What is a wireless link?

It connects separate local area networks (LANs) usually in different buildings. Each link connects in one of two ways: 'point to point' - which connects two LANs, or 'point to multi-point' - which connects one LAN to multiple others. The frequencies wireless links work at can be selected from a number of ranges. Some frequencies require a license to be purchased, but they should suffer less from interference than the unlicensed frequencies.

Why use a wireless link?

Although they have an initial setup cost, a wireless link is relatively cheap to run and so can be cheaper over the mid and long term than a leased line between buildings. Each wireless link is independent of others and leased lines, so they can increase the overall capacity and reliability of connections between LANs. They can also enable separate buildings to share their Internet connections and other resources.

What is the range of a wireless link?

The range of a wireless link depends on a number of factors including characteristics of the equipment, transmission power, frequencies used, physical obstacles, weather conditions, and interference from other transmitters. Typically wireless links span distances from just a few metres up to 10km but more advanced links can have a range of well over 100km. Physical obstacles can make a very big difference to range, particularly metal and dense vegetation such as trees. As water absorbs radio waves so rain reduces range. Consequently wet trees will strongly reduce range even after rain stops.

How can a wireless link be implemented?

A wireless link has radio devices that exchange data; one is connected to each different LAN. These radio devices often use a specialised form of WiFi to communicate, but do not exchange data directly with WiFi clients. Alternatives to a wireless link exist, but they generally have important limitations.