Wireless & Mobility terms

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• 1024-QAMModulation with 1,024 constellation points carrying 10 bits per symbol, introduced in 802.11ax.Intermediate
• 2.4 GHz BandThe 2.400-2.4835 GHz ISM band used by 802.11b/g/n/ax, with only three non-overlapping 20 MHz channels in North America.Foundational
• 256-QAMModulation with 256 constellation points carrying 8 bits per symbol, introduced to Wi-Fi by 802.11ac.Intermediate
• 320 MHz ChannelThe widest Wi-Fi channel, introduced by Wi-Fi 7 and available only in 6 GHz.Intermediate
• 4096-QAMModulation with 4,096 constellation points carrying 12 bits per symbol, introduced in 802.11be (Wi-Fi 7).Intermediate
• 5 GHz BandWi-Fi spectrum from about 5.150 to 5.895 GHz divided into U-NII sub-bands, offering many non-overlapping channels.Foundational
• 5G Core (5GC)The cloud-native, service-based 5G core network with functions such as AMF, SMF, and UPF.Intermediate
• 5G New Radio (5G NR)The 3GPP 5G air interface (Release 15 onward) operating in FR1 (sub-7 GHz) and FR2 (mmWave) bands.Foundational
• 6 GHz BandThe 5.925-7.125 GHz band (up to 1,200 MHz) opened to Wi-Fi 6E and Wi-Fi 7 in the US in 2020.Foundational
• 60 GHz BandUnlicensed millimeter-wave spectrum around 57-71 GHz used for WiGig and short links.Advanced
• AbsorptionConversion of RF energy into heat as a signal passes through a material.Foundational
• Access CategoryOne of four WMM traffic queues: voice (AC_VO), video (AC_VI), best effort (AC_BE), and background (AC_BK).Intermediate
• Acknowledgment FrameA control frame confirming successful receipt of a unicast frame.Intermediate
• Action FrameA management frame subtype used to request or perform specific actions such as block ACK setup or neighbor reports.Advanced
• Active ScanningDiscovering APs by transmitting probe requests on channels and listening for responses.Intermediate
• Adjacent Channel Interference (ACI)Corruption caused by transmitters on overlapping or nearby channels.Intermediate
• Aggregate MAC Protocol Data Unit (A-MPDU)Multiple MPDUs, each with its own MAC header and FCS, combined into one PPDU.Advanced
• Aggregate MAC Service Data Unit (A-MSDU)Multiple MSDUs combined under one MAC header and FCS.Advanced
• AI-Enhanced RRMCisco RRM computed in the cloud with historical data via Catalyst Center to optimize RF over time.Advanced
• AirMatchHPE Aruba Networking's centralized RF optimization that computes channel, width, and power plans.Advanced
• AirtimeThe amount of time on the shared medium consumed by a transmission or client.Intermediate
• Airtime Fairness (ATF)A feature that allocates airtime more evenly among clients or SSIDs rather than per frame.Intermediate
• AmplitudeThe height or strength of an RF wave, corresponding to signal power.Foundational
• Amplitude Shift Keying (ASK)Modulation that represents data by changing the carrier's amplitude.Intermediate
• Angle of Arrival (AoA)A location method that determines signal direction from phase differences across an antenna array.Advanced
• AntennaA device that converts electrical RF signals into radiated electromagnetic waves and back again.Foundational
• Antenna AlignmentAiming directional antennas precisely at each other to maximize received signal on a link.Intermediate
• Antenna ArrayMultiple antenna elements arranged to create a controllable combined radiation pattern.Advanced
• Antenna DiversityUsing multiple antennas to improve reception by selecting or combining the best signal.Intermediate
• Antenna GainThe increase in signal strength in a given direction achieved by focusing radiated energy.Foundational
• AP Join ProfileA Catalyst 9800 profile defining AP management settings such as CAPWAP timers, credentials, and SSH.Advanced
• Application Visibility and Control (AVC)Cisco deep packet inspection feature that identifies applications and applies QoS or drop policies.Advanced
• Arbitration Interframe Space (AIFS)The EDCA wait time per access category, calculated as SIFS plus AIFSN slot times.Advanced
• Association Identifier (AID)A number assigned by an AP to each associated station, used in the TIM bitmap.Advanced
• Association RequestA management frame from a client asking to join a BSS, listing its capabilities and chosen security.Foundational
• Association ResponseA management frame from the AP accepting or rejecting an association request.Intermediate
• Authentication and Key Management Suite (AKM)The RSN element field identifying how a BSS authenticates and derives keys, such as 802.1X, PSK, SAE, or FT.Advanced
• Authentication FrameA management frame used for 802.11 authentication before association; also carries SAE exchanges.Intermediate
• Automated Frequency Coordination (AFC)A cloud database system that authorizes 6 GHz standard-power operation while protecting incumbent links.Intermediate
• Autonomous Access PointA standalone AP that contains all configuration, management, and control functions locally.Foundational
• Azimuth ChartA polar chart showing an antenna's horizontal (top-down) radiation pattern.Intermediate
• Band SteeringEncouraging dual-band clients to connect on 5 GHz or 6 GHz instead of 2.4 GHz.Intermediate
• Barker CodeAn 11-chip spreading code used for 1 and 2 Mbps DSSS data rates.Advanced
• Basic RateA data rate that all clients must support to join a BSS; management frames use the lowest one.Intermediate
• Basic Service Set (BSS)An AP and its associated client stations, the basic building block of an 802.11 WLAN.Foundational
• Basic Service Set Identifier (BSSID)The 48-bit MAC address that uniquely identifies a BSS, usually the AP radio's MAC per SSID.Intermediate
• Beacon FrameA management frame broadcast periodically by an AP to advertise its BSS and capabilities.Foundational
• BeamwidthThe angle between the half-power (-3 dB) points of an antenna's main lobe.Intermediate
• Binary Phase Shift Keying (BPSK)PSK using two phase states to carry 1 bit per symbol.Intermediate
• Block Acknowledgment (BA)A single control frame acknowledging multiple frames, introduced by 802.11e and required for A-MPDU.Advanced
• BluetoothA short-range 2.4 GHz wireless personal area network technology standardized by the Bluetooth SIG.Foundational
• Bluetooth Low Energy (BLE)A low-power Bluetooth variant using 40 2-MHz channels, widely used for IoT sensors and location beacons.Intermediate
