Why do conference and school wireless networks always work so poorly? As IT professionals we are used to the network 'just working' and fixing things by changing configuration files. This mind-set, combined with obvious-but-wrong choices in laying out a wireless network frequently lead to a network that seems to work when it's tested, but that then becomes unusable when placed under load. This is at its worst at technical conferences where there are so many people, each carrying several devices, all trying to use the network at the same time, and in schools where you pack students close together and then try to have them all use their computers at the same time.

Is this a fundamental limitation of wireless? While it is true that there are some issues that cannot be solved, there are a lot of things that the network administrator can do to make the network work better. The key issue is the obvious, but under-appreciated fact that wireless networking is radio communications first. If your radio link doesn't work well, you have no chance of fixing it with your configuration and software. This paper is intended to give you an appreciation of what the issues are, and enough information to know what sorts of things to look out for when planning a high density wireless network.