802.11 wifi glossary terms acronyms

So many abbreviations!

The Wi-Fi standards 802.11x use so many abbreviations that it makes it extremely frustrating to read any text on the subject. For some reason authors seem to like using too many TLAs all over the text without expanding or explaining them. So I thought this collection of common terms and concise definitions would be a handy reference.

This is a glossary of acronyms only. To be included, the term must be a pesky acronym related to 802.11X technology. See this link for a short glossary including some non-acronyms.

Feel free to add more in the comments section.

1-9

10110111000

This is a Barker code which is a spreading code- not an acronym of course but interesting enough to include here. This particular one is of length 11, and is used in HR/DSSS coding. It has a low autocorrelation sequence which is linked with low side-lobe. The code has special characteristics. The longest Barker sequence is thought to be 13.

1FZ

The first Fresnel Zone (pronounced frey-nell). A 3D elliptical LOS clearance zone between two antennas. The shape of 1FZ is specified by a maximum radius.

Assuming a flat-Earth:

                  ________

1FZradius = 72.05·√(D/4/f))

1FZ is in feet and D is distance in miles between antennas. 
f is frequency in GHz.

For metric units, D in Km and result in meters use 17.32

                  ________

1FZradius = 17.32·√(D/4/f))


If more than 40% of 1FZ is blocked then the link won't function.

To take account of Earth's bulge which is significant for 
D > 10Km (7 miles)

Height of bulge = D·D/8


16-QAM

16 Quadrature Amplitude Modulation. 4 bits are transmitted within one symbol period.

2GFSK

Two-level GFSK. (See GFSK) Uses two frequencies. 1MBps.

2PSK

See BPSK.

3G

Third Generation. Mobile phone technology. Requires 50-20 MHz bandwitdth, and could operate at 2000 Mhz or 2100 MHz. UMTS specifies the bands 1900-2025 MHz and 2110-2200 MHz for 3G transmission. The satellite service uses the bands 1980-2010 MHz (uplink), and 2170-2200 MHz (downlink). This leaves the 1900-1980 MHz, 2010-2025 MHz, and 2110-2170 MHz bands for terrestrial UMTS

4GFSK

Four-level GFSK. (See GFSK) Uses 4 frequencies. 2Mbps

802.2

See LCC.

802.3

Ethernet.

A-C

ABC
DEF
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KLM
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TUV
WXYZ

a x b: c

When multiple data-streams are implemented, this is done using multiple antennas.

(a) = maximum number of transmit antennas.

(b) = maximum number of receive antennas.

(c) = maximum number of data stream.

4 x 4: 4 is the maximum for 802.11n at an OTA of 600 Mb/s

AAA

Authentication, Authorization, and Accounting.

ACMA

Australian Communications and Media Authority. A regulatory body.

ACK

Acknowledgement. This is a symbol sent from the receiver to the sender to positively qualify the transmission.

AES

Advanced Encryption Standard

AID

Association IDentifier. A collection of these makes a TIM. During power-save mode, frames need to be buffered and they are indexed using AIDs. AIDs (in the TIM) are predictably accessible because they are inside beacon frames which are regularly transmitted.

AC

Alternating Current. Electrons net drift is zero but oscillate about a mean. Compare with DC.

AFH

Adaptive Frequency Hopping - as used in modified Bluetooth to help avoid interference with other 802.11, 2.4 GHz devices. Original Bluetooth indiscriminately and randomly uses 79 of 83.5 available channels, 1600 times a second which can result in interference with other devices. AFH tests the air using RSSI and/or Packet Error Rate (PER) to avoid channels that are probably in use down to using a minimum of 20 channels.

ANSI

American National Standards Institute.

AM

Amplitude Modulation. Signal is encoded in the amplitude of a carrier signal. The carrier signal frequency is significantly higher than the highest signal frequency. Contrast FM.

AP

Access point. This is the station (STA) which uses wireless 802.11 to link internal clients to an external service like a wireless enabled laptop to the Internet via a broadband connection.

ARIB

(Japan) Association of Radio Industries and Businesses. A regulatory body.

ASCII

American Standard Code for Information Interchange.

ASK

Amplitude Shift Keying. This is the digital implementation of the analogue amplitude modulation.

ATIM

Ad-Hoc Traffic Information Message. Interchangeable, but soon to be superseded by the term "Announcement Traffic Indication Message".

BER

Bit Error Rate

BPSK

Binary Phase Shit Keying. a.k.a. PRK (Phase Reversal Keying) or 2PSK. Simple phase shift keying using two phases, 180 degrees apart.

