Chapter 17: Mastering Dial-Up, Broadband, and On-the-Go Networking
The 802.11b specification was the first WiFi technology introduced to the market. It
uses the 2.4 GHz spectrum to transmit data at 11 Mbps. The 802.11b specification
uses Complimentary Code Keying (CCK) coding to transmit data. While 802.11b
has enjoyed the most widespread use, the lowering costs of faster technologies are
rapidly replacing it with newer technologies.
The 802.11a specification transmits in the 5 GHz spectrum at a transmission rate of
54 Mbps. This specification uses Orthogonal Frequency-Division Multiplexing
(OFDM) to transmit data, which is considerably better than the CCK coding stan-
dard. This gives 802.11a a considerably faster transmission rate.
The 802.11g specification transmits in the 2.4 GHz spectrum at a transmission rate
of 54 Mbps. This specification also uses OFDM to transmit data, and it enjoys the
most widespread use of the newer technologies.
These technologies fall under the WiFi designation, since they transmit in the 2.4
GHz and 5 GHz spectrums. Windows Vista supports each of these wireless technolo-
gies and the devices used to make connections to these types of networks.
New networking standards are also in the marketplace today. It bears noting that
early adoption of new technologies does not always favor the consumer, because
some products in the market may support early adoption of a standard that is not yet
finalized. Therefore, if you purchase products too early you may have to purchase
additional hardware to support the additional features defined in the final version of
the standard. While this is not always true, be wary of purchasing the latest and
greatest wireless products. Take some time to research the technology before buying
equipment on impulse.
Newer 802.11 transmission specifications include 802.11n, which offers up to 540
Mbps while using Multiple-Input-Multiple-Output (MIMO) technology. Essentially
this means that the client computer and the wireless access point will use multiple
receivers and multiple transmitters to achieve improved performance.
Not all 802.11 specifications are about transmission speed and rate, however. The
802.11i specification offers enhanced security. The 802.11h specification offers fre-
quency and power control management. The 802.11e specification offers quality of
service enhancements. The 802.11x specification provides a framework for authenti-
cating users and controlling their access to a protected network.
Another emerging wireless technology is Worldwide Interoperability for Microwave
Access (WiMax). WiMax is not really a technology, but a stamp of approval for use
with the 802.16 specification in broadband wireless deployments in metropolitan
areas. WiMax-certified equipment usually uses the 2.5 GHz spectrum, but the 3.5
GHz, 2.3 GHz, and 5 GHz spectrums are available in other countries. Currently, a
movement exists to use the 700 MHz spectrum for future WiMax deployments.