Explaing Wirless Networking
Posted 18 October 2005 - 12:55 AM
Posted 18 October 2005 - 03:48 PM
Posted 18 October 2005 - 04:45 PM
Posted 18 October 2005 - 09:04 PM
If it's just the basics you need here is a A little copy and Paste from my online class... If you want the whole thing send me your e-mail address in a PM and I'll copy paste the class and send it to you (I hope that isn't a violation of TOS - Not sure)...
Wireless networking connects two or more computers via radio signals, allowing shared files /
resouces, printers, or Internet access.
How it works
Each PC in a wireless network is equipped with a radio transceiver, often called a wireless
LAN adapter or Wireless NIC, that sends and receives RADIO SIGNALS to and from other
PCs on the network.
Breakdown of Radio Signals
The RADIO SIGNALS are data that is sent in packets. Each adapter (or radio Transceiver)
has a permanent, unique ID number that serves as an address, and each DATA PACKET
contains the data as well as the address of the recipient and that of sender.
Traffic control of Data Packets
A wireless LAN card (Transceiver) checks for an opening before sending a packet out to the
network. When it detects a pause, it sends the packet. If it senses other data on the radio
frequency, it waits for a moment and then checks again.
Basic Network Types
Wireless LANs commonly use one of two topologies, or ways to organize the network: 1) In an
AD-HOC topology - Each PC equipped with a wireless adapter broadcasts and receives data to
and from all other transceiver-equipped PCs within about 300 feet. 2) In an
INFRASTRUCTURE topology, each PC sends data to and receives data, from an access point,
which is mounted on a wall or ceiling and usually looks like a small box with an extended
antenna. When the access point receives data, it can resend the data (with greater range) over
radio frequencies to PCs in its coverage area, or it can transfer the data to a wired Ethernet
network. Access points can be added in an infrastructure network to offer greater range.
Basics of Speed and Security
While all wireless LANs work on these common principles, the speed at which they transmit
data and the frequencies they use differ, depending on which standard they follow. Vendors
may use any of several wireless standards, including IEEE 802.11, IEEE 802.11b, IEEE
802.11g, OpenAir, and HomeRF. Unfortunately, these standards don't always work with one
another, and all the adapters on your network must adhere to the same standard. All the
standards call for adapters to use a small segment of the 2.4-GHz radio band, leaving them
with little radio bandwidth for sending data. But adapters use one of two signaling protocols
to increase efficiency and security: 1) Frequency hopping spread spectrum method - rapidly
sends part of each data packet across several adjacent radio frequencies, one right after the
other, until the entire message has been sent. The speed at which these hopping signals change
frequency provides a measure of security, because most radios can't follow them. 2)The
direct sequence spread spectrum method - divides the radio band into three equal parts and
spreads the entire packet across one of those sections. Direct sequence adapters encrypt and
decrypt data, so unintended recipients using a radio to pick up the signal would hear only
Wireless LAN vendors usually state the maximum transfer rate of their adapters. Models that
adhere to the 802.11 standard transfer data at 2 megabits per second, using either the
frequency hopping or direct sequence method. Adapters that use the OpenAir standard
transfer data at 1.6 mbps using frequency hopping. And a new standard, HomeRF, can send
both voice and data (using frequency hopping) at 1.6 mbps. The fastest wireless LANs use the
IEEE 802.11b High-Rate standard, also called WiFi, to move data at a maximum speed of
about 11 mbps using the direct sequence protocol.
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