• BonjourApple's zero-configuration service discovery using mDNS and DNS-SD on UDP 5353.Intermediate
• BSS ColoringAn 802.11ax identifier (1-63) in the PHY header that distinguishes overlapping BSSs on the same channel.Intermediate
• BSS Transition Management (BTM)An 802.11v exchange in which the AP suggests that a client roam to listed candidate APs.Intermediate
• Captive PortalA web page that intercepts a user's HTTP traffic and requires acceptance or login before granting access.Foundational
• Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)The 802.11 medium access method in which stations sense the medium and back off randomly before transmitting.Foundational
• Central SwitchingForwarding client data through a CAPWAP tunnel to the controller, which bridges it to the wired network.Intermediate
• Central Web Authentication (CWA)A guest flow where the RADIUS server redirects clients to its own portal and then uses CoA to grant access.Advanced
• Change of Authorization (CoA)RADIUS extension (RFC 5176) allowing the server to change or terminate an active session.Advanced
• Channel BondingCombining adjacent 20 MHz channels into 40, 80, 160, or 320 MHz channels for higher data rates.Intermediate
• Channel Reuse PlanAn assignment of channels to APs so neighbors use different channels and same-channel APs are separated.Intermediate
• Channel SoundingThe exchange used to measure the RF channel to compute beamforming steering matrices.Advanced
• Channel State Information (CSI)Detailed per-subcarrier amplitude and phase data describing how a channel affects a signal.Advanced
• Channel UtilizationThe percentage of time a channel is busy, measured by an AP's radio.Intermediate
• Channel WidthThe amount of spectrum a Wi-Fi channel occupies: 20, 40, 80, 160, or 320 MHz.Foundational
• Cisco Catalyst 9800 Series Wireless Controller (C9800)Cisco's IOS XE-based wireless controller family, available as appliances, VM (9800-CL), and embedded options.Intermediate
• Cisco CleanAirCisco AP hardware-based spectrum analysis that identifies and classifies RF interference sources.Intermediate
• Cisco SpacesCisco's cloud indoor location and IoT services platform, formerly Cisco DNA Spaces.Advanced
• Citizens Broadband Radio Service (CBRS)US shared spectrum at 3550-3700 MHz managed by Spectrum Access Systems in three tiers.Intermediate
• ClauseA numbered section of the 802.11 standard; PHYs are often referenced by clause number.Advanced
• Clear Channel Assessment (CCA)The physical carrier-sense function that determines whether the medium is busy.Advanced
• Clear to Send-to-Self (CTS-to-Self)A CTS frame addressed to the sender itself, used to set NAV with less overhead than RTS/CTS.Advanced
• Client SteeringInfrastructure techniques that encourage clients to roam to a better AP or band.Intermediate
• ClientMatchHPE Aruba Networking feature that steers clients to the optimal AP and band using 802.11v and other methods.Advanced
• Cloud-Managed WirelessA WLAN architecture in which APs are configured and monitored through a cloud service rather than an on-premises controller.Foundational
• Co-Channel Interference (CCI)Performance loss when nearby BSSs on the same channel must defer to each other's transmissions.Intermediate
• Coding RateThe ratio of data bits to total transmitted bits after error-correction coding.Intermediate
• Complementary Code Keying (CCK)The 8-chip coding used by 802.11b HR-DSSS to reach 5.5 and 11 Mbps.Advanced
• Contention Window (CW)The range from which a station randomly selects its backoff value; it grows after failed transmissions.Advanced
• Control and Provisioning of Wireless Access Points (CAPWAP)IETF tunneling protocol (RFC 5415) between lightweight APs and controllers, using UDP 5246 and 5247.Foundational
• Control FrameAn 802.11 frame type (type 1) that assists delivery of data and management frames.Intermediate
• Controller DiscoveryThe process by which a lightweight AP locates and joins a WLC.Intermediate
• Counter Mode with CBC-MAC Protocol (CCMP)The AES-based 802.11i encryption protocol using CTR mode for confidentiality and CBC-MAC for integrity.Intermediate
• Coverage Hole Detection (CHD)Cisco RRM feature that raises AP power when clients report poor signal.Advanced
• Data FrameAn 802.11 frame type (type 2) that carries upper-layer payloads or signals power state.Intermediate
• Data RateThe PHY signaling speed at which bits are transmitted over the air, not user throughput.Foundational
• Deauthentication FrameA management notification frame that ends authentication and association.Intermediate
• Decibel Relative to Dipole (dBd)Antenna gain in decibels compared with a half-wave dipole antenna.Intermediate
• Decibel Relative to Isotropic Radiator (dBi)Antenna gain in decibels compared with a theoretical isotropic radiator.Foundational
• Decibel-Milliwatt (dBm)Absolute power level in decibels relative to 1 milliwatt (0 dBm = 1 mW).Foundational
• Delay SpreadThe time difference between the first and last significant multipath arrivals of a signal.Advanced
• Delivery Traffic Indication Message (DTIM)A special TIM indicating that buffered broadcast and multicast frames will be sent after the beacon.Advanced
• DHCP Option 43A vendor-specific DHCP option used to give APs the IP address of their wireless controller.Intermediate
• Differentiated Services Code Point MappingTranslating Layer 3 DSCP markings to 802.11 user priorities and back, for end-to-end wireless QoS.Advanced
• DiffractionBending of an RF wave around the edge of an obstacle, creating an RF shadow behind it.Intermediate
• Dipole AntennaThe simplest common omnidirectional antenna, typically 2.14 dBi gain.Foundational
• Direct-Sequence Spread Spectrum (DSSS)Spreading each bit across a wide channel using a chipping code, used by 802.11 and 802.11b.Intermediate
• Disassociation FrameA management notification frame that ends an association but not authentication.Intermediate
• Distributed Coordination Function (DCF)The mandatory 802.11 contention-based access method implementing CSMA/CA without QoS.Advanced
• Distributed Interframe Space (DIFS)The interframe space non-QoS stations wait before contending: SIFS plus two slot times.Advanced
• Distribution System (DS)The system that interconnects APs and integrates the WLAN with other networks.Intermediate
