ZyXEL Communications NWA3560-N User Manual page 289

An ESSI D ( ESS I Dent ificat ion) uniquely ident ifies each ESS. All access point s and t heir associat ed
wireless client s wit hin t he sam e ESS m ust have t he sam e ESSI D in order t o com m unicat e.
Figure 124 I nfrast ruct ure WLAN
Channel
A channel is t he radio frequency( ies) used by wireless devices t o t ransm it and receive dat a.
Channels available depend on your geographical area. You m ay have a choice of channels ( for your
region) so you should use a channel different from an adj acent 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 int erference 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 adj acent 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 t wo st at ions are wit hin range of t he sam e access point , but are not
wit hin range of each ot her. The following figure illust rat es a hidden node. Bot h 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
NWA3000-N Series User's Guide
Appendix C Wireless LANs
289