Foundry Networks IRONPOINT 250 - Manual (Page 26)

Foundry IronPoint 250 Installation Guide
3-2 © 2007 Foundry Networks, Inc. August 2007
Infrastructure Wireless LAN
The IronPoint 250 is designed to provide access to a wired LAN for wireless workstations. An
integrated wired/wireless LAN is called an Infrastructure configuration. A Basic Service Set (BSS)
consists of a group of wireless PC users and an access point that is directly connected to the wired
LAN. Each wireless station in this BSS can communicate with any device in its wireless group via a
radio link, or access other computers or network resources in the wired LAN infrastructure via the
access point.
The infrastructure configuration not only extends the accessibility of wireless PCs to the wired LAN,
but also increases the effective wireless transmission range for wireless PCs by passing their signal
through one or more access points.
A wireless infrastructure can be used for access to a central database, or for a connection between
mobile workers, as shown in the following figure.
Figure 3-1. Infrastructure Wireless LAN
Infrastructure Wireless LAN for Roaming Wireless PCs
The Basic Service Set (BSS) defines the communications domain for each access point and its
associated wireless clients. The BSS ID is a 48-bit binary number based on the access point’s
wireless MAC address, and is set automatically and transparently as clients associate with the
access point. The BSS ID is used in frames sent between the access point and its clients to identify
traffic in the service area.
The BSS ID is only set by the access point, never by its clients. The clients only need to set the
Service Set Identifier (SSID) that identifies the service set provided by one or more access points.
The SSID can be manually configured by the clients, can be detected in an access point’s beacon, or
can be obtained by querying for the identity of the nearest access point. For clients that do not need
to roam, set the SSID for the wireless card to that used by the access point to which you want to
connect.
A wireless infrastructure can also support roaming for mobile workers. More than one access point
can be configured to create an Extended Service Set (ESS). By placing the access points so that a
Server
Switch
Desktop PC
Access Point
PC with Wireless
PCI Adapter
Notebook with Wireless
PC Card Adapter
Wired LAN Extension to
Wireless Clients