BSA

Basic Service Area. This contains members of a BSS.

BSS

Basic Service Set. This is a group of stations (STNs).

BSSID

Basic Service Set IDentifier which is a 48-bit globally unique identifier for a BSS.

CAM

Continually Aware Mode. This is a vendor-term meaning 'active mode'. See PS.

CCA

Clear Channel Assessment. This is done as part of CSMA/CA where the STN checks the RF energy levels to see if others are currently using the desired frequencies. It only partly works because two STNs that communicate via an AP might no be able to hear one another. (Hidden node problem). See also NAV.

CCK

Complimentary Code Keying. A phase modulation technique. 802.11b uses CCK at 5.5 or 11 Mbit/s within 2.400 GHz to 2.4835 GHz. 802.11g uses CCK when operating at 802.11b speeds. See also HR/DSSS.

CD

Collision Detection. See CSMA/CD and CSMA/CA

CF

Compact Flash. The interface for this also allows an 802.11 device.

CCMP

Counter Mode with Cipher Block Chaining Message Authentication Code Protocol. This is a mandatory part of WPA2 and optional in WPA. It uses AES. It replaces TKIP and WEP.


CLI

Command Line Interface.

CRC

Cyclic Redundancy Check. A type of non-cryptographic hash which detects errors in transmission. It is transmitted with the data, and re-computed at the receiver. If the transmitted CRC and the recomputed CRC match then the likelihood of an error in transmission is extremely low.

CSMA/CA

Carrier Sense Multiple Access with Collision Avoidance. This means "listen before talk . Before transmitting, a station first senses the radio channel and if the medium is not busy, then it announces that it will transmit, it then transmits. Then if a collision is later detected, both devices go off line for a random time. When collisions happen, the whole frame must be retransmitted. This is why it is more efficient to avoid them when possible.

CSMA/CD

Carrier Sense Multiple Access with Collision Detection. Multiple devices share a communications medium by sending as soon as the communications channel is detected as silent. They then monitor the line for a collision. If a collision is detected, then it uses a random backoff time before resending. Collisions are more likely than in CSMA/CA but a frame can be aborted early to minimize overhead.

CTS

Clear to send. This is a flow control operation.

CWNA

Certified Wireless Network Administrator. An industry agnostic accreditation.

CWSP

Certified Wireless Security Professional

CWNT

Certified Wireless Network Trainer

CWTS

Certified Wireless Technology Specialist

CWNE

Certified Wireless Network Expert

Can 802.11n replace the Edge network?

D-F

ABC
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dB

Decibel. This is the logarithm of a dimensionless ratio of a power with a reference. It is specifically

10·LOG10(P1/P0).

Where P0 is the reference.

dBd

Decibels to Dipole. RF signal strength compared to practical dipole. SQRT(2) times more than dBi.

dBi

Decibels to isotropic. RF signal strength compared to a theoretical ideal isotropic radiator.

dBm

Decibels milliwats. 0dBm = 1 milliwatt. 3dBm increase doubles the power so 3dBm = 2 milliwatt.

DBPSK

Differential Binary Phase Shift Keying. This is a 1 Mbps phase modulation used in DSSS. It has good immunity to interference. Phases used are 180 degrees apart for binary 0 and 1.

DC

Direct Current. Electrons drift and favor one direction. Compare with AC.

DCF

Distributed Coordination Function. This access method is an 802.11 implementation of CSMA/CD. Contrast with PCF and HCF. It is is a fundamental MAC technique that uses random backoff times within a CSMA/CA scheme.

DES

Data (Digital) Encryption Standard.

DFS

Dynamic Frequency Selection. 802.11h. Devices must comply with ITU regulations in the 5GHz band. 802.11h uses DFS and TPC. When the device detects another on the same channel it switches channels to avoid conflict. In particular - plays better with satellites in Europe.

DFT

Discrete Fourier Transform.

DLL

Data Link Layer. This is layer 2 of the OSI model. It detects and corrects errors in the physical layer. This layer is sub-divided into the LCC and MAC layers.

DoS

Denial of Service. This is any malicious attack on a system which denies the legitimate users access to the service under attack.

DPSK.

Differential Phase Shift Keying. See also DBPSK and DQPSK which are examples of DPSK.

DQPSK

Differential Quadrature Phase Shift Keying. This is a 2 Mbps phase modulation used in DSSS. It is sensitive to multipath interference and may throttle down to 1 Mbps. Phases used are { 0 , 90 , 180 , 270 } degrees, mapping on to { 00 , 01 , 10 , 11 } See also DBPSK.

