Definition

Wi-Fi (802.11x standard)

Contributor(s): David Morris, Jack Hanlin, Derek Walker, Lisa Phifer

Wi-Fi is a term for certain types of wireless local area networks (WLAN) that use specifications in the 802.11 family -- for example,  Wi-Fi Direct, a peer-to-peer specification that allows devices certified for Wi-Fi Direct to exchange data without an internet connection or a wireless router. Products that pass Wi-Fi Alliance tests for interoperability, security and application-specific protocols are labeled "Wi-Fi CERTIFIED," a registered trademark of the Alliance.

How does Wi-Fi work?

A Wi-Fi network uses radio waves to wirelessly transmit information across a LAN, the reach of which can be extended by a Wi-Fi range extender. A computer utilizes a wireless adapter to translate data transmitted by radio waves. These waves are different from those emitted by, for example, FM radios, for which frequency is measured in megahertz (MHz). Wi-Fi's signals are transmitted in frequencies of between 2.5 and 5 gigahertz (GHz). This signal is then transmitted from the adapter through a router, after which it is sent to the internet.

What are hotspots?

Wi-Fi is widely used in businesses, agencies, schools and homes as an alternative to a wired LAN. Many airports, hotels and fast-food facilities offer public access to Wi-Fi networks. These locations are known as hotspots. Many charge a daily or hourly rate for access, but some are free. An interconnected area of hotspots and network access points is known as a hot zone.

Modern smartphones and tablets are also able to turn into Wi-Fi hotspots, using their cellular network connections to provide wireless internet connectivity to computers and other devices.

To access Wi-Fi hotspots, computers should include wireless adapters. These can be found on laptops and mobile devices, such as tablets or mobile phones. If for some reason your computer doesn't include such an adapter, one can be purchased that can be inserted into the PCI slot or USB port. Your computer should then be able to locate Wi-Fi networks automatically in the area. These can either be open networks or protected networks; the latter can be joined by entering a Wi-Fi password.

Unless adequately protected, a Wi-Fi network can be susceptible to access by unauthorized users who use the access as a free internet connection. The activity of locating and exploiting security-exposed wireless LANs is called war driving. An identifying iconography, called war chalking, has evolved. Any entity that has a wireless LAN should use security safeguards, such as the Wired Equivalent Privacy, or WEP, encryption standard; the more recent Wi-Fi Protected Access, or WPA; Internet Protocol Security, or IPsec; or a virtual private network, or VPN

The term Wi-Fi was created by the Wi-Fi Alliance as a play on Hi-Fi, an abbreviation for high fidelity, which referred to high-quality audio reproduction. Similarly, Wi-Fi is often thought to be short for wireless fidelity. However, according to the Wi-Fi Alliance, Wi-Fi is not an abbreviation. The confusion may stem from the fact that the Alliance briefly used, "The standard for wireless fidelity," as a slogan for Wi-Fi. 

Originally, Wi-Fi certification was applicable only to products using the 802.11b standard. Today, Wi-Fi can apply to products that use any 802.11 standard. The 802.11 specifications are part of an evolving set of wireless network standards known as the 802.11 family. The particular specification under which a Wi-Fi network operates is called the "flavor" of the network.

802

Overview

Basics of physical and logical networking concepts

802.1

Bridging

LAN/MAN bridging and management. Covers management and the lower sublayers of OSI Layer 2, including MAC-based bridging (Media Access Control), virtual LANs and port-based access control.

802.2

Logical Link

Commonly referred to as the LLC, or Logical Link Control specification. The LLC is the top sublayer in the data-link layer, OSI Layer 2. Interfaces with the network Layer 3.

802.3

Ethernet

"Granddaddy" of the 802 specifications. Provides asynchronous networking using "carrier sense, multiple access with collision detect" (CSMA/CD) over coax, twisted-pair copper and fiber media. Current speeds range from 10 Mbps to 10 Gbps. Click for a list of the hot 802.3 technologies.

802.4

Token bus

Disbanded

802.5

Token ring

The original token-passing standard for twisted-pair, shielded copper cables. Supports copper and fiber cabling from 4 Mbps to 100 Mbps. Often called "IBM Token-Ring."

802.6

Distributed queue dual bus (DQDB)

"Superseded **Revision of 802.1D-1990 edition (ISO/IEC 10038). 802.1D incorporates P802.1p and P802.12e. It also incorporates and supersedes published standards 802.1j and 802.6k. Superseded by 802.1D-2004." (See IEEE status page.)

802.7

Broadband LAN practices

Withdrawn standard. Withdrawn date: Feb. 7, 2003. No longer endorsed by the IEEE. (See IEEE status page.)

802.8

Fiber optic practices

Withdrawn PAR. Standards project no longer endorsed by the IEEE. (See IEEE status page.)

