Get Unwired with WiFi
30-20-2003
By: Shane Dempsey
Most people who use wired networks in work or even at home are familiar with the hassles and limitations of connecting computers using Ethernet cables. These include the difficulty and cost of installing cables and restriction of movement. So wouldn't it be nice to be freed from those wires?
WiFi is an excellent alternative in many situations, but what is WiFi?. This is the trademark for the Institute of Electrical and Electronic Engineers' (IEEE's) 802.11 set of wireless networking standards. These standards specify the technology required to create computer networks using Ultra High Frequency (UHF) radio communications.
Basically how it works is that using a WiFi card, which acts as a transceiver installed on their PC or laptop, users can communicate using radio frequencies with wireless access points (sometimes called wireless hubs). For example, hardware compatible with the 802.11b standard communicates in the unlicensed 2.4 GHz radio frequency band. This is the same frequency as Microwave ovens but, understandably, 802.11b transmits at a much lower power ranging from 50 to100 milliwatts. The range is limited to about 150 metres with line-of-sight between transmitter and receiver but with different power and antenna configurations the range can be considerably extended. Areas within the range of a wireless card and hub are called 'hotspots'.
The 802.11b specification claims 11 Mbps(megabytes per second) transmission rates although half this rate is achieved in practice. These speeds are comparable with a slower specification Ethernet Local Area Network (LAN) with two busy users competing for network resources. It is worth remembering that transmission rates decrease with signal strength and hence distance.
The transmission rates compare very favourably indeed with the 56Kbps (kilobits per second) dial up services that most Irish Internet users connect with. The 802.11a standard however, provides almost 5 times (54 Mbps) the bit rate of 802.11b using the 5 GHz frequency band. And the latest standard, 802.11g should double the data-rate using the same operating frequencies as 802.11a.
WiFi equipment is relatively inexpensive. WiFi cards cost under EUR100 and wireless access points start at around EUR300. A home or office network can be created quite cheaply and quickly.
WiFi's worldwide popularity is growing as enthusiasts and corporations recognise its usefulness in delivering high-speed wireless access to workers, customers and friends. For example the Starbucks coffee chain is rolling out WiFi access for customers across its 4,000 North American cafes [1].
WiFi data is sent over the air and this means that data and network resources need to be protected from computer hackers. WiFi specifies Wireless Equivalent Privacy (WEP) for data encryption. WEP is flawed however [2] and alternatives such as creating Virtual Private Networks [3] between wireless devices are often preferable.
[1] nwfusion.com
[2] isaac.cs.berkeley.edu/isaac/
[3] www.intranetjournal.com/
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