Wireless Network Administration: Understanding Wireless Standards
The most popular standards for wireless networks are the IEEE 802.11 standards. These standards are essential wireless Ethernet standards and use many of the same networking techniques that the cabled Ethernet standards (in other words, 802.3) use. Most notably, 802.11 networks use the same CSMA/CD technique as cabled Ethernet to recover from network collisions.
The 802.11 standards address the bottom two layers of the IEEE seven-layer model: The Physical layer and the Media Access Control (MAC) layer. Note that TCP/IP protocols apply to higher layers of the model. As a result, TCP/IP runs just fine on 802.11 networks.
The original 802.11 standard was adopted in 1997. Two additions to the standard, 802.11a and 802.11b, were adopted in 1999. The latest and greatest versions are 802.11g and 802.11n.
The basic characteristics of the four variants of 802.11 are summarized in the following table.
|Standard||Speeds||Frequency||Typical Range (Indoors)|
|802.11a||Up to 54 Mbps||5 GHz||150 feet|
|802.11b||Up to 11 Mbps||2.4 GHz||300 feet|
|802.11g||Up to 54 Mbps||2.4 GHz||300 feet|
|802.11n||Up to 600Mbps (but most devices are in the 100Mbps range)||2.4GHz||230 feet|
Currently, most wireless networks are based on the 802.11g standard. In 2009, the standard was upgraded to 802.11n, and 802.11n devices are now finding their way into many wireless networks.