Wireless/Redundant Edge Services xl Module Management and Configuration Guide WS.02.xx and greater

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Introduction
Redundancy Groups
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 xl Module (J9001A)
■ the Redundant Wireless Services xl 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 xl Modules at Layer 2”
on page 1-81 for more information about this feature.
Redundant Wireless Services xl Module
The Redundant Wireless Services xl Module (J9003A) is designed primarily to
provide cost-effective failover capabilities. The redundant module provides
the same capabilities as the Wireless Edge Services xl 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).