Asus PCI-G31 - Manual (Page 32)

PCI-G31 WLAN Card User Manual
29 ASUS WLAN Card
ICS
ICS is used to share one computer’s Internet connection with the rest of the
computers on your network. When this computer is connected to the Internet, all
the communications to and from the Internet on your network are sent through this
computer which is called the host computer. The rest of the computers can send
and receive e-mail messages and access the web as if it were connected directly
to the Internet.
IEEE
The Institute of Electrical and Electronics Engineers. The IEEE sets standards
for networking, including Ethernet LANs. IEEE standards ensure interoperability
between systems of the same type.
IEEE 802.11
IEEE 802.xx is a set of specifications for LANs from the Institute of Electrical
and Electronic Engineers (IEEE). Most wired networks conform to 802.3, the
specification for CSMA/CD based Ethernet networks or 802.5, the specification for
token ring networks. 802.11 defines the standard for wireless LANs encompassing
three incompatible (non-interoperable) technologies: Frequency Hopping Spread
Spectrum (FHSS), Direct Sequence Spread Spectrum (DSSS), and Infrared. 802.11
specifies a carrier sense media access control and physical layer specifications for
1 and 2 Mbps wireless LANs.
IEEE 802.11a (54Mbits/sec)
Compared with 802.11b: The 802.11b standard was designed to operate in the
2.4GHz ISM (Industrial, Scientific and Medical) band using direct-sequence
spreadspectrum technology. The 802.11a standard, on the other hand, was
designed to operate in the more recently allocated 5-GHz UNII (Unlicensed
National Information Infrastructure) band. And unlike 802.11b, the 802.11a standard
departs from the traditional spread-spectrum technology, instead using a frequency
division multiplexing scheme that’s intended to be friendlier to office environments.
The 802.11a standard, which supports data rates of up to 54 Mbps, is the Fast
Ethernet analog to 802.11b, which supports data rates of up to 11 Mbps. Like
Ethernet and Fast Ethernet, 802.11b and 802.11a use an identical MAC (Media
Access Control). However, while Fast Ethernet uses the same physical-layer
encoding scheme as Ethernet (only faster), 802.11a uses an entirely different
encoding scheme, called OFDM (orthogonal frequency division multiplexing).
The 802.11b spectrum is plagued by saturation from wireless phones, microwave
ovens and other emerging wireless technologies, such as Bluetooth. In contrast,
802.11a spectrum is relatively free of interference.