Corporate or campus wireless networks avoid all of the individual computer cable runs by establishing a central radio facility that is connected to the servers' network. Each computer has a wireless network card that communicates over a wireless frequency with the central radio facility. This architecture is depicted in Figure 2 . Communication rates vary from system to system, but typical rates range anywhere from 1 Mbps to 11 Mbps. The newer systems are using the 11 Mbps, and some manufacturers are starting to talk about rates as high as 20 Mbps in the future.
Wireless interfaces are available for desktop as well as notebook computers.
Notebook computers are mobile, of course, but must still be within a few miles of the central radio to maintain network connection. Radio bands for wireless networking are typically 2.4 GHz, but some systems use 900 MHz or 5.8 GHz. There are a few cautions I would note. All wireless users share the radio circuit, so it reacts like a single LAN segment. That means too many users will result in high collisions and slow network response.