By the way, pretty much all of that missing throughput in Rule 1A is used to make sure all of your data gets from one place to another without any dropped bits. This overhead - which all communication protocols have - is heavier in wireless networking due to the tougher environment that data has to travel through.

As disappointing as losing half your throughput may be, you may never notice it in a small wireless network. It all depends on how many wireless clients you have, and what their data transfer requirements are. Here are a few scenarios for comparison.

Case 1: Probably won't notice

One to two wireless clients Occasional file and print sharing Network used mostly for Internet web browsing, email, instant messaging Internet connection via dialup

Explanation: These applications generally don't require high transfer rates for extended periods of time. Even if they did, the slow Internet connection is going to be the main factor in determining your effective client throughput.

Case 2: Might notice

Three to four wireless clients Occasional large Internet downloads Light local network file and print sharing One or two Internet audio streams One video stream

Explanation: With more wireless clients sharing the same relatively small bandwidth, the chances of more than one client wanting a large chunk of bandwidth at the same time are increased. Add the higher bandwidth requirements of audio and video streams and file and printer sharing, and your wireless users might occasionally notice some sluggishness on the network.

Note that I don't mention the Internet connection method as a wireless performance factor. Unless you live outside the United States where speeds in the 10's of Mbps are common, or are lucky enough to live in areas where Verizon is rolling out its FIOS optical fiber-based service, your broadband connection probably tops out at somewhere between 1.5 to 5 Mbps. This is well below the typical speeds found in wireless networks.

Case 3: Definitely will notice

More than four wireless clients Frequent large Internet file downloads Heavy local network file and print sharing activity More than one video stream More than two simultaneous audio streams

Explanation: More clients + larger data transfers = Frustrated users!

The other key factor that can affect the speed of your wireless network is enabling WEP encryption. WEP (Wired Equivalent Privacy) is a much maligned, but still useful, feature of 802.11 wireless gear that is intended to keep your wireless data private, and involves the use of an encryption algorithm. The encryption algorithm requires some fairly hefty number crunching, which some wireless adapters have trouble keeping up with. In some cases, enabling WEP encryption can cut your throughput by 50 to 60%. Note that while this problem has largely been eliminated in current 802.11g products, it can still be found in some products.

The most prefered solution is to use the more secure WPA (Wi-Fi Protected Access) or WPA-2 wireless security if your adapter supports them. But if your adapter doesn't, you should either enable WEP and take the throughput hit or buy a different adapter. No one should run an unsecured wireless network unless they intend to freely share their network resources and have properly secured clients and network shares from unauthorized access.