IronPort Systems ZyAIR B-4000 - Manual (Page 229)

ZyAIR B-4000 Hot Spot Gateway
Wireless LAN and IEEE 802.11 C-3
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.