Aironet Desktop Utility ADU Cisco software used to manage a single a/b/g wireless card.Airport Extreme The MAC-OSX wireless client.. Announcement Traffic Indication Message ATIM Used in
Trang 1Aironet Desktop Utility (ADU) Cisco software used to manage a single a/b/g wireless card.
Airport Extreme The MAC-OSX wireless client
amplifier Added between the AP and the antenna to strengthen the signal
amplitude The volume of the signal
anchor The original controller
Announcement Traffic Indication Message (ATIM) Used in IEEE 802.11 ad hoc or independent BSS networks to announce the existence of buffered frames when a client is in sleep mode
AP priming After the AP is associated with at least one controller, the AP gets a list of other controllers it can associate with from the one that is already associated with
ARP Address Resolution Protocol Used to resolve a MAC address to an IP address
association request A request from a client to the AP for association
association response A response from an AP to a client during open association
asymmetric tunneling Traffic from the client is routed to the destination, regardless of its source address The return traffic is sent to its original controller, called an anchor, and is tun-neled to the new controller
attenuator Reduces the signal if there is too much signal, causing bleed-over into other networks
authentication request A request from a client to an AP during open authentication
authentication response A response from an AP to a client during open authentication
authentication server An AAA server that has a list of users in one form or another that can verify the supplicant
authenticator The switch
Autonomous Workgroup Bridge (aWGB) A wireless bridge operating autonomously
autoprovisioning Simplifies deployments when you have a large number of controllers
azimuth The angle measured in degrees between a reference plane and a point
B backoff timer A random number that begins a countdown process while listening
bandwidth The frequency spectrum, measured in Hertz Bandwidth can refer to data rates
or the width of an RF channel
barker code Defines the use of 11 chips when encoding data
Basic Service Area (BSA) The coverage area of the AP
Basic Service Set (BSS) One device sets a network name and radio parameters, and the other uses it to connect
Trang 2Basic Service Set Identifier (BSSID) Only one network that an AP is offering service for.
beacon An announcement of services from an AP
Binary Phase Shift Keying (BPSK) A modulation technique used in 802.11 networks
block acknowledgment The confirmation from the recipient station, stating which frames have been received Used in 802.11n networks
Bluetooth A personal-area technology
bridge mode A mode that an AP can operate in, in which it bridges traffic from source to destination
C Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) When a device wants to send, it must listen first Similar to CSMA/CD
channel A defined frequency range
Channel State Information (CSI) If the receiver is moving, the reflection characteristics change, and the beamforming can no longer be coordinated
chipping code A code used to represent bits
circular polarization Indicates that the wave circles as it moves forward
Cisco Client Extension Program (CCX) A no-cost licensing of technology for use in WLAN adapters and devices
Cisco Configuration Assistant (CCA) A software application used to set up mobility express networks
Cisco Discovery Protocol (CDP) A Cisco-proprietary protocol that can gain information about directly connected Cisco devices
Cisco Site Survey Utility (CSSU) The optional software set that you select with a check-box during installation
Cisco Smart Business Communication System (SBCS) The Cisco solution for voice, video, and wireless for the small business
Cisco Wireless Location Appliance Maps clients and helps enforce security policies
Cisco Wizard Configuration Tool A wizard-type menu used to perform basic configura-tion
Clear Channel Assessment (CCA) A function found within physical layers that deter-mines the current state of use of a wireless medium
Clear-To-Send (CTS) A message indicating that it is clear to send data on the wireless medium
Clear-To-Send to self (CTS to self) A method indicating that it is clear to send data on a wireless network
Trang 3client MFP If the client is running CCX 5 or better, it can actually talk to the AP and find out what the MIC is
co-channel interference Crosstalk between channels that are next to each other
Code Division Multiple Access (CDMA) A channel access method
community A group name for your mobility express network
Complementary Code Keying (CCK) Uses a series of codes called complementary sequences
contention window The total amount of time that Station A waits before sending
control frame Used to acknowledge when data frames are received
CSSC Cisco Secure Services Client software
D data frame A frame that contains data
deauthentication message When a client is connected to a wireless cell, either the client
or the AP can leave the connection by sending this message This message has information in the body about why it is leaving
deauthentication response A response to a deauthentication message
destination address (DA) A frame’s final destination
Digital Enhanced Cordless Telecommunications (DECT) An ETSI standard for digital portable phones Found in cordless technology that is deployed in homes or business
dipole See rubber duck
directional antenna Mounted on a wall Its radiation pattern is focused in a certain direction
Direct Sequence Spread Spectrum (DSSS) The modulation technique used by 802.11b devices to send data The transmitted signal is spread across the entire frequency spectrum that is being used
disassociation message Disassociates from the cell but keeps the client authenticated
disassociation response A response to a disassociation message
Distributed Coordination Function (DCF) Each station is responsible for coordinating the sending of its data
Distributed Interframe Space (DIFS) Each sending station must wait after a frame is sent before sending the next frame
distribution system The AP connects to a distribution system to get to server farms, the Internet, and other subnets
diversity vertical polarization The use of two antennas for each radio to increase the odds of receiving a better signal on either of the antennas
dual-patch “omnidirectional” Two patch directional antennas are placed back to back, making it “omnidirectional.”
