ZyXEL NBG-419N Guia Do Utilizador

 Appendix D Wireless LANs

NBG-419N User’s Guide

An ESSID (ESS IDentification) uniquely identifies each ESS. All access points and 
their associated wireless stations within the same ESS must have the same ESSID 
in order to communicate.

Figure 171   Infrastructure WLAN

A channel is the radio frequency(ies) used by IEEE 802.11a/b/g wireless devices. 
Channels available depend on your geographical area. You may have a choice of 
channels (for your region) so you should use a different channel than an adjacent 
AP (access point) to reduce interference. Interference occurs when radio signals 
from different access points overlap causing interference and degrading 
performance.

Adjacent channels partially overlap however. To avoid interference due to overlap, 
your AP should be on a channel at least five channels away from a channel that an 
adjacent AP is using. For example, if your region has 11 channels and an adjacent 
AP is using channel 1, then you need to select a channel between 6 or 11.

A hidden node occurs when two stations are within range of the same access 
point, but are not within range of each other. The following figure illustrates a 
hidden node. Both stations (STA) are within range of the access point (AP) or