DRS

Dynamic Rate Switching. The standards-based way to refer to "Automatic Rate Switching" (ARS) or "Dynamic Rate Selection" (DRS). When in operation, the data rate, coding and modulation types are variable.

DS

Distribution System. This is how an access points communicate. They exchange frames for:

  • stations inside a BSS,
  • mobile stations as they move between BSSs.
  • connection with a wired network.

or

a Distribution Service which is the service that delivers MSDUs in a Distribution System.

DSL

Digital Subscriber Line. (formerly Digital Subscriber Loop). 384 to 20 Mbps over POTS, sharing the line with regular telephone by using higher frequencies and a filter. See also: More types.

DSL

Digital Signal Processor.

DSSS

Direct-Sequence Spread Spectrum. This is a modulation technique. By rapidly mixing the original signal with a synchronized pseudo-random stream at the source and destination , the energy of the original signal is also spread through the band. It enhances the signal to noise ratio. Each chip from the random stream is smaller than the signal bit and so it uses several chips per bit. In DSSS. multiple copies of the data are sent. This redundancy improves overall throughput under noisy conditions at low power.

DSSS-ODFM

Direct-Sequence Spread Spectrum - Orthogonal Division Frequency Multiplexing. Optional in 802.11g. Hybrid scheme combines DSSS preamble+header with ODFM payload transmission. Data rates are {6,9,12,18,24,36,48,54} Mbps.

DTIM

Delivery Traffic Indication Message. This TIM announces broadcast/multicast frames that are in the Tx buffer.

EAP

Extensible Authentication Protocol. There are several mothods: EAP-MD5, EAP-OTP, EAP-GTC, EAP-TLS, EAP-IKEv2, EAP-SIM, and EAP-AKA, EAP-FAST and some vendor specific methods.

EDGE

Enhanced Data Rates for GSM Evolution. It's a 3G technology, backward-compatible digital mobile phone technology as an extension on top of standard GSM.

EDCA

an 802.11e (QoS) enhancement of DCF. This defines eight traffic priority levels (0-7) defined by the User Priority value (UP).

EEG

Enterprise Encryption Gateway. An IEEE OSI Layer 2 encryption device like a VPN but using hardware. It has strong authentication and encryption across a wireless medium.

EIRP

Equivalent Isotropically Radiated Power. This is a measure of a signal's strength or power when transmitted. Here is a calculator.

EIRP (dBm) = Intentional Radiated Power (dBm) + Antenna Gain (dBi)

ERP

Extended Rate Physical Layer (802.11g). Also see Non-ERP.

ERP-DSSS

Extended Rate Physical Layer - Direct Sequence Spread Spectrum. Required by 802.11g.

ERP-OFDM

Extended Rate Physical Layer - Orthogonal Frequency Division Multiplexing.

ERP/ODFM

Extended Rate Physical Layer / Orthogonal Frequency Division Multiplexing. i.e. what used to be called 802.11a/g where there are two PHYs involved: ERP and ODFM.

See also this external link.

ERP-PBCC

Extended Rate Physical Layer -Packet Binary Convolutional Code. Optional in 802.11g. The payload is encoded using a 256-state PBCC.

ESS

Extended Service Set. An ESS is a set of BSSs to extend area coverage.

ESSID

Extended Service Set Identifier. This is really just an SSID. People use the term when talking about multi-access point setups. (The flawed rationale is that BSS uses SSID therefore ESS uses ESSID). There is no ESSID in the official specifications.

FCC

Federal Communications Commission. (USA)

FFT

Fast Fourier Transform.

FHSS

Frequency Hopping Spread Spectrum. Obsolete 1 and 2 Mbps 2.4GHz PHY - although Bluetooth uses it.

FM

Frequency Modulation.Signal is encoded in the frequency of a carrier signal. The carrier signal frequency is significantly higher than the highest signal frequency. Contrast AM.

FPGA

Field Programmable Gate Array. A way to construct a program in hardware and alter it when the device is in practical use.

FSK

Frequency Shift Keying.

FSL

Free Space Loss. As an RF signal travels away from the source it diverges. The formula for FSL is:

32.44 + 20·Log10(d) + 20·Log10(f)

The constant 32.44 demands units of distance d in Km and frequency f in MHz. See this derivation.