• Distribution System Medium (DSM)The physical medium connecting APs in a distribution system, usually 802.3 Ethernet.Advanced
• DowntiltAngling an antenna's beam downward to aim coverage at the ground area that needs it.Advanced
• Dual-Band Access PointAn AP with radios operating simultaneously in two bands, typically 2.4 GHz and 5 GHz.Foundational
• Duration FieldThe MAC header field indicating how long, in microseconds, the medium will remain reserved.Advanced
• Duty CycleThe percentage of time an RF transmitter is active on a frequency.Intermediate
• Dynamic Bandwidth Selection (DBS)Cisco RRM feature that automatically selects channel width per AP.Advanced
• Dynamic Channel Assignment (DCA)Cisco RRM algorithm that automatically assigns AP channels to minimize interference.Advanced
• Dynamic Frequency Selection (DFS)A requirement that 5 GHz devices detect radar and vacate the channel when radar is present.Intermediate
• Dynamic Rate Switching (DRS)Automatic adjustment of a client's data rate as signal quality changes; also called rate shifting.Intermediate
• Dynamic VLAN AssignmentAssigning a client VLAN based on RADIUS attributes returned after authentication.Intermediate
• Earth BulgeThe curvature of the earth that must be cleared on outdoor links longer than about 7 miles (11 km).Advanced
• Effective Isotropic Radiated Power (EIRP)The highest signal strength radiated from an antenna: transmitter power minus cable loss plus antenna gain.Foundational
• Electromagnetic WaveA self-propagating wave of oscillating electric and magnetic fields traveling at the speed of light.Foundational
• Elevation ChartA polar chart showing an antenna's vertical (side view) radiation pattern.Intermediate
• Embedded Wireless Controller (EWC)Catalyst 9800 controller software running on a Catalyst access point or switch for small deployments.Advanced
• Energy Detect (ED)The CCA method that marks the medium busy when any RF energy exceeds a threshold, even if undecodable.Advanced
• Enhanced Distributed Channel Access (EDCA)The 802.11e contention-based QoS access method using four access categories with different timers.Advanced
• Error Vector Magnitude (EVM)A measure of how far received symbols deviate from their ideal constellation points.Advanced
• European Telecommunications Standards Institute (ETSI)The European standards body whose standards define radio equipment rules for Wi-Fi in Europe.Intermediate
• Exposed NodeA station that unnecessarily defers because it hears a transmission that would not actually collide.Advanced
• Extended Rate PHY (ERP)The 802.11g PHY that combines OFDM and DSSS/CCK in 2.4 GHz.Advanced
• Extended Service Set (ESS)Multiple BSSs sharing the same SSID and connected by a distribution system, allowing roaming.Foundational
• Extensible Authentication Protocol Tunneled Transport Layer Security (EAP-TTLS)A tunneled EAP method using a server certificate that supports legacy inner methods such as PAP and CHAP.Intermediate
• Extensible Authentication Protocol-Authentication and Key Agreement (EAP-AKA)EAP methods (EAP-SIM, EAP-AKA, EAP-AKA') that authenticate Wi-Fi users with mobile network SIM credentials.Advanced
• Extensible Authentication Protocol-Flexible Authentication via Secure Tunneling (EAP-FAST)A Cisco-developed tunneled EAP method (RFC 4851) that can use a Protected Access Credential instead of certificates.Advanced
• Extremely High Throughput (EHT)The 802.11be PHY and MAC enhancements.Intermediate
• Fade MarginExtra signal strength above receiver sensitivity planned into a link to absorb fluctuations.Intermediate
• Fast BSS Transition (FT)802.11r method that pre-derives keys from a key hierarchy so clients can roam without a full 802.1X or 4-way exchange.Intermediate
• Federal Communications Commission (FCC)The US regulator that governs RF spectrum use, including unlicensed Wi-Fi bands.Foundational
• Fine Timing Measurement (FTM)An 802.11 round-trip-time ranging method that measures distance between a station and AP using timestamps.Advanced
• FlexConnectCisco AP mode for branch sites that can switch client traffic locally and survive WAN outages.Intermediate
• Flexible Radio Assignment (FRA)Cisco RRM feature that converts redundant 2.4 GHz radios on flexible APs into 5 GHz or monitor radios.Advanced
• Forward Error Correction (FEC)Adding redundant bits so a receiver can correct errors without retransmission.Intermediate
• Forward SecrecyA property ensuring that compromise of a long-term secret does not expose past session keys.Intermediate
• Four-Address FrameAn 802.11 frame with To DS and From DS both set, carrying transmitter, receiver, source, and destination addresses.Advanced
• Four-Way HandshakeThe EAPOL-Key exchange that confirms the PMK and derives the PTK and delivers the GTK.Intermediate
• Frame AggregationCombining multiple frames into a single transmission to reduce overhead.Intermediate
• Free Space Path Loss (FSPL)Natural decrease in signal amplitude as an RF wave spreads out over distance.Foundational
• FrequencyThe number of times a wave completes a cycle per second, measured in hertz (Hz).Foundational
• Frequency Division Duplex (FDD)Using separate paired frequencies for uplink and downlink simultaneously.Intermediate
• Frequency Shift Keying (FSK)Modulation that represents data by shifting the carrier frequency.Intermediate
• Frequency-Hopping Spread Spectrum (FHSS)Transmitting on one narrow frequency at a time while hopping in a pseudorandom sequence.Intermediate
• Fresnel ZoneThe football-shaped area around the visual line of sight between two antennas that must be kept clear.Intermediate
• Front-to-Back RatioThe ratio of an antenna's gain in its forward direction to its gain in the opposite direction.Advanced
• Galois/Counter Mode Protocol (GCMP)An AES-based authenticated encryption protocol for Wi-Fi, used as GCMP-256 in WPA3-Enterprise 192-bit and Wi-Fi 7.Advanced
• Gaussian Frequency Shift Keying (GFSK)FSK with Gaussian filtering to smooth frequency transitions, used by Bluetooth.Advanced
• GroundingConnecting outdoor RF equipment and masts to earth ground for safety and surge protection.Intermediate
• Group Temporal Key (GTK)The shared key used to encrypt broadcast and multicast traffic within a BSS.Advanced
