Wireless/Redundant Edge Services xl Module Management and Configuration Guide WS.01.03 or greater

3-3

Wireless Local Area Networks (WLANs)

Overview

A wireless LAN (WLAN) is a LAN that uses a wireless medium. The WLAN

might include multiple radio ports (RPs), each of which is identified by an

individual basic service set identifier (BSSID), and each of which transits

traffic to and from a set of wireless stations. These stations can roam between

RPs, which as long as they share the same SSID, provide access to the

same WLAN.

By default, all RP radios adopted by a Wireless Edge Services xl Module

support all WLANs that you enable on that module. In “Configuration Options:

Normal Versus Advanced Mode” on page 3-4, you will learn about how the

module assigns these WLANs to BSSIDs on each RP radio, which affects which

WLANs operate in open and which in closed system. Mastering these concepts

will help you better design your network, and is particularly important when

you plan to configure more than four WLANs.

The WLAN defines settings that control the wireless communications. These

range from the method that wireless stations must use to authenticate them-

selves to the encryption algorithms that protect data to the parameters by

which stations compete for access to the wireless medium. When you config-

ure the WLAN, you must choose these settings, as described in “Configuring

a WLAN” on page 3-27 and “Traffic Management (QoS)” on page 3-71.

Because all RPs in a WLAN must agree upon settings, the Wireless Edge

Services xl Module, as a single wireless controller, greatly simplifies configu-

ration. After you configure and enable a WLAN on the module, the module can

automatically configure these settings on all adopted RPs.

The RPs send and receive traffic in these WLANs. The traffic that they receive

from wireless stations, they forward (via Radio Port virtual LANs [VLANs]) to

the Wireless Edge Services xl Module, which in turn forwards this traffic in

an uplink VLAN. The module can:

■ forward all traffic from a WLAN in the same uplink VLAN (manual VLAN

assignment)

■ forward traffic in different uplink VLANs depending on the identity of the

user that sent the traffic (dynamic VLAN assignment)

You will learn about both of these options in “VLAN Assignment” on page 3-62.