 

FSR

Fast/Secure Roaming. This is when a handoff happens from one AP to another in an ESS using only a 4-way handshake. E.G. Automonmous Access Points (APs) can use CCMP with a pre authentication method and opportunistic PMK caching. This gives a Robust Security Network (RSN) feature.

FTP

File Transfer Protocol. This is an insecure method of transferring data. Password and user name is in the clear, and there is no encryption.

FTTB

Fiber To The Building. Compare FTTH, FTTN, FTTP.

FTTH

Fiber To The Home. Compare FTTB,FTTN, FTTP.

FTTN

Fiber To The Node. The next generation of broadband technology up from ADSL. Fiber connects main exchange to mini-exchanges which then deliver via VDSL. Compare FTTB, FTTH, FTTP,

FTTP

Fiber To The Premises. Compare FTTB, FTTH, FTTN.

Modulation Scheme vs. Data Rate

Modulation | Data Rate
----------------------
DBPSK      |     6 Mbps
DBPSK      |     9
DQPSK      |    12
DQPSK      |    18
16-QAM     |    24
16-QAM     |    36
64-QAM     |    48
64-QAM     |    54

16 and 64 represent phase
shifts in use.

G-J

ABC
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KLM
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WXYZ

GFSK

Gaussian Frequency Shift Keying. This is FSK with pulse shaping to limit the spectral width and thus reduce inter-symbol interference that might be caused by the communications channel.

GHz

See Hz.

GPSK

Gaussian Phase Shift Keying. This is a PMD used in FHSS.

GSM

Global System for Mobile communications. 2G mobile phones. Popular use provides international roaming for mobile phones. Contrast with 3G EDGE.

HCF

Hybrid Coordination Function. Compare with DCF and PCF. This provides a preemptive capability for QAPs in a QoS environment.

HCI

Host Controller Interface. This Bluetooth layer provides a command interface to the baseband controller and link manager.

control and negotiate all aspects of the operation of the Bluetooth connection

HR/DSSS

High Rate Direct Sequence Spread Spectrum. (802.11b). Uses combination of DQPSK and CCK to encode 4 or 8 bits in one symbol period.

HSPA

High Speed Packet Access. A 3G broadband data technology.

HT

High Throughput - as in "HT PHY", high throughput physical. (802.11n)

HT-OFDM

High Throughput OFDM.

HTTP

Hypertext Transfer Protocol. Non-encrypted download of Web pages.

HTTPS

Hypertext Transfer Protocol Secure. This uses a transport protocol that provides encryption. Typically TLS or SSL.

Hz

Hertz. 1 Hz is one complete cycle in a second. 45 GHz is 45 billion cycles in one second where billion=10^9.

IAPP

Inter-Access Point Protocol. Trial designed for the enforcement of unique association throughout an ESS. 802.11F has been withdrawn.

IBSS

Independent Basic Service Set. This is an Ad-Hoc (peer to peer) network.

ID

See IE.

IDFT

Inverse Discrete Fourier Transform.

IDSN

A circuit-switched Integrated services digital network. Integrates speech and data on the same POTS lines. It comes in Basic, Primary and Broadband speeds.

From Wikipedia, the free encyclopedia

IE

Information Element. This is a field in a management frame. IEs are a device's way to transfer descriptive information about itself. It is a flexible structure but consists of three fields:

[ID][Len][Value]

See also: TLV.

IEEE

Institute of Electrical and Electronic Engineers. A leading professional association for the advancement of technology

IETF

Internet Engineering Task Force. A standards development team. "The mission of the IETF is make the Internet work better by producing high quality, relevant technical documents that influence the way people design, use, and manage the Internet."

IETF RFC 2865

Internet Engineering Task Force, Request for Comment, (RFC) 3748 describes RADIUS.

IETF RFC 3748

Internet Engineering Task Force, Request for Comment, (RFC) 3748 describes EAP.

IF

Information Field. (aka fixed field).

IKE

Internet Key Exchange. Used by IPsec.

IFFT

Inverse Fast Fourier Transform.

IMAP

Internet Message Authentication Protocol for receiving email where an IMAP connection results in email headers downloaded from the server. Individual email content is downloaded on demand. Contrast with POP.

IPsec

Internet Protocol SECurity. An encrypted tunnel. See also IKE.

IR

Infra Red.

ISI

Inter Symbol Interference. Typically in an indoor environment where reflections cause multipath interference, delayed versions of earlier bits can interfere with present bits.

ISM

Industrial Scientific Medical. Frequency band 2400-2500 MHz license-Free.

