WESM zl Management and Configuration Guide WT.01.XX and greater

1-76

Introduction

Redundancy Groups

A good network design builds in redundancy so that, in the unlikely event of

a hardware or link failure, users continue to access the resources that they

need. To provide redundancy for your wireless network, you can create a

redundancy group using various combinations of the following two modules:

■ the Wireless Edge Services zl Module (J9001A)

■ the Redundant Wireless Services zl Module (J9003A)

Because new members of a redundancy group add failover capabilities,

processing power, and throughput, but not licenses, the most typical design

includes a single primary module and one or more redundant modules. In

addition to enabling high-availability, a redundancy group can serve these

functions:

■ adding capacity—You can configure the redundant modules to be active

at all times, not only when the primary module fails. In this case, the

modules load balance the groups’ RPs between them. Each module adds

400 Mbps of throughput, which might be important in a busy network.

■ providing seamless Layer 2 roaming for Web-Auth—See “Roaming

Between RPs on Different Wireless Edge Services zl Modules at Layer 2”

on page 1-82 for more information about this feature.

Redundant Wireless Services zl Module

The Redundant Wireless Services zl Module (J9003A) is designed primarily to

provide cost-effective failover capabilities. The redundant module provides

the same capabilities as the Wireless Edge Services zl Module, or primary

module, with one exception: the redundant module does not include any RP

licenses, and you cannot add licenses to it. Instead, the redundant module is

authorized to use the primary module’s licenses in certain situations, which

are discussed later in this section.

To enable a redundant module to back up one or more primary modules that

are installed in the same or in different wireless services-enabled switches,

you must configure the modules as part of a redundancy group. The redundant

module can then use a primary module’s RP licenses to adopt RPs in various

circumstances (which depend on the redundant module’s operation mode as

described later in this section).