Trang 4Dynamic Frequency Control (DFC) The ability to change frequency to avoid radar sig-nals
dynamic interface Includes the user-defined list
Dynamic Rate Shifting (DRS) The capability of a wireless network to shift to a lower rate
as a client moves farther away from the AP
E Effective Isotropic Radiated Power (EIRP) Used to estimate the service area of a device
The formula is as follows:
EIRP = transmitter – cable loss + antenna gain
elevation plane (E-plane) The vertical pattern does not propagate evenly
Enhanced Data Rate (EDR) A Bluetooth 2.0 feature providing up to three times the band-width for Bluetooth clients
exposed node issue When there are two wireless cells on the same channel and they are too close to each other
Extended Rate Physical (ERP) Devices that have extended data rates
Extended Service Area (ESA) More than one AP is connected to a common distribution system
Extensible Authentication Protocol (EAP) Controls the authentication process under the premise that no matter what EAP method you use, the basic steps will reamain the same
Extensible Authentication Protocol-Flexible Authentication via Secure Tunnel (EAP-FAST) Created to address weaknesses in Lightweight Extensible Authentication Protocol (LEAP) Uses PAC, not PKI
Extensible Authentication Protocol-Transport Layer Security (EAP-TLS) A
common-ly used EAP method for wireless networks
European Telecommunications Standards Institute (ETSI) Produces globally applica-ble standards for Information and Communications Technologies (ICT), including fixed, mobile, radio, converged, broadcast, and Internet technologies
F Federal Communications Commission (FCC) An independent U.S government agency established by the Communications Act of 1934 It regulates interstate and international com-munications by radio, television, wire, satellite, and cable The FCC’s jurisdiction covers the
50 states, the District of Columbia, and U.S possessions
Frame Check Sequence (FCS) Extra checksum characters added to a frame in a commu-nication protocol for error detection and correction
free path loss The loss in signal strength of an electromagnetic wave that results from a line-of-sight path through free space, where no obstacles are nearby to cause reflection or diffraction
Trang 5frequency The pitch of the signal.
Frequency Division Multiple Access (FDMA) An access technology that radio systems use to share the radio spectrum, commonly found in 802.11 networks
Frequency Hopping Spread Spectrum (FHSS) A spread spectrum method in which the signal hops between channels If a channel experiences interference, it can be skipped
G Generic Token Card (GTC) Authenticates the user inside an encrypted tunnel
Global System for Mobile Communication (GSM) A digital mobile telephony system that uses a variation of time-division multiple access (TDMA) The most widely used of the three digital wireless telephony technologies (TDMA, GSM, and CDMA) GSM operates at either the 900-MHz or 1800-MHz frequency band
Group Master Key (GMK) Used by the AP to generate a group random number
Group Temporal Key (GTK) Generated by the GMK random number Provides a group key and a MIC This key changes when it times out or when a client leaves the network
Group Transient Key (GTK) Used to decrypt broadcast and multicast
H Hertz (Hz) Used to measure bandwidth Hertz measures the number of cycles per second One Hertz is one cycle per second
hidden node issue When more than one client tries to send on the same channel at the same time They are in range of the AP but not each other
hidden node problem When two devices cannot hear each other
horizontal plane (H-plane) The horizontal plane of an omnidirectional polarized antenna, opposite the E-plane
horizontal polarization The wave goes left and right in a linear way
hybrid REAP mode Hybrid Remote Edge Access Point (H-REAP) is a solution for branch office and remote office deployments It lets you configure access points (AP) in a branch or remote office from the corporate office through a wide-area network (WAN) link without the need to deploy a controller in each office
I Independent Basic Service Set (IBSS) When two machines do not need a central device
to speak to each other
Industry, Scientific, and Medical (ISM) frequency bands Use of spread spectrum in the commercial market
Trang 6infrastructure Refers to assets that support a network.