ISO

Not an acronym - International Organization for Standards. This comes from a Greek word isos - meaning 'equal'.

ISP

Internet Service Provider.

ITS

Intelligent Transportation System. P802.11p addresses a need for high speed vehicles to exchange data at up to 200km/h over 1Km.

ITU-R

International Telecommunication Union. Formerly CCIR. Deals with the standardization of wireless communication.

IV

Initialization Vector. This is a set of bits used by a stream cipher or a block cipher in streaming mode to make a unique stream independent from other streams produced by the same encryption key without re-keying.

K-M

ABC
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KLM
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TUV
WXYZ

LAN

Local Area Network.

LDAP

Lightweight Directory Access Protocol. This is a read-optimized flexible database especially suitable for storing credentials used by authentication schemes.

LOS

Line of Sight. This means that there are no obstructions in a straight line sighting from transmitter to receiver. This may refer to visible sighting or RF sighting.

LLC

Logical Link Control. The Data Link Layer has two sub-layers. The LLC is one of them. The other is the MAC layer. Note: Ethernet is allowed to skip the LLC. The LLC is also known as 802.2

LMP

Link Manager Protocol. Controls and negotiates a Bluetooth connection.

MAC

Medium Access Control. This manages and maintains communications between 802.11 stations (STA) [ Also : MAC address which is a unique identifier associated with a specific interface. At layer 2 of the OSI model, the MAC is analogous to the IP address used at layer 3]

MAN

Metropolitan Area Network. See also WMAN.

MIC

(Japanese) Ministry of Internal Affairs and Communications. A regulatory body.

MIMO

Multiple-input, Multiple output. Multiple antennas at transmitter and receiver improves communication performance. The spacial separation of the antennas allows better discrimination and ability to take advantage of multiple-path transmission. Normally, when a signal gets reflected, split and bounced about from source to destination, the arriving signal is degraded but MIMO can sort this out and use the multiple paths to get around obstacles.

MK

Master Key. When a station (STA) authenticates and the associated Access Point (AP) contacts an Authentication Server (AS) a session master key is established between the STN and the AS.

MMDS

Microwave Multipoint Distribution System.

MMPDU

Medium Access Control (MAC) Management Protocol Data Unit.

MPDU

Medium Access Control (MAC) Protocol Data Unit. This is made up of a a payload, (MSDU), a MAC header, and a trailer.

MSDU

Medium Access Control (MAC) Service Data Unit. This is made from data provided by the LLC or layers above the DLL. It is always ≤ 2304 bytes.

MU

Mobile Unit.

mW

Milliwatt. See W (Watt).

NIC

Network Interface Card.

N - P

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NAC

Network Access Control. An appliance based security device that is capable of enforcing patch levels into devices that request connectivity as in a captive-portal solution. It enforces security policy on the end devices.

NAV

A virtual carrier sensing mechanism that limits the need for physical carrier sensing at the air interface in order to save power. It is a counter. This counter is read by the stations and then decremented during the time that the air is busy. During this time, battery-powered stations can turn off transmission devices to save power. NAV is part of the implmentation of "Virtual Carrier Sense" which supplements CCA in CSMA/CA.

Non-ERP

Non-Extended Rate Physical. Stations that are not extended rate, but are inter-operable with those that are. [ DSSS and HR/DSSS ]

ODFM

Orthogonal Frequency Division Multiplexing (802.11a). This is a frequency division multiplexing (FDM) scheme used as a modulation technique. The input data is parallelized over several orthogonal sub-carriers. Each sub-carrier modulates at a lower rate which in aggregate gives good throughput, individually each sub-channel is more resistant to problems in the channel. Mandatory data rate specifications are {6,12,24} Mbps in the 5GHz UNII bands. Capable of {6,9,12,18,24,36,48} Mbps. In contrast to DSSS it uses error codes rather than data redundancy to correct bit errors. ODFM has very high spectral efficiency - close to the Shannon limit. Digital signals when encoded on ODFM allow closer spacing of sub-carriers than would analogue encoding.

OFCOM

Office of Communications. A UK regulatory body.

ONU

Optical Network Unit. This device converts optical fiber signals to electrical signals.

OTA

Over the Air [estimate]. This is the advertised speed of a wireless technology. For example, the 802.11a/g standard is advertised at 54Mb/s. This is only for ideal-conditions.

OUI

Organizationally Unique Identifier. The first three octets of a MAC address is unique to the manufacturer of the interface.