• Guard Interval (GI)A period between OFDM symbols that absorbs multipath echoes to prevent inter-symbol interference.Intermediate
• Guest Anchor ControllerA controller, typically in a DMZ, to which guest traffic is tunneled from foreign controllers.Advanced
• Guest NetworkA WLAN that provides visitors with internet-only access isolated from internal resources.Foundational
• Hertz (Hz)The SI unit of frequency equal to one cycle per second.Foundational
• Hidden NodeA station that cannot hear another station's transmissions, causing both to transmit and collide at the AP.Intermediate
• Hidden SSIDConfiguring an AP not to include its SSID in beacons, also called SSID cloaking.Foundational
• High Availability Stateful Switchover (HA SSO)Controller redundancy where a standby WLC maintains AP and client state for subsecond failover.Advanced
• High Efficiency (HE)The 802.11ax PHY and MAC enhancements.Intermediate
• High Throughput (HT)The PHY and MAC enhancements introduced by 802.11n.Intermediate
• Highly Directional AntennaAn antenna with very narrow beamwidth and high gain, used for long point-to-point links.Intermediate
• Hotspot 2.0 (HS2.0)Wi-Fi Alliance Passpoint technology enabling automatic, secure roaming onto public Wi-Fi using 802.11u and ANQP.Advanced
• HPE Aruba Networking CentralHPE's cloud (or on-premises) network management platform for Aruba APs, switches, and gateways.Intermediate
• Identity Pre-Shared Key (iPSK)A WLAN design in which each user or device group has its own passphrase on the same SSID.Intermediate
• IEEE 802.11The IEEE family of standards defining wireless LAN PHY and MAC layers, commonly known as Wi-Fi.Foundational
• IEEE 802.11a1999 amendment defining OFDM in the 5 GHz band with data rates up to 54 Mbps.Foundational
• IEEE 802.11ac2013 amendment (Wi-Fi 5) for 5 GHz only, adding 80/160 MHz channels, 256-QAM, up to 8 streams, and downlink MU-MIMO.Foundational
• IEEE 802.11adAmendment (WiGig) for multi-gigabit Wi-Fi in the 60 GHz band over very short range.Intermediate
• IEEE 802.11ahAmendment for sub-1 GHz Wi-Fi supporting long-range, low-power IoT; marketed as Wi-Fi HaLow.Intermediate
• IEEE 802.11axAmendment (Wi-Fi 6/6E) focused on efficiency in dense environments with OFDMA, UL/DL MU-MIMO, 1024-QAM, and TWT.Foundational
• IEEE 802.11ayEnhancement to 60 GHz Wi-Fi (EDMG) adding channel bonding and MIMO for tens of Gbps.Advanced
• IEEE 802.11azNext Generation Positioning amendment improving Wi-Fi ranging accuracy and security.Advanced
• IEEE 802.11b1999 amendment defining HR-DSSS in 2.4 GHz with data rates of 1, 2, 5.5, and 11 Mbps.Foundational
• IEEE 802.11bbAmendment defining light communications (Li-Fi) using the 802.11 MAC.Advanced
• IEEE 802.11beAmendment marketed as Wi-Fi 7, adding 320 MHz channels, 4096-QAM, Multi-Link Operation, and Multi-RU.Foundational
• IEEE 802.11bfAmendment defining WLAN sensing, using Wi-Fi signals to detect motion and presence.Advanced
• IEEE 802.11bnAmendment in development, expected to be Wi-Fi 8, focused on Ultra High Reliability (UHR).Advanced
• IEEE 802.11dAmendment allowing APs to advertise country regulatory information in beacons.Intermediate
• IEEE 802.11eAmendment adding quality of service to the 802.11 MAC, including EDCA and HCCA.Intermediate
• IEEE 802.11g2003 amendment bringing OFDM (ERP) to 2.4 GHz with rates up to 54 Mbps, backward compatible with 802.11b.Foundational
• IEEE 802.11hAmendment adding DFS and TPC so 5 GHz Wi-Fi can coexist with radar and meet European rules.Intermediate
• IEEE 802.11i2004 security amendment defining Robust Security Networks with CCMP/AES, TKIP, and 802.1X/PSK key management.Intermediate
• IEEE 802.11kRadio resource measurement amendment that lets clients request neighbor reports to roam faster.Intermediate
• IEEE 802.11mcRevision work that introduced Fine Timing Measurement (FTM) for Wi-Fi round-trip-time location.Advanced
• IEEE 802.11n2009 amendment (Wi-Fi 4) adding MIMO, 40 MHz channels, and frame aggregation in 2.4 and 5 GHz, up to 600 Mbps.Foundational
• IEEE 802.11rFast BSS Transition amendment that allows key negotiation during or before reassociation for fast roaming.Intermediate
• IEEE 802.11sAmendment defining standardized wireless mesh networking among 802.11 stations.Advanced
• IEEE 802.11uInterworking with External Networks amendment enabling pre-association network discovery.Intermediate
• IEEE 802.11vWireless network management amendment including BSS Transition Management and other client steering features.Intermediate
• IEEE 802.11wAmendment that protects selected management frames such as deauthentication and disassociation.Intermediate
• IEEE 802.15.4IEEE standard for low-rate wireless personal area network PHY and MAC layers used by Zigbee and Thread.Advanced
• ImpedanceThe opposition to alternating current flow, measured in ohms; Wi-Fi RF systems use 50 ohms.Intermediate
• IMSI CatcherA fake cellular base station that tricks phones into connecting to capture identities or intercept traffic.Advanced
• Independent Basic Service Set (IBSS)An ad hoc network of stations communicating directly without an AP.Intermediate
• Industrial, Scientific, and Medical Band (ISM)Unlicensed frequency bands, including 902-928 MHz and 2.400-2.4835 GHz, used by Wi-Fi and other devices.Foundational
• Infrastructure ModeWLAN operation in which clients connect through an access point.Foundational
• Intentional Radiator (IR)The RF device and cabling up to, but not including, the antenna.Intermediate
• Inter-Symbol Interference (ISI)Corruption that occurs when delayed multipath copies of one symbol overlap the next symbol.Advanced
• Internet of Things (IoT)Networked sensors, actuators, and devices that collect data and interact with the physical world.Foundational
• Inverse Square LawPower density falls in proportion to the square of the distance from the source.Intermediate
• Isotropic RadiatorA theoretical point source that radiates energy equally in every direction in a perfect sphere.Foundational
• Juniper Mist AIJuniper's AI-driven cloud management platform for wireless, wired, and SD-WAN, now part of HPE.Foundational
• Key Reinstallation Attack (KRACK)2017 attack that tricks clients into reinstalling an in-use key, resetting nonces and enabling decryption.Advanced
• Layer 3 RoamingA roam between APs in different IP subnets in which the client keeps its original IP address.Advanced
