Summary

WLAN technologies have replaced Layer 1 physical wiring and Layer 2 transport technologies with wireless. One advantage of this replacement is that upper-layer protocols, like IP/TCP/UDP, are not usually affected. The wireless issues most often encountered include signal interference or obstruction, which are not commonly found in wired environments.

There are different antenna types that can be used with access points:

• Omnidirectional antennas
• Directional antennas
• Yagi antennas
• Parabolic antennas

When planning to install a new access point (AP), there are a number of things you should consider. You can’t just take an AP and put it anywhere in the building and expect it to work optimally. The first thing you should think about is the location of the users the APs will serve within that building. Users need access to the wireless network when they are at their desks but they might also need access to the Wi-Fi network when they are in conference rooms or other meeting areas. If that is the case, you should place the access points closer to those parts of the room or floor.

On 802.11 wireless networks there is a set of standards that defines what frequencies and what channels these particular networks might use. These standards are defined by IEEE and are used worldwide:

• 802.11a
• 802.11b
• 802.11g
• 802.11n

The standards above are the primary standards used today but there are also other standards in between those. There are many differences between all the standards, in terms of speed, distance, channels, and frequencies. Table 9.2 below summarizes the characteristics of the 802.11 standards:

Table 9.2 – 802.11 Characteristics