User's Manual

Appendix D Wireless LANs
B222s User’s Guide
231
An ESSI D ( ESS I Dent ificat ion) uniquely ident ifies each ESS. All access point s and t heir associat ed
wir eless client s wit hin t he sam e ESS m ust have the sam e ESSI D in order t o com m unicat e.
Figure 164 I nfrastructure WLAN
Channel
A channel is t he radio frequency( ies) used by wireless devices t o t ransm it and receive data.
Channels available depend on your geographical ar ea. You m ay have a choice of channels ( for your
region) so you should use a channel different from an adjacent AP ( access point ) t o reduce
int erference. I nt erference occurs when radio signals from different access point s overlap causing
int erference and degrading perform ance.
Adj acent channels part ially overlap however. To avoid interference due t o overlap, your AP should
be on a channel at least five channels away from a channel t hat an adj acent AP is using. For
exam ple, if your region has 11 channels and an adjacent AP is using channel 1, t hen you need t o
select a channel bet ween 6 or 11.
RTS/CTS
A hidden node occurs when two stat ions are wit hin range of the sam e access point, but are not
wit hin range of each ot her. The following figur e illust rat es a hidden node. Both st at ions ( STA) are
wit hin range of t he access point ( AP) or wireless gat eway, but out- of- range of each ot her, so t hey