• Lightning ArrestorA device that shunts transient current from near lightning strikes to ground to protect equipment.Intermediate
• Lightweight Access Point (LAP)An AP that handles real-time radio functions while a controller manages configuration and control.Foundational
• Lightweight Extensible Authentication Protocol (LEAP)A legacy Cisco proprietary EAP method using unprotected MS-CHAP that is vulnerable to dictionary attacks.Intermediate
• Link BudgetAn accounting of all gains and losses from transmitter to receiver to predict received signal strength.Intermediate
• Local ModeDefault Cisco AP mode that serves clients and tunnels all client traffic to the WLC through CAPWAP.Intermediate
• Long-Term Evolution (LTE)The 3GPP 4G cellular standard using OFDMA downlink, SC-FDMA uplink, and an all-IP Evolved Packet Core.Foundational
• LoRaWANA low-power wide-area network protocol using LoRa chirp spread spectrum in sub-GHz unlicensed bands.Intermediate
• Low Power Indoor (LPI)A 6 GHz device class limited to indoor use and lower power without requiring AFC.Intermediate
• Low-Density Parity-Check (LDPC)A high-performance error-correcting code optional in 802.11n/ac and required for most 802.11ax/be rates.Advanced
• MAC Address RandomizationClient privacy feature that uses random MAC addresses for scanning or per network.Intermediate
• MAC Authentication Bypass (MAB)Authenticating a device by sending its MAC address to RADIUS when it cannot perform 802.1X.Intermediate
• MAC Protocol Data Unit (MPDU)The 802.11 MAC frame including header, frame body, and FCS.Advanced
• MAC Service Data Unit (MSDU)The Layer 3-7 payload handed down from LLC to the 802.11 MAC; maximum 2,304 bytes.Advanced
• Management FrameAn 802.11 frame type (type 0) used to join, leave, and maintain a BSS.Foundational
• Marvis ActionsMist's proactive dashboard that surfaces detected network issues and recommended fixes.Intermediate
• Marvis Virtual Network AssistantMist's conversational AI assistant for natural-language troubleshooting and network queries.Intermediate
• Maximal Ratio Combining (MRC)Receive technique that combines signals from multiple antennas to improve SNR.Advanced
• Medium Access Control (MAC)The 802.11 sublayer of Layer 2 that handles addressing, framing, medium access, and security.Foundational
• Meraki Air MarshalMeraki's built-in wireless intrusion detection and prevention system.Intermediate
• Meraki Auto RFMeraki's automatic channel and power optimization, enhanced by AI-RRM.Intermediate
• Meraki DashboardCisco Meraki's cloud management interface for wireless, switching, security, and cameras.Foundational
• Meraki MR Access PointCisco Meraki's cloud-managed wireless access point line.Intermediate
• Meraki Splash PageMeraki's captive portal options for guest onboarding, including click-through and sign-on pages.Intermediate
• Meraki SSID Addressing ModeThe Meraki per-SSID setting controlling how client IP addressing and traffic forwarding work.Advanced
• Mesh Access Point (MAP)A mesh AP that connects to the network wirelessly through a root AP or other mesh APs.Advanced
• Microsoft Challenge Handshake Authentication Protocol version 2 (MSCHAPv2)A password-based challenge-response protocol commonly used as the inner method of PEAP.Intermediate
• Millimeter Wave (mmWave)Radio spectrum from roughly 24 to 100 GHz used by 5G FR2 and 60 GHz Wi-Fi for very high capacity at short range.Intermediate
• Milliwatt (mW)One thousandth of a watt; the common linear unit of RF transmit power for Wi-Fi.Foundational
• MIMO NotationThe TxR:S format describing transmit chains, receive chains, and supported spatial streams.Intermediate
• Mist EdgeAn on-premises Juniper appliance or VM that terminates AP tunnels for central switching or guest anchoring.Advanced
• Mobility GroupA set of wireless controllers that share client context to support seamless roaming between them.Advanced
• ModulationVarying a carrier wave's amplitude, frequency, or phase to encode data.Foundational
• Modulation and Coding Scheme (MCS)An index combining modulation type and coding rate that determines a PHY data rate.Intermediate
• Monitor ModeAn AP mode that does not serve clients but scans all channels for rogues, intrusion, RRM, and location.Intermediate
• Multi-Link Device (MLD)A Wi-Fi 7 device with multiple affiliated stations or APs presenting a single MAC SAP for MLO.Advanced
• Multi-Link Operation (MLO)Wi-Fi 7 feature allowing a device to use multiple bands or channels simultaneously as one logical link.Intermediate
• Multi-RUWi-Fi 7 capability to assign more than one resource unit to a single user.Advanced
• Multi-User MIMO (MU-MIMO)MIMO in which an AP sends different spatial streams to multiple clients simultaneously.Intermediate
• Multicast Domain Name System Gateway (mDNS Gateway)A controller function that forwards Bonjour/mDNS service advertisements between VLANs.Advanced
• Multicast-to-UnicastConverting multicast frames into unicast frames per client so they can use higher rates and ACKs.Advanced
• MultipathTwo or more copies of the same signal arriving at a receiver at slightly different times via different paths.Foundational
• Multiple BSSID (MBSSID)A feature that advertises multiple BSSIDs in a single beacon to reduce overhead.Advanced
• Multiple-Input Multiple-Output (MIMO)Use of multiple transmit and receive antennas and radio chains to improve throughput and reliability.Foundational
• Near Field Communication (NFC)Very short-range (about 4 cm) 13.56 MHz wireless communication used for payments, access badges, and pairing.Foundational
• Near-Far ProblemA distant low-power station's signal being drowned out by nearby high-power stations.Advanced
• Neighbor ReportAn 802.11k list of nearby APs (BSSIDs, channels, capabilities) sent to a client to speed roaming.Intermediate
• Network Allocation Vector (NAV)The virtual carrier-sense timer stations set from the Duration field of frames they hear.Advanced
• Network SlicingCreating multiple logical end-to-end networks with distinct characteristics on shared 5G infrastructure.Advanced
• Noise FloorThe ambient level of background RF energy on a channel, measured in dBm.Foundational
• Non-Overlapping ChannelsChannels whose spectrum does not overlap, such as 1, 6, and 11 in the 2.4 GHz US band.Foundational
