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lunes, 22 de noviembre de 2010

802.11 Wireless Standard

Before setting up wireless network, you need to understand 802.11 wireless standard that can be used. 802.11a, 802.11b and 802.11g are three popular wireless communication standards. Wireless networks can be built using any of the three, but each has its advantages and disadvantages. 

802.11b

In September of 1999, the IEEE 802 committee extended the 802.11 standard, created 802.11b standard. It became popular due to low setup cost and bandwidth support up to 11Mbps in the 2.4GHz S-Band Industrial, Scientific, and Medical (ISM) frequency range. For your information, the maximum bandwidth supported by original 802.11 standard is only 2Mbps.

Being an unregulated frequency, 802.11b device can suffer interference from other wireless users, cordless phones, microwave ovens and other devices using the same 2.4 GHz band. However the interference can be avoided by placing 802.11b device a reasonable distance from other devices.

802.11a

802.11a was created the same time with 802.11b with the ability to support 55Mbps in the 5GHz band. 802.11a is not popular due to the slow availability of the 5 GHz components needed to implement products by vendor, more expensive cost and not compatible with 802.11b. The higher frequency also makes 802.11a signals have more difficulty to penetrate walls and other obstructions.

However the advantage of 802.11a is that it operates at a radio frequency that's less clogged by competing signals from other wireless users, cordless phones and microwave ovens. Its maximum bandwidth is higher as well comparing to 802.11b. 802.11a is usually found on business networks whereas 802.11b better suits the home network.

802.11g

Due to 802.11b is not compatible with 802.11a and there are needs for higher bandwidth, 802.11g was ratified in June 2003 to provide high data rate and maintain backward compatibility with 802.11b products.

802.11g supports bandwidth up to 55Mbps in the 2.4GHz band. 802.11g is compatible with 802.11b products because they both use the same radio frequency (2.4GHz) to transmit data over the airwaves, it means 802.11g wireless router will be able to talk to 80.11b wireless adapter. 802.11g also provides better security features, such as WiFi Protected Access (WAP) and WPA2 authentication with pre-shared key or RADIUS server.

Again, 802.11g also suffers from the same interference as 802.11b in the already crowded 2.4 GHz range, but can be avoided by placing 802.11g device a reasonable distance from other devices

802.11n

802.11n is latest wireless communication standard that was approved by IEEE in October 2009, and it can provide bandwidth up to 600Mbps, 10 times faster than 802.11g.

Prior to the release of this final approved 802.11n, several vendors already produced the wireless products based on 802.11n draft standard and they’re called 802.11pre-n or 802.11n(draft) wireless products, and it’s good to know that the 802.11n wireless product is backward compatible with those draft-n products.

Furthermore, 802.11n can operate in 2.4GHz or 5GHz band, and is backward compatible with 802.11a (5GHz band), 802.11b (2.4GHz band) and 802.11g (2.4GHz band) products.

If you want to set up a wireless network, you can use wireless products that support 802.11n standard that supports much higher bandwidth, but it’s more expensive if you compare to 802.11g products.

http://www.home-network-help.com/802-11.html

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