What is wireless networking?

Technically, wireless networking refers to any data exchange between PCs and other devices which doesn't involve cables. Connecting to a wireless hotspot in a cafe, sending data from your PC to a handheld computer using an infrared link, or synching data between your mobile phone and notebook via Bluetooth are all examples of wireless networking.

In practice, however, wireless networking allows computers and peripherals to communicate using radio frequency (RF) transmissions rather than over conventional network cabling. Using wireless Ethernet adaptors, any device capable of being used on a regular computer network can be accessed over a wireless connection for tasks ranging from file and printer sharing to multimedia and Internet access.

Wireless Ethernet technology is generally outlined by a set of standards called IEEE 802.11, although other wireless technologies and protocols such as HomeRF and Bluetooth also exist. A wireless network of this kind can offer you all the facilities of a conventional PC network, such as Internet access and the ability to share files and peripherals such as printers. It uses the same Ethernet standards for transmitting data, but doesn't require every machine be connected by cable to a network hub. In the previous examples, connecting in a cafe makes use of Wi-Fi wireless networks, while the others don't.

This guide will focus on wireless networking at home or in a small business, using equipment based on the 802.11 standard.

What is Wi-Fi?

Wi-Fi is a certification program established by the Wi-Fi Alliance (www.wirelessethernet.org) to ensure the interoperability of wireless devices. Originally, the term Wi-Fi was intended to be interchangeable with 802.11b, but more recently it has broadened to cover any 802.11 network. Bear in mind that while all Wi-Fi devices conform to the IEEE 802.11 standard, the reverse is not always true.

Wireless standards

The communication protocols for wireless networking are defined by the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, which incorporates the 802.11a, 802.11b and 802.11g protocols (although several other standards are in progress). The most widely used of these is 802.11b (Wireless-B), which is more reliable than the faster 802.11a (Wireless-A) standard. It is more cost-effective to produce and operate as well. Wireless-G, or 802.11g, is a newer protocol that is becoming more widely adopted by vendors as it is capable of speeds up to 54Mbps rather than the 11Mbps of 802.11b devices.

It is very rare to find devices that support all three standards, but Wireless-G is designed to be backwards compatible with Wireless-B devices. Thus Wireless-B and Wireless-A devices will not work with each other, and neither are they compatible with Wireless-G devices.

It is worth noting that although the maximum speed provided by the IEEE standards is 54Mbps, some vendors (notably D-Link) have introduced proprietary protocols that effectively double the 802.11b rate to 22Mbps and the 802.11g rate to 108Mbps. Once again this is a theoretical throughput, with actual data rates being considerably lower. It is also worth bearing in mind that all wireless network devices must support the proprietary standard in order to function at these higher speeds.

How does wireless work?

Wireless technology utilizes the license-free radio frequency bands around the 2.4GHz and/or 5GHz ranges. The 802.11b and 802.11g protocols use the 2.4GHz band whereas 802.11a uses the 5GHz band. The benefit of this frequency band is that it is longer-range, although it can be susceptible to interference from other RF devices such as cordless phones.

The 5GHz band used by 802.11a provides more bandwidth and less interference, but it requires more expensive hardware, larger silicon chips and higher power consumption. As a consequence, Wireless-B is by far the most popular standard, with the newer Wireless-G closing in fast.