SmallNetBuilder

Introduction

Wireless networks are a wonderful thing. However, the freedom and convenience they provide can also come with a healthy dose of frustration and annoyance. Your pain might come in the form of frequent network disconnects, sluggish speed, inability to connect or, if you're really lucky, combinations of all three.

Fortunately, armed with a basic understanding of how wireless networks (also commonly known as wireless LANs or WLANs) work and some simple troubleshooting techniques, you can find, fix or at least minimize many WLAN problems.

In this first article of a series, I'll first provide an explanation of WLAN basics and then move on to describe common wireless problem symptoms and their probable causes. The goal is to help you choose the correct path toward solving the problem you actually have. This is important, since some "fixes" that are applied blindly can often make the actual problem worse!

WLAN Types

The two main types of wireless networks are Infrastructure, which are the most commonly encountered, and ad hoc.

In Infrastructure wireless networks, wireless clients (commonly referred to as Stations or STAs) connect to access points (APs), which coordinate and relay traffic among STAs. Note that in an Infrastructure WLAN, STAs do not directly communicate, which is a common misconception. APs also bridge data traffic between the wireless and wired segments of a LAN.

Note: A wireless router contains an access point (AP), router and switch combined to share a single Internet connection among wired and wireless clients. Wireless routers are normally used in small networks at homes and small businesses that require only a single AP. However, if additional wireless coverage is required, additional APs can be connected to the wireless router.

In this series, I'll usually use the term AP, but this can also mean wireless router.

Figure 1 illustrates the coordination and relaying functions in an Infrastructure WLAN. For a file transfer from Computer A to B, the data packets are transmitted from Computer A to the AP, then retransmitted to Computer B.

Figure 1: Sending and receiving on an infrastructure wireless network

In ad hoc wireless networks, STAs create a peer-to-peer network without an access point. The communication on a ad hoc network is regulated by protocols that are included in the 802.11 standards and implemented in each STA.

In this series, we'll concentrate on Infrastructure wireless networks since they are the predominant type.

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