infrastructure device The access point (AP)
infrastructure MFP Management Frame Protection performed by APs
initialization vector (IV) A block of bits that is used to produce a unique encryption key
Institute for Electrical and Electronics Engineers (IEEE) A nonprofit organization, IEEE is the world’s leading professional association for the advancement of technology
intercontroller roaming When a user roams from one controller to another but remains on the same VLAN
interface The logical, dynamic, or static port of a network device Also refers to VLANs
interframe spacing (IFS) A period of time that a station has to wait before it can send
intracontroller roaming When roaming is handled within a single controller
IP Setup utility Takes the MAC address of the AP and resolves the IP address associated with it
isotropic radiator A reference that assumes that the signal is propagated evenly in all direc-tions This would be a perfect 360-degree sphere in all directions, on the H- and E-planes
iwconfig The command-line tool for Linux to work with WLANs
J–K join request message A message sent by an AP to join a wireless controller
L Layer 3 LWAPP mode The default LWAPP mode on most Cisco devices
lightning arrestor Prevents surges from reaching the RF equipment by the device’s shunt-ing effect
Lightweight Access Point Protocol (LWAPP) A protocol used for communication between a lightweight AP and a wireless controller
lightweight AP An AP that receives configuration from a controller and cannot function without the controller
Lightweight Extensible Authentication Protocol (LEAP) Uses a proprietary algorithm
to create the initial session key
Line-of-Sight (LOS) The signal between the two points that appears to be a straight shot
link budget A value that accounts for all the gains and losses between sender and receiver
It accounts for attenuation, antenna gain, and other miscellaneous losses that may occur
local mode The standard operating mode of an access point
LWAPP discovery request An LWAPP message used to discover a controller
LWAPP discovery response A response from a controller to an AP during discovery
Trang 7M management frame Used to join and leave a wireless cell
Management Frame Protection (MFP) A method used to detect spoofed management frames in which valid frames contain a hash that spoofed frames would not
master controller Configured in the GUI interface by choosing CONTROLLER >
Advanced > Master Controller Mode
Maximum Transmission Unit (MTU) The largest frame size supported on an interface
Message Integrity Check (MIC) A cryptographic hash in each management frame used
to ensure that data is not tampered with
Microsoft Challenge Handshake Authentication Protocol version 2 (MS-CHAPv2) A protocol used to authenticate the user inside an encrypted tunnel in Microsoft Windows Active Directory
mobility anchor A feature in which all the client traffic that belongs to a WLAN
(especial-ly the guest WLAN) is tunneled to a predefined WLC or a set of controllers that are config-ured as an anchor for that specific WLAN Also called guest tunneling or auto-anchor mobility
mobility domain A controller can be aware of another controller in a different mobility group
mobility group A setting that defines the controller as a member of a group
monitor mode A mode that an AP can operate in where it constantly scans all channels to perform rouge detection When in this mode, the AP cannot service clients
multipath Defines when portions of signals are reflected and then arrive out of order at the receiver
Multiple Basic Service Set Identifier (MBSSID) Used when the AP has more than one network
Multiple-Input Multiple-Output (MIMO) A technology that is used in the new 802.11n specification A device that uses MIMO technology uses multiple antennas to receive signals, usually two or three, as well as multiple antennas to send signals
N N+1 A method of controller redundancy—a controller plus one for backup
N+N Two active controllers that can back each other up
N+N+1 Two controllers backing each other up, with a dedicated backup as a last resort
native VLAN The VLAN on a trunk that does not get tagged
NAV Norton AntiVirus
N connector A type of antenna connector
network manager A graphical user interface (GUI) tool that enables the creation of wire-less profiles in Linux
Trang 8node Another term for an access point in a mesh network.