802.9

Integrated services LAN

Withdrawn PAR. Standards project no longer endorsed by the IEEE. (See IEEE status page.)

802.10

Interoperable LAN security

Superseded **Contains: IEEE Standard 802.10b-1992. (See IEEE status page.)

802.11

 Wi-Fi

Wireless LAN Media Access Control and Physical Layer specification. 802.11a,b,g,etc. are amendments to the original 802.11 standard. Products that implement 802.11 standards must pass tests and are referred to as "Wi-Fi-certified."

802.11a

 

  • Specifies a PHY that operates in the 5 GHz U-NII band in the U.S. -- initially 5.15-5.35 and 5.725-5.85 -- since expanded to additional frequencies;
  • Uses Orthogonal Frequency-Division Multiplexing;
  • Enhanced data speed to 54 Mbps; and
  • Ratified after 802.11b.

802.11b

 

  • Enhancement to 802.11 that added higher data rate modes to the DSSS (Direct Sequence Spread Spectrum) already defined in the original 802.11 standard;
  • Boosted data speed to 11 Mbps;
  • 22 MHz bandwidth yields three nonoverlapping channels in the frequency range of 2.400 GHz to 2.4835 GHz; and
  • Beacons at 1 Mbps, falls back to 5.5, 2 or 1 Mbps from 11 Mbps max.

802.11d

 

  • Enhancement to 802.11a and 802.11b that allows for global roaming; and
  • Particulars can be set at Media Access Control layer.

802.11e

 

  • Enhancement to 802.11 that includes quality-of-service features; and
  • Facilitates prioritization of data, voice and video transmissions.

802.11g

 

  • Extends the maximum data rate of WLAN devices that operate in the 2.4 GHz band, in a fashion that permits interoperation with 802.11b devices;
  • Uses OFDM Modulation (Orthogonal FDM); and
  • Operates at up to 54 (Mbps, with fallback speeds that include the "b" speeds.

802.11h

 

  • Enhancement to 802.11a that resolves interference issues;
  • Dynamic frequency selection; and
  • Transmit power control.

802.11i

 

  • Enhancement to 802.11 that offers additional security for WLAN applications; and
  • Defines more robust encryption, authentication and key exchange, as well as options for key caching and preauthentication.

802.11j

 

  • Japanese regulatory extensions to 802.11a specification; and
  • Frequency range of 4.9 GHz to 5.0 GHz.

802.11k

 

  • Radio resource measurements for networks using 802.11 family specifications

802.11m

 

  • Maintenance of 802.11 family specifications; and
  • Corrections and amendments to existing documentation.

802.11n

 

  • Higher-speed standards;
  • Several competing and noncompatible technologies -- often called "pre-n";
  • Top speeds claimed of 108, 240, and 350+ MHz; and
  • Competing proposals come from the groups, EWC, TGn Sync and WWiSE, and are all variations based on MIMO (multiple input, multiple output).

802.11x

 

  • Misused generic term for 802.11 family specifications

802.12

Demand priority

Increases Ethernet data rate to 100 Mbps by controlling media utilization.

802.13

Not used

Not used

802.14

Cable modems

Withdrawn PAR. Standards project no longer endorsed by the IEEE.

 802.15

Wireless personal area networks

Communications specification that was approved in early 2002 by the IEEE for wireless personal area networks, or WPANs.

802.15.1

Bluetooth

Short range (10m) wireless technology for cordless mouse, keyboard and hands-free headset at 2.4 GHz.

802.15.3a

UWB

Short-range, high-bandwidth ultra wideband link

802.15.4

ZigBee

Short-range wireless sensor networks

802.15.5

Mesh network

  • Extension of network coverage without increasing the transmit power or the receiver sensitivity;
  • Enhanced reliability via route redundancy; and
  • Easier network configuration and better device battery life.

802.16

Wireless metropolitan area networks

This family of standards covers Fixed and Mobile Broadband Wireless Access methods used to create wireless metropolitan area networks. Connects base stations to the internet using OFDM in unlicensed (900 MHz, 2.4, 5.8 GHz) or licensed (700 MHz, 2.5-3.6 GHz) frequency bands. Products that implement 802.16 standards can undergo WiMAX certification testing.

802.17

Resilient Packet Ring

IEEE working group description

802.18

Radio Regulatory TAG

IEEE 802.18 standards committee

802.19

Coexistence

IEEE 802.19 Coexistence Technical Advisory Group

802.20

Mobile Broadband Wireless Access

IEEE 802.20 mission and project scope

802.21

Media Independent Handoff

IEEE 802.21 mission and project scope

802.22

Wireless regional area network

IEEE 802.22 mission and project scope

This was last updated in January 2017

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Have you had experience with unauthorized users gaining access to your Wi-Fi connection? If so, what were they?
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That's an amazing list of specifications. Well, as they say, the wonderful thing about standards is that we have so many of them.
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