ZyXEL Communications B-420 User Manual

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ZyAIR B-420 Wireless LAN Ethernet Adapter and Bridge 
D-2                                                                                                   Wireless LAN and IEEE 802.11 
Spread Spectrum (DSSS) and Frequency-Hopping Spread Spectrum (FHSS), in the 2.4 to 2.4825 GHz 
unlicensed ISM (Industrial, Scientific and Medical) band. The third method is infrared technology, using 
very high frequencies, just below visible light in the electromagnetic spectrum to carry data. 
Ad-hoc Wireless LAN Configuration 
The simplest WLAN configuration is an independent (Ad-hoc) WLAN that connects a set of computers 
with wireless nodes or stations (STA), which is called a Basic Service Set (BSS). In the most basic form, a 
wireless LAN connects a set of computers with wireless adapters. Any time two or more wireless adapters 
are within range of each other, they can set up an independent network, which is commonly referred to as 
an Ad-hoc network or Independent Basic Service Set (IBSS). See the following diagram of an example of 
an Ad-hoc wireless LAN. 
 
Diagram D-1 Peer-to-Peer Communication in an Ad-hoc Network 
Infrastructure Wireless LAN Configuration 
For infrastructure WLANs, multiple access points (APs) link the WLAN to the wired network and allow 
users to efficiently share network resources. The access points not only provide communication with the 
wired network but also mediate wireless network traffic in the immediate neighborhood. Multiple access