term
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Definition
| The transmitter?s process of altering the carrier signal according to some other information source |
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Term
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Definition
| A very short omnidirectional antenna composed of a single wire segment set over a metal ground plane |
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Term
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Definition
| Reflected copies of an RF signal arrive at a receiver after taking different paths through free space |
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Term
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Definition
| High availability offered by N number of active controllers plus one idle standby controller. |
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Term
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Definition
| High availability offered by N number of active controllers. The AP load is distributed across the active controllers, so no additional backup controller is used. |
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Term
|
Definition
| High availability offered by N number of active controllers plus one idle standby controller. |
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Term
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Definition
| RF signals that use a very narrow range of frequencies |
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Term
| Neighboring channel interference |
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Definition
| RF signal interference caused by two or more transmitters using channels that are different, but do not completely overlap |
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Term
| Network allocation vector (NAV) |
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Definition
| An internal timer maintained by each wireless device that measures the number of timeslots before a transmission may be attempted |
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Term
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Definition
| Signals or RF energy that do not come from 802.11 sources |
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Term
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Definition
| The average power level of noise measured at a specific frequency |
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Term
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Definition
| A type of antenna that propagates an RF signal in a broad range of directions in order to cover a large area |
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Term
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Definition
| An 802.11 authentication method that requires clients to associate with an AP without providing any credentials at all |
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Term
| Open system authentication |
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Definition
| A simple method used to verify that a wireless device uses 802.11 before it is permitted to join a BSS |
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Term
| Orthogonal frequency-division multiplexing (OFDM) |
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Definition
| 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. |
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Term
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Definition
| The condition when the cycles of one signal are shifted in time in relation to another signal |
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Term
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Definition
| A highly directional antenna that uses a passive dish shaped like a parabola to focus an RF signal into a tight beam |
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Term
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Definition
| A method used to scan for available APs by listening to their beacon frames |
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Term
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Definition
| A directional antenna that has a planar surface and is usually mounted on a wall or column |
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Term
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Definition
| Pre-shared key authentication as applied to WPA or WPA2 |
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Term
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Definition
| A measure of shift in time relative to the start of a cycle; ranges between 0 and 360 degrees |
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Term
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Definition
| To determine whether a channel is available, a device simply listens to any signals that might be present. |
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Term
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Definition
| An AP configured to bridge a wired network to a companion bridge at the far end of a line of sight path |
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Term
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Definition
| A round graph that is divided into 360 degrees around an antenna and into concentric circles that represent decreasing dB values. The antenna is always placed at the center of the plot. |
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Term
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Definition
| The orientation (horizontal, vertical, circular, and so on) of a propagating wave with respect to the ground |
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Term
| Primed controller address |
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Definition
| The name or IP address of a controller that is configured in advance on an AP |
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Term
| Protected access credential (PAC) |
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Definition
| Special-purpose data that is used as an authentication credential in EAP-FAST |
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Term
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Definition
| 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 through either MS-CHAPv2 or GTC. |
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Term
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Definition
| 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 DSSS format. |
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Term
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Definition
| A virtual MAC address that a controller assigns to each uniquely identified non-802.11 interferer so that it can be reported and displayed. See also cluster ID. |
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Term
| Public Key Infrastructure (PKI) |
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Definition
| An enterprise-wide system that generates and revokes digital certificates for client authentication |
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Term
| Quadrature amplitude modulation (QAM) |
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Definition
| A modulation method that combines QPSK phase shifting with multiple amplitude levels to produce a greater number of unique changes to the carrier signal. |
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Term
| What does the number infront of the QAM do |
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Definition
| Designates how many carrier signal changes are possible |
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Term
|
Definition
| A plot that shows the relative signal strength in dBm at every angle around an antenna |
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Term
|
Definition
| The portion of the frequency spectrum between 3 kHz and 300 GHz |
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Term
|
Definition
| An authentication server used with 802.1x to authenticate wireless clients |
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Term
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Definition
| The process by which a wireless client changes its association from one BSS to another as it moves |
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Term
| Received signal strength indicator (RSSI) |
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Definition
| The measure of signal strength (in dBm) as seen by the receiver. RSSI is normally negative (0 to ?100) because the received signal is always a degraded form of the original signal that was sent. |
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Term
|
Definition
| The effect of an RF signal meeting a dense, reflective material, such that it is sent in a different direction |
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Term
|
Definition
| The effect of an RF signal meeting the boundary between two different materials, causing its trajectory to change slightly |
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Term
|
Definition
| A device that repeats or retransmits signals it receives, effectively expanding the wireless coverage area |
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Term
|
Definition
| A wireless AP that operates outside local administrative control |
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Term
|
Definition
| A controller that is elected to handle all of the RRM algorithms for the entire RF group |
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Term
|
Definition
| A logical grouping of wireless LAN controllers that operates as a single RF domain. RRM algorithms run on a per-RF group basis. |
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Term
|
Definition
| A controller that is elected to handle all of the RRM algorithms for the entire RF group |
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Term
|
Definition
| The process a wireless client uses to move from one AP to another as it changes location |
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Term
|
Definition
| The RSSI threshold (in dBm) that divides unintelligible RF signals from useful ones |
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Term
|
Definition
| A physical nontrunking interface that connects a wireless controller to a switched network and carries only out-of-band management traffic |
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Term
| Service set identifier (SSID) |
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Definition
| A method used to authenticate a wireless device with a BSS by using a shared WEP key |
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Term
|
Definition
| Radio Resource Management; a set of algorithms that are used to maintain a stable and optimum wireless network even in a changing RF environment |
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Term
| Shared key authentication |
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Definition
| A method used to authenticate a wireless device with a BSS by using a shared WEP key |
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Term
| Signal-to-noise ratio (SNR) |
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Definition
| A measure of received signal quality, calculated as the difference between the signals?s RSSI and the noise floor. A higher SNR is preferred. |
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Term
|
Definition
| Distributing streams of data across multiple radio chains with spatial diversity |
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Term
|
Definition
| An 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 it travels through space. |
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Term
|
Definition
| A device that sweeps through a range of frequencies and displays signals that it receives. The signal data can be processed and displayed in a variety of ways to assist in the analysis. |
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Term
|
Definition
| RF signals that spread the information being sent over a wide range of frequencies |
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Term
|
Definition
| An 802.11 client device that is associated with a BSS |
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Term
|
Definition
| An 802.1x entity that exists as software on a client device and serves to request network access |
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Term
|
Definition
| An 802.11 data rate that can be supported by a client when it associates with an AP |
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Term
|
Definition
| A complete group of encoded chips that represent a data bit |
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Term
|
Definition
| Temporal Key Integrity Protocol |
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Term
|
Definition
| A wireless security scheme developed before 802.11i that provides a MIC for data integrity |
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Term
|
Definition
| Transmit power control; an RRM algorithm that adjusts the transmit power level of Aps to minimize cell overlap and interference |
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Term
| Traffic indication map (TIM) |
|
Definition
| 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. |
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Term
| Transmit beamforming (TxBF) |
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Definition
| An 802.11n method to transmit 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 |
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Term
| Unscheduled automatic power save deliver (U-APSD) |
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Definition
| The method defined in 802.11e and 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 |
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Term
|
Definition
| The method by which a wireless device calculates that a channel is available, based on frame duration information that is used to set the NAV |
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Term
|
Definition
| A logical link used to support wireless clients with things like DHCP relay and web authentication |
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Term
|
Definition
| The physical distance that a wave travels over one complete cycle |
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Term
| Wi-Fi Protected Access (WPA) |
|
Definition
| 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 |
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