As opposed to Bluetooth and 3G, which may become widely used in the future, 802.11 has already been used extensively and successfully in numerous wireless LANs (WLAN). Linux support for this protocol will probably become an integral part of the standard kernel. 

A Bit of History
The first 802.11 standard was approved in 1997. It featured frequency hopping (which we will discuss momentarily) on a 2.4 Ghz band and two data transfer speeds: 1 Mbps and 2 Mbps. The 802.11a standard, which was released less than a year ago, added more features, including a higher data transfer speed and a 5 GHz band. The success of 802.11 can be attributed to several factors. First, it is based on the mature and proven infrastructure of the Ethernet protocol. Secondly, the cellular revolution has served as a model for computer users to look up to. Finally, the 802.11 seems to be the most cost-effective solution for wireless networking at present. Thus, setting up a basic wireless LAN (WLAN) would cost you only a few hundred dollars.

Under The Hood
Frequency hopping is the heart of any wireless and mobile network. A frequency hopping system jumps automatically, in a user-transparent manner, from one frequency to another, in a random fashion. A frequency hop occurs when a user moves towards the end of the current frequency's range or when for some reason, the current channel is unavailable (it's similar to the way you switch to a different channel on a cordless phone when the current channel becomes noisy).

Challenges of Wireless Networking
As opposed to wired networks, the likelihood of data corruption and interference from external sources in a wireless network is much higher. For this reason, 802.11 uses the "positive acknowledgment" protocol, whereby all transmitted frames must be acknowledged. If no acknowledgment is received within a certain time frame, the transmitter assumes that the packet was lost and must be re-sent. Security is another problem since eavesdropping is much easier. Furthermore, authenticating a client that isn't physically connected to the network isn't a trivial task. While there are solutions to these problems, they aren't bulletproof. Future revisions of the 802.11 standard will offer tighter security.

802.11 on Linux
Wireless hardware for Linux is available from various manufacturers. Installing a wireless card on Linux creates Ethernet interfaces. Applications that use these interfaces aren't radically different from wired Ethernet applications. For instance, ARP and IP configuration work identically the same. Next week, I will discuss the installation process on Linux in further detail and list some of the available 802.11 chipsets for Linux.