WiFi or Wireless Fidelity - wireless networking

 

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Tutorial Overview

Topics covered in this tutorial (click link to jump to topic):

1. What is WiFi? 5. How is it better than Ethernet?
2. So what is a Hotspot? 6. WEP or WPA
3. Best used for... 7. Health Concerns
4. Disadvantages    

What is WiFi?

"WiFi" stands for "wireless fidelity". This is a marketing name and bares no relation particularly to the technology. WiFi networks use the 2.4 GHz radio spectrum to transmit data. For comparison's sake your mobile phone operates at around 800 Mhz and FM radio operates at up to 100 Mhz.

At the centre of a WiFi network is the WiFi router. Although routers come in many configurations, one of the most flexible arrangements is an adsl modem, ethernet router and WiFi base station all rolled into one device.

This gives you the fall back position of ethernet or the ability to plug in a non WiFi network printer. For security reasons you should ensure your WiFi router is capable of NAT, WPA and the ability to turn off SSID broadcasting. More about these terms later.

There are a number of standards in WiFi; a, b & g. G is the current standard. Many g devices are backwardly compatible with b devices. WiFi is a global standard and now there are many manufacturers of WiFi products; thus the price has come down in recent years.

Different countries have different regulator regimes surrounding WiFi. In the US there is less regulation than in Australia. See the "Other resources" section below for links to Australian Government info on wifi networks.

So what is a Hotspot?

The term "hotspot" refers to the epicentre of the WiFi network. It is an unseen space where the wifi signal reaches around the wifi router. So a hotspot can be the router (when indoors) or the outdoor antenna connected to the router.

There are three lead manufacturers in wifi products: Netgear, Dlink and Linksys. The equipment you choose will be determined part by your budget and part by the functions you require.

Most routers use a browser based interface to allow you access to the router's firmware. The router generally takes the 192.168.0.1 address on a network (i.e. the first address) and then goes about distributing IP addresses to other computers and devices on it's network. Some routers use the 10.0.0.1 range.

Today most routers are NAT enabled. NAT stands for "natural address translation". NAT hides the IPs of other devices on your network from the outside world, greatly increasing your network's security.

Routers vary greatly in there capabilities. For example, low end routers aimed at the home user market will not come equipped with network monitoring built in, even with the router's operating software is Linux based.

Best used For...

WiFi networks are deployed in the following situations:

  • temporary offices where the tenants expect to move
  • where the cost of ethernet cabling is prohibitive, say between large buildings in an industrial estate or in a single level hotel complex
  • Internet cafes where people bring their own laptops along e.g. Starbucks
  • neighbourhoods where neighbours want to share Internet access and music files
  • where a person needs to be mobile (say with a palm device or laptop) within a nework e.g a foreman in a large wharehouse

Disadvantages

  • WiFi has to be "line of sight" between the two connected devices. This rule can be bent but it is easily broken. Trees can particularly get in the way.
  • a WiFi network's broadcast range is quite low, e.g. 90m with a low gain outdoor antenna
  • heavy rain can effect network performance
  • security is often not deployed or inadequately delpoyed
  • WiFi equipment shares the same spectrum as household microwave ovens, cordless phones, barcode readers, movement detectors, radio location devices, video surveillance, other industrial scientific and medical devices.

How is it better than Ethernet?

WiFi is better simply because no cabling is required making it a cheaper and faster network to roll out.

The current "G" standards only transmits data at 57mbps compared to an ethernet's 100mbps. So no advantage there. However if the primary purpose of the network is to share broadband Internet access and the maximum connection speed available is only 1.5mbps, then the Internet connection speed will be noticed before the network speed.

Conversely, if the primary purpose of the network is to share large files, then network speed is very important. The next wireless standard, "I", will move WiFi's speed to 110 mbps.

WEP or WPA - wireless security features

WEP and WPA are encryption protocols that you can choose from in your router's firmware. Quite simply, WEP is broken and WPA is the go. Wi-Fi Protected Access (WPA), a subset of the upcoming 802.11i security standard, will replace the flawed Wired Equivalent Privacy (WEP).

Depending on your circumstances you may decide to hide your SSID - service set identifier. You can think of the SSID as your network name, similiar to a windows workgroup. Without your SSID, people will not be able to join your wifi hotspot.

Health Concerns

According to the Wi-Fi Alliance industry group there is no evidence suggesting that wireless LANs are dangerous. Commentators point out many other devices, including mobile phones, use radio waves of similar strength and these devices are held much closer to your body. Manufacturers warn you not to sit within 30cm of outdoor antennas.

Other Resources

http://en.wikipedia.org/wiki/Wifi
http://www.acma.gov.au/ACMAINTER.65646:::pc=PC_1739
http://www.acma.gov.au/ACMAINTER.65640:STANDARD:1762238508:pc=PC_1778
Wired Magazine's Wifi Articles
How Stuff Works Wifi Article
Free WiFi in Australia

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