OSI

Open Systems Interconnect. Specifies seven separate layers used in communication stacks. Each layer has two interfaces. One interfaces to the layer below and the other to the layer above. The top layer interfaces with the machine which uses it. The bottom layer interfaces with the physical medium.

PAC

Protected Access Credential. This is a shared secret used by EAP-FAST. It creates a tunnel which is then used for authentication.

PAN

Personal Area Network - as created with bluetooth, Zigbee, RFID and so on. Short range - can interfere at 2.4GHz.

PBCC and PBCK

Packet Binary Convolution Coding (Keying). See CCK.

PC

Personal Computer.

PCF

Point Coordination Function. A not-widely-implemented means of sharing wireless air-time. DCF is more common. Compare with HCF.

PCI, PCIe

Peripheral Component Interconnect, an industry-standard bus for attaching peripherals to computers. 802.11 devices are available which use this interface. Usually PCI is an internal connector in a desktop machine. PCIe is a faster express version. There is a mini version for notebooks.

PCMCIA

Personal Computer Memory Card International Association. An interface card used in several ways - one of which is for wireless devices.

PDA

Personal Digital Assistant. Often wireless enabled.

PEAP

PEAP Cisco Microsoft and RSA created this as in open standard. It is similar in to EAP-TTLS and needs only a server-side PKI certificate to create a secure TLS tunnel to protect user authentication. As of May of 2005, there were two PEAP sub-types certified for the updated WPA and WPA2 standard. These are:
• PEAPv0/EAP-MSCHAPv2
• PEAPv1/EAP-GTC

PER

Packet Error Rate.

PHY

Not an acronym: Short for Physical. This is the lowest layer in the OSI model. It is the physical means of transmission, voltages, currents, methods of modulation and so on. It is split into two sublayers: PMD and PLCP.

PLCP

Physical Layer Convergence Protocol. This is an abstraction of the PMD from the Data Link Layer. See PHY.

PMD

Physical Medium Dependent sublayer of the PHY. This does the transmitting using some kind of modulation.

PN

Pseudorandom Number. A number from a deterministic sequence which has the same characteristics of a stream of random numbers except for the fact that the same stream is re-generated exactly given the same initial conditions.

PSDU

PLCP Service Data Unit.

POP3

Post Office Protocol Version 3 for receiving email where a POP connection results in email downloaded in entirety from the server. Contrast with IMAP.

POTS

Plain Old Telephone Service.

PRK

See BPSK.

PS

Power save (mode). A non-access point (AP) operates in active or power save mode where it is either awake of dozing. Some vendors call this "Power Save Poll" (PSP) mode. It's useful for battery operated devices but complicates frame delivery so it's not used for permanently powered stations.

PSK

Phase Shift Keying. This is a modulation method where the digits are encoded by altering the phase of the carrier. See also BPSK.

PtMP

Point to MultiPoint. A hub and spoke topology made from bridges would be a good example. See also PtP.

PtP

Peer to Peer / Point to Point. This describes a topology where one unit is directly connected to another via a wireless link or a wired link. Typically, a bridge is connected to another bridge to span several Km over a wireless link.

PMK

Pairwise master key. For each authenticated session there exists a Master Key (MK) between a station (STA) and an authentication Server (AS). From this MK, a PMK is created and is used between the STA and the AP.

POE

Power over Ethernet. This sends the voltage up the data cable so the device does not need a separate cable and power supply. It saves money, simplifies installation and provides a means to reboot the device remotely.

PPI

Per Packet Information. PPI is a general and extensible meta-information header format
originally developed to provide 802.11n radio information, but can handle other information as well. The intent is the information is only added to data captured in real-time, not stored packets.

PDSU

PLCP Service Data Unit. This is the actual data coming from the MAC layer.

PPDU

PLCP Protocol Data Unit. This is what is actually transmitted on the RF medium.

pre-RSNA

What was available before Robust Security Network Association. (i.e. WEP)

TPC

Transmit power control. Specified in 802.11h as a means to comply with certain regulations as in Europe, 802.11a can interfere with satellite transmissions. Devices must comply with ITU regulations in the 5GHz band. 802.11h uses DFS and TPC.

TSN

Transition Security Network. An insecure network where security associations (SA) are allowed in both RSNA (TKIP and CCMP) and pre-RSNA (WEP) form.

Q-S

ABC
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KLM
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QRS
TUV
WXYZ


QAM

Quadrature Amplitude Modulation. In the basic description, there are two carriers with the same frequency but differing in phase by 90 degrees. This allows two AM modulations into a single channel. In practice as in 16-QAM, four different phases and four different amplitudes are used for a total of 16 different symbols. See this simulation.

