Wi-Fi Wireless Networking |
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What is Wi-FiWi-Fi is an abbreviation for Wireless Fidelity, Wi-Fi is used as a generic term to cover the 802.11 wireless communication standards.Wi-Fi Radio Frequency (RF) receivers on mobile (or fixed) devices enable users to connect to a remote network when they are in range of a Wireless Access Point (WAP). Areas where Wi-Fi can be received are known as hot spots. Wireless StandardsHistorically the 802.11b standard is the oldest and slowest standard. The standards that followed were 802.11a and the most recent 802.11g ratified in June 2003.Both 802.11a and g run at a capacity of 54 Mbit per second. The latest 802.11n is still under development.
108Mbit ps devices are not an agreed 802.11 standard. They can be less reliable than the 54Mbit ps standard. Its probably advisable to stick with a single supplier for all devices if you need this higher speed. Wireless Access Points (WAP's) are available for each networking standard and are often combined with other network products, like Routers, Switches & Modems. Multi standard WAP's are also available for two or more networking standards. Combined 802.11b/g products are the most common types of this form as they share the same 2.4 GHz band, but triple standard 802.11a/b/g WAP's are now also available transmitting on both 2.4 and 5 GHz bands. Wireless networks with devices using a mixture of two (or more) standards may have a degraded performance however. Maximum Capacity Fall BackIn difficult conditions or with distance the maximum wireless network capacity drops back to a lower setting to extend the range of the wireless network. Ranges may also vary with the power of the radio transmission and quality/positioning of aerials.Typical Indoor Ranges
Note that all range figures are estimates actual figures will vary!
These figures also reduce drastically with obstructions. |
Shared BroadbandDon't expect to much at a distance!With increased broadband speeds commonly available the 11b standard is not well suited for shared broadband access. At near to the maximum range even a single user will be unable to work at anything near full speed. 11g is more suitable but multiple users (online at the same time) and working at some distance from the WAP will also be unable to get the full speed. Wi-Fi Actual Transfer RatesYou will not get the data transfer rates quoted in the Maximum capacity figure. The actual figures (also known as throughput) are likely to be about 1/2 of this at best.WAP's with a large number of users connected or WAP's supporting multiple Wi-Fi standards are likely to have further reductions in the data transfer rates. Bits and Bytes (divide by 8)All network hubs and switches including wireless products are quoted in M bits not Mb (M bytes). As there are 8 bits per byte in the modern PC systems commonly used today. Divide the capacity by 8 to get the maximum capacity data transfer figure in Mb.So when download at 1Mbit ps, your best download speed would be something like 125Kb(bytes) ps.
Wi-Fi SecurityIn addition to all the usual network security issues Wi-Fi has the additional problem of mobile users accessing the networking. Two levels of security are available, both work by encrypting data, these are -
By default these are not turned on automatically! BluetoothBluetooth has a maximum capacity of 2M bit ps and uses the 2.45Ghz band, with limited support for TCP/IP it is also less suited for Network usage. Its more often used in PDA's & cell phones.External LinksWI-Fi News
by Peter Frost
Last Revised: 2nd January 2006 |