CHAPTER THREE
3 WIRELESS LAN STANDARDS
3.0 INTRODUCTION
Wireless technologies conform to a variety of standards and offer varying levels of security features. The principal advantages of standards are to encourage mass production and for interoperability of products from different vendors. For this paper, the discussion of wireless standards is limited to the IEEE 802.11 family.
3.1 THE IEEE 802.11 FAMILY OF STANDARDS
IEEE 802.11 is a family of standards for wireless local area network (WLAN) computer communication, first created in 1997 by the Institute of Electrical and Electronics Engineers (IEEE) LAN/MAN Standards Committee (IEEE 802) in the 5 GHz and 2.4 GHz public spectrum – Industrial, Scientific and Medical (ISM) - bands. The 802.11 specifications is the fundamental standard for WLAN. The standard defined the following functions and technologies WLAN architecture, MAC layer services such as association, re-association, authentication and privacy, frame formats, signalling functions, and WEP algorithm. It also defined what comprises a Basic Service Set (BSS)
– two or more fixed, portable, and/or moving nodes or stations communicating with each other over the air within a range, and specified two configuration modes ad hoc and infrastructure. The 802.11 was designed to support medium-range, higher data rate applications, such as Ethernet networks, and to address mobile and portable stations.
3.1.0 IEEE b
802.11 only supported a maximum network bandwidth of 2 Mbps - too slow for most applications. In July 1999, IEEE expanded on the original 802.11 standard creating the b specification. b supports bandwidth up to 11 Mbps, which is comparable to traditional Ethernet. It operates at the same 2.4 GHz unlicensed frequency band as the original 802.11 standard using direct sequence spread-spectrum (DSSS) technology.
Wireless Local Area Network (WLAN): Security Risk Assessment and Countermeasures Nwabude Arinze Sunday - 14 - 3.1.1 IEEE ab While b was in development, IEEE created a second extension to the original
802.11 standard called ab gained popularity much faster than a even, though they were created at almost the same time. bis more cost effective than a, as a result, a are commonly found on business networks whereas b serves the home market. a supports bandwidth up to 54 Mbps and operates in a licensed frequency spectrum around 5 GHz using orthogonal frequency division multiplexing (OFDM) technology to reduce interference. Comparatively, a covers a shorter range and has more difficulty penetrating walls and other obstacle as it operates at a higher frequency than b. The two technologies are incompatible with each other as they operate at different frequencies.
3.1.2 IEEE g
In 2003, the IEEE published g amendment. g attempts to combine the best of both a and b. g supports bandwidth up to 54 Mbps, and it operates at the 2.4 GHz frequency for greater range, using OFDM technologies. g is backwards compatible with b, by still supporting the complimentary code key
(CCK) modulation.
3.1.3 IEEE n
The newest IEEE 802.11 family of standards is n. It was designed to improve on gin the amount of bandwidth supported by utilizing multiple transmitter and receiver antennas – called multiple input, multiple output (MIMO) technology - instead of one. It is anticipated that n connections should support data rates of over 100
Mbps when finalized. With its increased signal intensity, n will offer somewhat better range over earlier 802.11 standards, and it will be backward compatible with g.
Share with your friends: |
