ZyXEL Communications P-660HW-T - V2, User Manual

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P-660HW-T v2 User’s Guide
Appendix K Wireless LANs 323
Figure 184 Infrastructure WLAN
Channel
IEEE802.11a/b/g wireless devices operate in the 2.4GHz radio band. This range of frequencies
is divided up into channels.The channels available depend on your geographical area. You
may have a choice of channels (for your region) so you should use a different channel from an
adjacent AP (access point) to reduce interference. Interference occurs when radio signals from
different access points overlap, distorting the signal 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 and 11.
RTS/CTS
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 wireless gateway, but out-of-range of each other,
so they cannot "hear" each other, that is they do not know if the channel is currently being
used. Therefore, they are considered hidden from each other.