• Non-Wi-Fi InterferenceRF energy from devices that do not use 802.11, such as microwave ovens, Bluetooth, and cordless phones.Intermediate
• Null Data FrameA data frame with no body, used by clients to signal power-save state changes to the AP.Advanced
• Null Data Packet (NDP)A PHY frame without a data payload used for channel sounding and other measurements.Advanced
• NullingNear-total cancellation of a signal caused by multipath copies arriving 180 degrees out of phase.Advanced
• Omnidirectional AntennaAn antenna that radiates equally in all horizontal directions in a doughnut-shaped pattern.Foundational
• Open Radio Access Network (Open RAN)An architecture with open, interoperable interfaces between disaggregated RAN components from different vendors.Advanced
• Open System AuthenticationThe default 802.11 authentication method, a null exchange that always succeeds.Foundational
• Opportunistic Key Caching (OKC)A non-standard but widely supported fast roaming method where controllers share a client's PMK among APs.Intermediate
• Opportunistic Wireless Encryption (OWE)Standard (RFC 8110) providing encryption without authentication on open networks; certified as Wi-Fi Enhanced Open.Intermediate
• Optimized RoamingCisco feature that disassociates clients whose RSSI or data rate falls below thresholds to force roaming.Advanced
• Orthogonal Frequency-Division Multiple Access (OFDMA)Multi-user OFDM that divides a channel into resource units so several stations transmit simultaneously.Intermediate
• Orthogonal Frequency-Division Multiplexing (OFDM)Multicarrier modulation splitting a channel into many orthogonal subcarriers transmitted in parallel.Foundational
• Overlapping BSS Packet Detect (OBSS_PD)An adjustable CCA threshold for inter-BSS frames used in 802.11ax spatial reuse.Advanced
• Pairwise Master Key (PMK)The top-level key in the RSN pairwise hierarchy, derived from the PSK, SAE, or 802.1X/EAP authentication.Intermediate
• Pairwise Master Key Identifier (PMKID)A hash identifying a cached PMK, used in fast roaming and exploitable for clientless WPA2-PSK cracking.Advanced
• Pairwise Transient Key (PTK)The per-session unicast key derived in the 4-way handshake, split into KCK, KEK, and TK.Advanced
• Parabolic Dish AntennaA highly directional dish-shaped antenna that focuses RF into a pencil beam.Intermediate
• Passive ScanningDiscovering APs by listening for beacon frames on each channel.Intermediate
• Patch AntennaA flat semi-directional antenna that radiates forward in a hemispherical-to-cone pattern.Intermediate
• Peer-to-PeerDirect communication between wireless client devices.Intermediate
• Peer-to-Peer BlockingAn AP or controller setting that prevents wireless clients from communicating directly with each other.Intermediate
• PhaseThe position of a point in a wave's cycle, measured in degrees, relative to another wave or reference.Intermediate
• Phase Shift Keying (PSK)Modulation that represents data by changing the carrier's phase.Intermediate
• Physical Layer Convergence Procedure (PLCP)The upper PHY sublayer that prepares MAC frames for transmission by adding a preamble and header.Advanced
• Pilot SubcarrierAn OFDM subcarrier carrying known reference data used for phase and frequency tracking.Advanced
• PLCP Protocol Data Unit (PPDU)The PHY-layer frame consisting of preamble, PHY header, and the PSDU (MAC frame).Advanced
• PMK Caching802.11i fast reconnection where a client returning to a previously used AP reuses the cached PMK.Intermediate
• Point-to-Multipoint Bridge (PtMP)A hub bridge with an omnidirectional or sector antenna connecting several remote sites.Intermediate
• Point-to-Point Bridge (PtP)A wireless link connecting two networks, typically between buildings, using directional antennas.Intermediate
• PolarizationThe orientation of an antenna's electric field: vertical, horizontal, or circular.Intermediate
• Policy ProfileThe Catalyst 9800 object defining client policy such as VLAN, ACLs, QoS, AAA override, and switching mode.Intermediate
• Policy TagA Catalyst 9800 object that maps WLAN profiles to policy profiles and is assigned to APs.Advanced
• Power Save Mode802.11 mechanisms allowing clients to sleep while the AP buffers their traffic.Intermediate
• PreambleTraining fields at the start of a PPDU that let receivers detect, synchronize to, and estimate a signal.Advanced
• Preamble PuncturingTransmitting a wide channel while skipping (puncturing) a busy or unavailable 20 MHz subchannel.Advanced
• Predictive Site SurveyA software-modeled WLAN design built from floor plans, wall attenuation values, and AP models.Intermediate
• Preferred Scanning Channel (PSC)One of fifteen 6 GHz 20-MHz channels (every fourth channel) that clients scan to discover APs.Intermediate
• Primary ChannelThe 20 MHz channel within a wider bonded channel on which beacons and control frames are sent.Advanced
• Private Cellular NetworkAn enterprise-owned LTE or 5G network using dedicated or shared spectrum, its own core, and enterprise SIMs.Intermediate
• Probe RequestA management frame sent by a client to discover nearby APs, either for a specific SSID or any SSID.Foundational
• Probe ResponseA unicast management frame from an AP answering a probe request with BSS information.Foundational
• Protection MechanismMethods such as RTS/CTS and CTS-to-self that make legacy stations defer during newer PHY transmissions.Intermediate
• PS-PollA control frame sent by a power-saving client to retrieve one buffered frame from the AP.Advanced
• QoS ProfileCisco precious-metal QoS levels (Platinum, Gold, Silver, Bronze) that cap the maximum priority per WLAN.Advanced
• Quadrature Amplitude Modulation (QAM)Modulation that varies both amplitude and phase to encode multiple bits per symbol.Intermediate
• Quadrature Phase Shift Keying (QPSK)PSK using four phase states to carry 2 bits per symbol.Intermediate
• Quality of Service Data Frame (QoS Data)An 802.11 data frame subtype with a QoS Control field containing the Traffic Identifier.Advanced
• Radio Frequency (RF)Electromagnetic energy in the roughly 3 kHz to 300 GHz range used to carry data wirelessly.Foundational
• Radio Frequency Identification (RFID)Technology that uses radio to identify and track tags, in LF, HF, and UHF bands, passive or active.Foundational