QAP

An Access Point (AP) with Quality Of Service (QoS) Capability.

QoS

Quality of Service.

RADIUS

Remote Authentication Dial In User Service which provides centralized Authentication, Authorization, and Accounting (AAA)

RC4

Rivest Cipher 4 - also known as ARC4 or ARCFOUR (Alleged RC4 since the algorithm is a leaked trade-secret from RSA). This is a widely-used software stream cipher. It is simple and fast but has serious cryptographic weaknesses when implemented incorrectly, and weaknesses in general that suggest it should not be used for new product.

RF

 

Radio Frequency.

RFC

Request for Comment. A series of notes about the Internet, started in 1969. Each is indexed by a numbers as in RFC as in one of the April 1st joke RFC2324

RFID

Radio Frequency IDentification. A small PAN tag with an antenna and CPU. These may have a battery for the CPU, be battery assisted when energy is drawn from RF, or no battery where CPU is powered by energy entirely from RF. Purpose: To respond to an RF query with a unique index for stock-take/security/logistics etc.

RSN

Robust Security Network. In a Beacon frame, this is indicated by the Information Element (IE).

RSNA

Robust Security Network Association. This is an algorithm. AES-CCMP must be supported. WEP and TKIP are optional. Part of 802.11i

RSSI

Received Signal Strength Indicator. This is a dimensionless integer within a vendor-specified range. It is a measure of the power in the signal at the receiver end. It is sometimes used in rough correlation to distance from the sender. Multiple RSSI readings from diverse points allow triangulation. A station may also note how RSSI drops and then roam to another stronger signal from another access point. Unless converted to percentage, the figures are only comparable within a specific vendor's products. See also RSSI_MAX.

 

RSSI_MAX

A vendor-specific value representing their own way of displaying RSSI where RSSI_MAX is an upper figure for the range.

Typical values:

 Vendor     RSSI_MAX
  Cisco     100
 Symbol     31
Atheros     60

Each of these have different levels of granularity - for example, Cisco discriminates 101 different power levels.

RTS

 

Request to send. This is a flow control operation.

SD

Secure Digital. This refers to an interface slot. There are 802.11 devices which use SD.

SDU

Service Data Unit.

SMB

Small to Medium Business.

SNMP

Simple Network Monitoring Protocol. A management tool which allows another computer to query its status, and allows the managed device to send alerts in the form of traps.

SNR

Signal to Noise Ratio. The signal must be stronger than the noise level. Bigger ratios are preferred.

SOM

System Operating Margin. This is the result of a link budget calculation. It is the amount of received signal strength relative to the client device's receive sensitivity.

SOM = Receive Sensitivity - Signal Strength.

SOHO

Small Office, Home Office. This refers to a class of network suitable for a few people typically working from home or in a small office.

SQL

Structured Query Language.

SSID

Service Set Identifier. Sent out with each packet, this essentially identifies the particular network name since all stations must use it to connect. See also ESSID.

SSH

Secure SHell. This allows a remote login or data transfer over an encrypted link. SSH can be used as a tunnel.

SSL

Secure Socket Layer - used by HTTPS.

STA

Station. This is any 802.11 device with access to the wireless medium.

T-V

ABC
DEF
GHIJ
KLM
NOP
QRS
TUV
WXYZ


TCP/IP

Transmission Control Protocol / Internet Protocol. This is a stateful connection oriented variable sized packet sent over the Internet Protocolthat is acknowledged by the receiver. The application using it is guaranteed to get error-corrected data at the possible expense of delays due to re-transmission.

 

TG

Task Group. Example: TGb is the 802.11b tack group.

TIM

Traffic Indication Map. When frames are buffered, the unit uses a TIM inside a beacon to inform STAs that there is buffered data. A TIM is a list of AIDs.

TKIP

Temporal Key Integrity Protocol. Replaces the flawed WEP encryption without the need to replace legacy hardware. It mixes a shared key with an initialization vector (IV) before seeding the RC4 encryption. In contrast, WEP only appended the IV to the shared secret. Providing an attacker cannot discover weak IVs, this technique effectively changes the encryption frequently which limits the amount of data that an attacker has for analysis.

TLS

Transport Layer Security. Used by HTTPS.

TLV

Type - Length - Value. This refers to a data structure used in management frames. The three fields specify "What, How long, and some DATA". As such is is a useful and flexible structure.

