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Introduction to IEEE 802.11 |
The evolution of the
wireless transport of data within a LAN environment has
led to the development of the IEEE 802.11 protocol - the
standard for high speed wireless LAN equipment.
The IEEE 802.11 specifications maintain a thorough set of
standards for operating wireless networks in the
license-free 2.4GHz spectrum. The power of the
network now combines with the freedom and mobility of
wireless connectivity to make IEEE 802.11 an indispensable
solution. Consequently, wireless networks are
emerging in many environments - business, education,
manufacturing, government and institutional.
The benefits of IEEE 802.11 are obvious:
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- mobility and
portability of IT devices
- no cabling or wiring
to connect to the LAN
- cost-effective over
short and long term
- time saving,
convenient and
easy implementation
- greater access to the
LAN
- roaming, ad-hoc and
secure connectivity
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What is IEEE 802.11? |
Developed by the Institute of Electrical and
Electronics Engineers in 1997, 802.11 refers to a family
of specifications for high speed wireless LAN technology. 802.11
specifies a wireless, through-the-air virtual connection
between a wireless client and a base station or between
two wireless clients.
IEEE 802 specifies the Ethernet protocol for LAN devices.
802.11 adds wireless connectivity while maintaining
Ethernet standards.
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- 802.11 provides 1 or 2 Mbps transmission in
the 2.4 GHz band using either frequency hopping spread
spectrum (FHSS) or direct sequence spread spectrum (DSSS).
- 802.11a is an extension to 802.11 that
applies to wireless LANs and provides up to 54 Mbps in
the 5GHz band. 802.11a uses an orthogonal frequency
division multiplexing encoding scheme rather than FHSS
or DSSS.
- 802.11b is an extension to 802.11 that
applies to wireless LANS and 802.11b+ provides 22 Mbps
transmission (with interoperability and backward
compatibility of 22, 11, 5.5, 2 and 1 Mbps) in the 2.4 GHz
band. 802.11b uses only DSSS. 802.11b was a 1999 IEEE
ratification supplemental to the original 802.11
standard, allowing throughput comparable to Ethernet.
- 802.11g -- applies to wireless LANs and
provides 54 Mbps transmission rates in the 2.4GHz
range.
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The de Facto
Standard |
The market has
currently adopted the 802.11 and 802.11b/b+ as the de facto
standard for wireless LAN devices. In fact, many
organizations have committed to earlier 802.11 products
running at 2 Mpbs. The technology is tried and true for
these clients.
The current standard is 802.11b which features a bandwidth of
11 Mpbs. 802.11b+ (a.k.a. 802.11b super & turbo
mode) pushes the
speed bar up to 44 Mbps.
Most importantly, these devices are all interoperable.
Backwards and cross compatibility is a chief benefit for
organizations that select 802.11b/b+ devices as 2, 11 and 22,
44 Mbps equipment can communicate with one another.
802.11a is being introduced as the next step up (going from
'b' to 'a' seems like going backwards, but that is the
timeline). However, 802.11a does not require devices to
be compatible
with previous 802.11b standards. Organizations with current
2-11-22 Mbps LAN devices may ignore the 802.11a standard.
Otherwise, running two separate LANs would be the result.
The standard for now and in the near future will continue to
be 802.11b/b+ due to their reliability, value and
compatibility.
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