• Radio Line of Sight (RLoS)A clear RF path that includes both visual line of sight and an unobstructed Fresnel zone.Intermediate
• Radio Resource Management (RRM)Automated management of AP channels, transmit power, and coverage based on measured RF conditions.Intermediate
• Radiotap HeaderA pseudo-header added by capture drivers that records RF metadata such as channel, data rate, and signal strength.Advanced
• Random BackoffA random number of slot times a station waits after the medium is idle before transmitting.Intermediate
• Rayleigh FadingRapid signal-strength variation caused by multipath when there is no dominant line-of-sight path.Advanced
• Real-Time Location System (RTLS)A system that tracks the location of devices or tags in real time using Wi-Fi, BLE, UWB, or other signals.Intermediate
• ReassociationThe process by which a client moves its association from one AP to another within an ESS.Intermediate
• Received Signal Strength Indicator (RSSI)A measurement of received signal power, usually reported in dBm by Wi-Fi radios.Foundational
• Receiver SensitivityThe weakest signal a receiver can decode at a specified data rate and error rate.Intermediate
• Reduced Neighbor Report (RNR)An information element in 2.4/5 GHz beacons and probe responses advertising co-located 6 GHz BSSs.Advanced
• Reference Signal Received Power (RSRP)LTE and 5G measurement of the average power of reference signals from a cell, in dBm.Intermediate
• ReflectionRF bouncing off a smooth surface larger than the wavelength, such as metal or glass.Foundational
• RefractionBending of an RF wave as it passes between media of different densities.Intermediate
• Regulatory DomainThe set of allowed frequencies, channels, and power limits for a country or region.Foundational
• Request to Send / Clear to Send (RTS/CTS)A control frame handshake that reserves the medium before a data transmission.Intermediate
• Resource Unit (RU)A group of OFDMA subcarriers (tones) allocated to one user in an 802.11ax/be transmission.Intermediate
• Retry RateThe percentage of frames retransmitted because no acknowledgment was received.Intermediate
• Return LossThe ratio in dB of forward power to reflected power caused by impedance mismatch.Advanced
• RF ConnectorA coaxial connector such as N-type, RP-SMA, RP-TNC, or SMA used between radios, cables, and antennas.Intermediate
• RF TagA Catalyst 9800 object that assigns RF profiles for each band to APs.Advanced
• RoamingA client moving its association from one AP to another in the same ESS while keeping connectivity.Foundational
• Robust Security Network (RSN)An 802.11i network that allows only RSN associations using the 4-way handshake and CCMP/GCMP.Intermediate
• Root Access Point (RAP)The mesh AP with a wired connection that serves as the gateway for wireless mesh APs.Advanced
• Rule of 10s and 3sMental math shortcut: +3 dB doubles power, -3 dB halves it, +10 dB multiplies by 10, -10 dB divides by 10.Foundational
• SA QueryA PMF procedure that verifies an existing security association before accepting a new association attempt.Advanced
• ScatteringReflection of RF in many directions when it strikes uneven surfaces or small particles.Intermediate
• Sector AntennaA high-gain antenna covering a pie-slice sector, often grouped to form 360-degree coverage.Intermediate
• Semi-Directional AntennaAn antenna that focuses energy in one general direction, such as patch, panel, and Yagi antennas.Intermediate
• Service Level Expectation (SLE)Mist metrics measuring user experience against configurable thresholds, such as Time to Connect and Coverage.Intermediate
• Service Set Identifier (SSID)The human-readable name of a wireless network, up to 32 octets.Foundational
• Shared Key AuthenticationLegacy WEP-based 802.11 authentication using a challenge-response with the static WEP key.Intermediate
• Short Interframe Space (SIFS)The shortest 802.11 interframe space, used before ACKs, CTS, and frames in a TXOP.Advanced
• Side LobeUnintended secondary radiation lobes outside an antenna's main beam.Advanced
• Signal-to-Interference-plus-Noise Ratio (SINR)The ratio of desired signal power to the sum of interference and noise.Intermediate
• Signal-to-Noise Ratio (SNR)The difference in dB between received signal strength and the noise floor.Foundational
• Single-User MIMO (SU-MIMO)MIMO in which all spatial streams of a transmission go to one client.Intermediate
• Site SurveyAssessment of the RF environment to design, deploy, or validate a WLAN for coverage and capacity.Foundational
• Site TagA Catalyst 9800 object that assigns an AP join profile and, for remote sites, a flex profile.Advanced
• Six Decibel RuleEach doubling of distance causes approximately 6 dB of additional free space path loss.Intermediate
• Slot TimeThe basic time unit for 802.11 backoff counting: 9 microseconds for OFDM or 20 microseconds for DSSS.Advanced
• Smart AntennaAn antenna system that dynamically adjusts its pattern to focus energy toward clients.Advanced
• Sniffer ModeAn AP mode that captures frames on one channel and forwards them to a remote packet analyzer.Intermediate
• Space-Time Block Coding (STBC)Transmitting redundant copies of a data stream across multiple antennas to improve reliability.Advanced
• Spatial Multiplexing (SM)Sending multiple unique data streams over the same channel at the same time using different antennas.Intermediate
• Spatial Reuse802.11ax mechanisms allowing transmission during weak overlapping-BSS frames to increase channel reuse.Advanced
• Spatial Stream (SS)An independent data stream transmitted simultaneously from separate antennas on the same channel.Intermediate
• Spectrum AnalyzerA tool that measures RF energy across frequencies to identify interference, regardless of protocol.Intermediate
• Split MAC ArchitectureDivision of 802.11 MAC functions between a lightweight AP (real-time) and a controller (non-real-time).Intermediate
• Spread SpectrumTransmitting a signal over a wider bandwidth than strictly required to improve resilience.Intermediate
• Standard Power (SP)A 6 GHz device class allowed higher power indoors or outdoors under AFC control.Advanced
• Sticky ClientA client that remains associated to a distant AP despite better APs being available.Intermediate
• SubcarrierA narrow frequency component of an OFDM channel carrying data, pilot, or null signals.Intermediate