null function frame The client wakes up after a certain period of time, during which the
AP buffers any traffic for it
NVRAM Nonvolatile RAM A storage location used to keep configuration files
O omnidirectional antenna An antenna type that does not focus a signal in one direction
one-floor concept The signal propagates wider from side to side than from top to bottom
Therefore, the signal can offer coverage to the floor it is placed on rather than to the floor above or below the AP
Orthogonal Frequency Division Multiplexing (OFDM) Defines a number of channels in
a frequency range Not considered a spread spectrum technology but is used for modulation
in a wireless network
Over-the-Air Provisioning (OTAP) A method for APs to discover the management IP of a controller over the air
P Pairwise Master Key (PMK) A wireless security key
Pairwise Transient Key (PTK) This type of key confirms the PMK between two devices, establishes a temporal key to be used for message encryption, authenticates the negotiated parameters, and creates keying material for the next phase, called the two-way group key handshake
parabolic dish Has a very narrow path and is very focused in its radiation pattern
passive scan A scan in which wireless clients mark the channels on which a beacon is heard
phase The timing of the signal between peaks
Point Coordination Function (PCF) The AP is responsible for coordinating the sending of its data
polarity The direction in which the RF is sent from an antenna—horizontal or vertical
port A physical interface on your controller
precoding A function that takes advantage of multiple antennas and the multipath issue
probe request A client request for an AP
probe response A response to a probe request
protected EAP (PEAP) Only a server-side certificate is used to create a tunnel, and then the real authentication takes place inside
PS-poll Power-save poll
Trang 9Q–R Quadrature Phase Shift Keying (QPSK) A version of frequency modulation in which the phase of the carrier wave is modulated to encode bits of digital information in each phase change
radiation pattern The direction of the RF propagation
Radio Resource Management (RRM) A software feature of the Cisco controller that acts
as a built-in RF engineer to consistently provide real-time RF management of your wireless network
RAM Random-access memory, used during operation Lost when the system reloads
Real-Time Operating System (RTOS) The controller’s operating system
Receiving Address (RA) The address of the direct station that this frame is sent to
Reduced Interframe Space (RIFS) A smaller interframe space, reducing delay and over-head
reflection Happens when a signal bounces off something and travels in a different direc-tion
refraction The change in direction or the bending of a waveform as it passes through some-thing that has a different density
repeater A device that repeats a signal to extend distance
Request-To-Send (RTS) A request to send on a wireless network
response In a wireless LAN, a response to a request for connectivity
Reverse-Polarity Threaded Neill-Concelman (RP-TNC) A type of antenna connector
roaming A client moving from one AP to another AP, overlapping
rogue detector mode A mode an AP can operate in to look for rogue devices When operating in this mode, an AP looks on the wireless network for ARP messages from rogue devices
rubber duck A common wireless antenna in a rubber sheath
S scattering The signal is sent in many different directions This can be caused by an object that has reflective yet jagged edges, or dust particles in the air and water
Secure Services Client Administration Utilities (SSCAU) A component of Cisco Secure Services Client (SSC) client software that enables the administrator to create complex profiles
Service Set Identifier (SSID) The name of a wireless network
Short Interframe Space (SIFS) For higher priority Used for ACKs, among other things
Signal-to-Noise Ratio (SNR) How much stronger the signal is compared to the surround-ing noise that corrupts it
Trang 10site survey A measurement of a certain point in time—the time when you did the site survey
slottime The speed at which the backoff timer countdown occurs
Small to Mid-Size Business (SMB) A business that has customers seeking to gain a com-petitive edge without having to compromise between price and sophistication
sniffer mode A mode that an AP can operate in to capture data and forward 802.11 pack-ets to an application such as Wireshark for analysis
sniff subrating Increases battery life up to five times
source address (SA) The stations that sent the frame
spatial multiplexing Takes a signal, splits it into a bunch of lower-rate streams, and then sends each one out different antennas
Special Interest Group (SIG) A Bluetooth group
splitter Used in outdoor wireless deployments to split in two a signal coming from a cable, and send it in two directions
static interface Includes management interface, AP-Manager, service port
station (STA) The client on a network
supplicant A device that can use an EAP method to prove its identity to the authentication server
symmetric tunneling All traffic is tunneled from the client to the anchor controller, sent to the destination, returned to the anchor controller, and then tunneled back to the client via the foreign controller
T Temporal Key Integrity Protocol (TKIP) A method of automatically changing the keys
TFTP Trivial File Transfer Protocol Used to copy files between a client and server using UDP port 69
Time Division Multiple Access (TDMA) An access method that allocates time slots to access the network
Traffic Indication Map (TIM) This field indicates whether the AP is buffering traffic for clients in power-save mode
Transmit Beamforming (TxBF) A technique that is used when there is more than one transmit antenna The signal is coordinated and sent from each antenna so that the signal at the receiver is dramatically improved, even if it is far from the sender
Transmit Power Control (TPC) The ability to adjust power dynamically, and a require-ment for use in the UNII bands
Transmitter Address (TA) The address of the station that is emitting the frame
trunk port A port that carries traffic for multiple VLANs by tagging traffic from each VLAN