U-APSD

Unscheduled Automatic Power Save Delivery. a.k.a. WMM Power Save. 802.11e = QoS. U-PASD is needed for power saving in battery operated power-hungry QoS systems. QAPs must be used. U-PASD supports legacy TIM/DTIM/ATIM and triggered U-PASD modes.

USB

Universal Serial Bus. 802.11 devices are available for this computer interface.

UDP

 

User Datagram Protocol. This is a stateless connectionless small sized packet over the Internet Protocolthat is sent without expecting an acknowledgement. It is fast but the application using it needs to perform the error correction or otherwise cope with data loss.

 

UMTS

Universal Mobile Telecommunications System. A 3G technology.

UNII or U-NII

Unlicensed National Information Infrastructure. Divided into three bands:

GHz:

5.150   -   5.250      Lower   - Consumer / SOHO
5.250   -   5.350      Middle  - Consumer / SOHO
5.725   -   5.825      Upper

Each of these are divided into 4 non-overlapping channels.

Each channel has 53 sub-carriers. See OFDM.

 

UP

User Priority value. See also EDCA.

VoWLAN

 

Voice Over Wireless Local Area Network.

 

W-Z

ABC
DEF
GHIJ
KLM
NOP
QRS
TUV
WXYZ

W

Watt. A unit of power. Watts measure the rate of energy conversion. 1W = 1J/s where J is energy measured in Joules and s is seconds. RF propagation is typically a few Watts at source and is detectable down to 1000ths of a Watt - milliwatts (mW).

WE

Wireless extensions.

WECA [WiFi Alliance]

Wireless Ethernet Compatibility Alliance (WECA). Non profit certifying organization founded in 1999.

WEP

Wired Equivalence Protocol. An unsuccessful initial attempt to secure wireless connections to the same level as a wired network. See also WPA.

WiFi Alliance

See WECA

WiMAX

Worldwide Interoperability for Microwave Access. Broadband Wireless Access 802.16. 15-40 Mbps.

WIPS

Wireless Intrusion Prevention System.

WiMAX

Worldwide Interoperability for Microwave Access. This 10 Mbit/s technology is found in point-to-multipoint links and portable and fully mobile internet access.

WISP

Wireless Internet Service Provider. Often useful in rural environments.

WLAN

Wireless Local Area Network.

WM

Wireless Medium.

WMAN

Wireless Metropolitan Area Network. Covers a City or Suburb.

WMM

Wi-Fi Multimedia. Supports multimedia applications with Quality of Service (QoS) over Wireless media. The QoS priority levels are {voice, video, best effort, background}.

WMM power save

Wi-Fi Multimedia power save mode is optimized for latency sensitive applications like voice and other multimedia without sacrificing data rate when compared to legacy power save.

WNMS

Wireless Network Management System. This is used to monitor, update and manage autonomous access points or WLAN controllers that have lightweight APs.

VoFi

See wVoIP

VoWLAN

See wVoIP

VoWiFi

See wVoIP

WPA

Wi-Fi protected Access. A more secure method than Wired Equivalence Protocol (WEP).

WPA2

Wi-Fi protected Access 2. A more secure method than Wired Equivalence Protocol (WEP) with AES and CCMP and certified by the WiFi Alliance.

WPA-Enterprise , WPA-Enterprise2

Wi-Fi protected Access Wi-Fi protected Access 2. => for large installations. This uses EAP in a managed environment using IEEE 802.11X authentication framework. Via the Access point of a WLAN controller, the client and authentication server are mutually authenticated.

WPA-Personal , WPA2-Personal.

Wi-Fi protected Access. Where no authentication servers are available, a pre-shared key is used. If a good key is used than it is as secure as WPA-enterprise. However managing a large number of pre-shared keys is impractical.

WPS

Wi-Fi Protected Setup /Wi-Fi Simple Config. For home networks. WPS involves the use of EAP.

VSWR

Voltage Standing Wave Ratio. The ratio of impedance mismatch in an RF system. Quoted as X:1. (X to one). 1:1 is ideal and unattainable. 10:1 implies most power is lost due to mismatch. 6:1 is about 50% power loss.

wVoIP

Voice over Internet Protocol. See also VoWLAN voWiFi VoFi

Comments 2 comments

quicksand profile image

quicksand 6 years ago

Gee Whiz! A great reference hub! I am checking out some wi fi applications right now. Thanks. :)


computer networking abbreviations 6 years ago

Great list! Bookmarked. I could also suggest to use the following very extensive resource

http://www.all-acronyms.com/tag/computer_networkin...

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