• Subscriber Identity Module (SIM)A secure smart card or embedded chip storing a subscriber's identity (IMSI) and authentication keys.Foundational
• SupplicantThe client software or device requesting network access in an 802.1X exchange.Foundational
• Supported RateA data rate the BSS allows clients to use but does not require.Intermediate
• SymbolThe unit of transmitted information on an RF carrier; one modulation state that represents one or more bits.Intermediate
• System Operating Margin (SOM)The actual difference between received signal level and the receiver's sensitivity.Intermediate
• Target Beacon Transmission Time (TBTT)The scheduled time at which an AP intends to transmit a beacon.Advanced
• Target Wake Time (TWT)An 802.11ax power-saving feature in which client and AP negotiate scheduled wake times.Intermediate
• ThreadAn IPv6-based low-power mesh protocol over 802.15.4 using 6LoWPAN, used as a transport for Matter.Advanced
• Time Division Duplex (TDD)Sharing one frequency for uplink and downlink by alternating in time.Intermediate
• Time Unit (TU)An 802.11 time measurement equal to 1,024 microseconds.Advanced
• Traffic Indication Map (TIM)A beacon field indicating which power-saving stations have buffered unicast frames at the AP.Advanced
• Transmit Beamforming (TxBF)Adjusting phase across multiple antennas so signals combine constructively at a specific receiver.Intermediate
• Transmit Opportunity (TXOP)A bounded interval during which a station may send multiple frames after winning contention.Advanced
• Transmit Power Control (TPC)Adjusting transmit power to reduce interference, defined by 802.11h and used by RRM algorithms.Intermediate
• Trigger FrameAn 802.11ax control frame that solicits and schedules simultaneous uplink transmissions from multiple clients.Advanced
• Tunnel Extensible Authentication Protocol (TEAP)An IETF tunneled EAP method (RFC 7170) supporting EAP chaining of machine and user authentication.Advanced
• Ultra-Wideband (UWB)A short-range radio technology using very wide bandwidth pulses (500 MHz or more) for precise time-of-flight ranging.Advanced
• Unlicensed National Information Infrastructure (U-NII)FCC-defined unlicensed sub-bands in 5 GHz (U-NII-1 to U-NII-4) and 6 GHz (U-NII-5 to U-NII-8).Intermediate
• Unscheduled Automatic Power Save Delivery (U-APSD)WMM Power Save method where a client's uplink frame triggers delivery of buffered downlink frames.Advanced
• UpfadeSignal-strength increase caused by multipath copies arriving nearly in phase.Advanced
• User Priority (UP)The 802.1D-based 0-7 priority value carried in 802.11 QoS data frames.Advanced
• Very High Throughput (VHT)The 802.11ac PHY and MAC enhancements.Intermediate
• Very Low Power (VLP)A 6 GHz device class for short-range portable use indoors and outdoors without AFC.Advanced
• Virtual Bluetooth Low Energy (vBLE)Mist technology using a directional BLE antenna array in APs to create virtual beacons for indoor location.Advanced
• Voltage Standing Wave Ratio (VSWR)The ratio describing impedance mismatch between transmitter, cable, and antenna; 1:1 is perfect.Advanced
• Wall AttenuationThe signal loss in dB attributed to specific building materials in a WLAN design.Intermediate
• WavelengthThe physical distance an RF wave travels during one complete cycle.Foundational
• Wi-Fi 6EWi-Fi 6 (802.11ax) devices that can operate in the 6 GHz band.Foundational
• Wi-Fi 7Wi-Fi Alliance name for 802.11be devices, emphasizing multi-link, wider channels, and lower latency.Foundational
• Wi-Fi Agile MultibandWi-Fi Alliance certification combining 802.11k, 802.11v, 802.11r, and MBO for intelligent steering.Advanced
• Wi-Fi Alliance (WFA)Industry organization that certifies 802.11 product interoperability and owns the Wi-Fi trademark.Foundational
• Wi-Fi CERTIFIEDThe Wi-Fi Alliance certification mark indicating a product passed interoperability testing.Intermediate
• Wi-Fi DirectWi-Fi Alliance certification for device-to-device connections where one device acts as a soft AP group owner.Intermediate
• Wi-Fi Easy ConnectWi-Fi Alliance onboarding based on the Device Provisioning Protocol, typically by scanning a QR code.Advanced
• Wi-Fi Generation NamesWi-Fi Alliance consumer names mapping standards to generations: Wi-Fi 4 (n), 5 (ac), 6 (ax), 7 (be).Foundational
• Wi-Fi HaLowWi-Fi Alliance name for 802.11ah sub-1 GHz long-range low-power Wi-Fi.Intermediate
• Wi-Fi Multimedia (WMM)Wi-Fi Alliance certification of 802.11e EDCA QoS with four access categories.Intermediate
• Wi-Fi Protected Access (WPA)The 2003 Wi-Fi Alliance interim security certification based on a draft of 802.11i, using TKIP.Foundational
• Wi-Fi Protected Access 2 (WPA2)Wi-Fi Alliance security certification implementing 802.11i with AES-CCMP, in Personal (PSK) and Enterprise (802.1X) modes.Foundational
• Wi-Fi Protected Setup (WPS)A simplified setup method using a PIN or push button, vulnerable to brute-force and Pixie Dust attacks.Foundational
• Wi-Fi SensingUsing changes in Wi-Fi channel measurements to detect motion, presence, or activity.Advanced
• Wireless Distribution System (WDS)Wireless interconnection of APs using four-address frames.Advanced
• Wireless Intrusion Prevention System (WIPS)A system that monitors RF for rogue devices and attacks and can take containment actions.Intermediate
• Wireless LAN Controller (WLC)A device or virtual appliance that centrally manages lightweight APs, RF, security, and client policy.Foundational
• Wireless Mesh Network (WMN)A WLAN in which APs use wireless backhaul links to reach a wired-connected root AP.Intermediate
• WLAN ProfileThe Catalyst 9800 object defining an SSID and its Layer 2 and Layer 3 security settings.Intermediate
• WPA3 Transition ModeA mixed mode where one SSID accepts both WPA2-PSK and WPA3-SAE clients, with PMF optional.Intermediate
• WPA3-Enterprise 192-Bit ModeOptional WPA3-Enterprise mode aligned with CNSA, using GCMP-256, HMAC-SHA-384, and EAP-TLS with 384-bit ECC or 3072-bit RSA.Advanced
• WxLAN PolicyMist's label-based access policy applied at the AP to control traffic between users and resources.Advanced
• Yagi AntennaA semi-directional antenna with a driven element and parasitic directors and a reflector.Intermediate
• ZigbeeA low-power mesh networking standard built on IEEE 802.15.4, mostly in 2.4 GHz at up to 250 kbps.Intermediate