802.11g defines the u se of the same OFDM modulation technique specified in IEEE
802.11a for the 5 GHz f requency band and applie s it in the same 2.4 GHz frequency
band as IEEE 80 2.11b. The 802.11g standard requires ba ckward compatibility with
802.11b.
The standard specifically calls for:
A. A new phy sical layer for the 802.11 Medium A ccess Control (MAC) in the 2.4 G Hz
frequency band, known a s the extended rate PHY (E RP ). The E RP add s OFDM as
a mandatory new coding scheme for 6, 12 and 24 Mbp s (mandatory speeds), and
18, 36, 48 and 54 M bp s (optional speeds). The ERP include s the modulation
schemes found in 802.11b including CCK for 11 and 5.5 M bp s and Barker code
modulation for 2 and 1 M bp s.
B. A pro tec ti on m echani sm called RTS/CTS that govern s ho w 802.11g devices and
802.11b devices inte roperate.
2. What is t he I EEE 802.11b s tandard？
The IEEE 802.11b Wirele ss LAN standard subcommittee, which formulate s the
standard for the indu st ry. The objective is to enable wi reless LAN hardware from
different manufactures to communicate.
3. What does IEEE 8 02.11 feature s upport？
The product suppo rts the fol l owing IEEE 802.11 fun ction s:
z CSMA/CA plus Acknowledge Protocol
z Multi-Channel Roaming
z Automatic Rate Selecti on
z RTS/CT S Fea ture
z Fragmentation
z Power Management
4. What is Ad-hoc？
An Ad-hoc integrated wirel ess LAN is a group of computer s, e ach ha s a Wireless LAN
adapter, Connected as an independ ent wireless LAN. Ad hoc wireless LAN is
applicable at a depar tmental scale for a branch o r SOHO ope ration.
5. What is Infrastructure？
An integrated wi rele ss and wireless and wired LAN i s called an Infrastructure
configuration. Infra structure i s applicable to enterprise scale fo r wirel ess access to
central database, or wi reless application for mobile worke r s.
6. What is BSS ID？
A specific Ad hoc LAN i s called a Basic Service Set (BSS). Computers in a BSS mu st
be configured with the same BSS ID.
7. What is WEP？
WEP is Wired Equival ent P rivacy, a data privacy mechani sm based on a 40 bit shared
key algorithm, a s described in the IEEE 802 .11 standard.
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