WESM zl Management and Configuration Guide WT.01.28 and greater

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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 (J9051A)

■ the Redundant Wireless Services zl Module (J9053A)

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 through-

put, 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 1-78

for more information about this feature.

Redundant Wireless Services zl Module

The Redundant Wireless Services zl Module (J9053A) 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).