IEEE 802.11 (legacy mode) or more correctly IEEE 802.11-1997 or IEEE 802.11-1999 refers to the original version of the

IEEE 802.11 IEEE 802.11 is part of the IEEE 802 set of local area network (LAN) technical standards, and specifies the set of medium access control (MAC) and physical layer (PHY) protocols for implementing wireless local area network (WLAN) computer com ...

wireless network A wireless network is a computer network that uses wireless data connections between network nodes. Wireless networking allows homes, telecommunications networks, and business installations to avoid the costly process of introducing cables int ...

ing standard released in 1997 and clarified in 1999. Most of the protocols described by this early version are rarely used today.

Description

It specified two raw

data rate Data rate and data transfer rate can refer to several related and overlapping concepts in communications networks: Achieved rate * Bit rate, the number of bits that are conveyed or processed per unit of time ** Data signaling rate or gross bit rate ...

s of 1 and 2

megabits per second In telecommunications, data transfer rate is the average number of bits (bitrate), characters or symbols ( baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are mul ...

(Mbit/s) to be transmitted via

infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...

(IR) signals or by either

frequency hopping Frequency-hopping spread spectrum (FHSS) is a method of transmitting radio signals by rapidly changing the carrier frequency among many frequencies occupying a large spectral band. The changes are controlled by a code known to both transmitter ...

direct-sequence spread spectrum In telecommunications, direct-sequence spread spectrum (DSSS) is a spread-spectrum modulation technique primarily used to reduce overall signal interference. The direct-sequence modulation makes the transmitted signal wider in bandwidth tha ...

(DSSS) in the Industrial Scientific Medical frequency band at 2.4 GHz. IR remained a part of the standard until IEEE 802.11-2016, but was never implemented. The original standard also defines carrier sense 0 access with collision avoidance (

CSMA/CA Carrier-sense multiple access with collision avoidance (CSMA/CA) in computer networking, is a link layer multiple access method in which carrier sensing is used. Under CSMA/CA, nodes attempt to avoid collisions by beginning transmission only af ...

) as the medium access method. A significant percentage of the available raw channel capacity is sacrificed (via the CSMA/CA mechanisms) in order to improve the reliability of data transmissions under diverse and adverse environmental conditions. IEEE 802.11-1999 also introduced the binary time unit TU defined as 1024 μs. At least seven different, somewhat-interoperable, commercial products appeared using the original specification, from companies like

Alvarion Alvarion Technologies Ltd. is a global provider of autonomous Wi-Fi networks designed with self-organizing capabilities for carrier-grade Wi-Fi, enterprise connectivity, smart city planning, smart hospitality, connected campuses, and connected e ...

(PRO.11 and BreezeAccess-II), BreezeCom, Digital / Cabletron (RoamAbout),

Lucent Lucent Technologies, Inc. was an American multinational telecommunications equipment company headquartered in Murray Hill, New Jersey. It was established on September 30, 1996, through the divestiture of the former AT&T Technologies busines ...

, Netwave Technologies (AirSurfer Plus and AirSurfer Pro),

Symbol Technologies Symbol Technologies, Inc., was an American manufacturer and supplier of mobile data capture and delivery equipment. The company specialized in barcode scanners, mobile computers, RFID systems and Wireless LAN infrastructure. In 2014, Symbol Tech ...

(Spectrum24), and Proxim Wireless (

OpenAir The core idea of artificial intelligence systems integration is making individual software components, such as speech synthesizers, interoperable with other components, such as Commonsense knowledge (artificial intelligence), common sense knowled ...

and

Rangelan2 The Wireless LAN Interoperability Forum (WLIF) was a non-profit industry organization founded in 1996 to promote and certify wireless LAN products. It was active from about 1996 through 1998 and disbanded in 2001. History The organization was anno ...

). A weakness of this original specification was that it offered so many choices that interoperability was sometimes challenging to realize. It is really more of a "beta specification" than a rigid specification, initially allowing individual product vendors the flexibility to differentiate their products but with little to no inter-vendor interoperability. The DSSS version of legacy 802.11 was rapidly supplemented (and popularized) by the

802.11b IEEE 802.11b-1999 or 802.11b is an amendment to the IEEE 802.11 wireless networking specification that extends throughout up to 11 Mbit/s using the same 2.4 GHz band. A related amendment was incorporated into the IEEE 802.11-2007 standard. ...

amendment in 1999, which increased the bit rate to 11 Mbit/s. Widespread adoption of 802.11 networks only occurred after the release of 802.11b which resulted in multiple interoperable products becoming available from multiple vendors. Consequently, comparatively few networks were implemented on the 802.11-1997 standard.

Description

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Further reading