ZyXEL Communications ZYAIR G-4100 User Manual page 212

ZyAIR G-4100 User's Guide
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 5 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 points can provide wireless coverage for an entire building or campus. All
communications between stations or between a station and a wired network client go through the
access point.
The Extended Service Set (ESS) shown in the next figure consists of a series of overlapping BSSs
(each containing an Access Point) connected together by means of a Distribution System (DS).
Although the DS could be any type of network, it is almost invariably an Ethernet LAN. Mobile nodes
can roam between access points and seamless campus-wide coverage is possible.
N Wireless LAN and IEEE 802.11