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

5-39
Radio Port Configuration
Configuring Client Roaming
For more information on configuring data rate settings and power levels,
see “Configuring Rate Settings” on page 5-15 and “Setting the Desired
Radio Power” on page 5-14.
Roaming can be slowed when the WLAN to which the station connects
requires the station to authenticate itself. With fast roaming, RPs receive keys
for stations supported by neighboring RPs, so that if a station should roam,
the new RP can immediately associate with it. A Wireless Edge Services xl
Module supports fast roaming between all RPs adopted on that module. See
Chapter 3: Wireless Local Area Networks (WLANs) to learn how to enable
fast roaming capabilities, such as Pairwise Master Key (PMK) Caching and
Opportunistic Key Caching.
Stations cannot fast roam between RPs adopted by different modules. For
this reason, it is a good idea to allocate nearby RPs—for example, all RPs on
the same floor or in the same building—to the same module. See “Setting the
Adoption Preference Identification” on page 5-20 to learn how to influence
which module adopts an RP.
Stations can roam between RPs adopted by different modules. In many cases,
the simple roam is more than adequate. However, if the station connects to a
WLAN that uses Web authentication, then the connection will be dropped
when the station roams to a new RP.
Authentication to the new RP using 802.1X, on the other hand, typically occurs
in the background. For traditional wireless applications, the simple roam may
not even register. For VoWLAN devices, the call may be temporarily disrupted,
so you should take particular care to have the same Wireless Edge Services xl
Module adopt all RPs in an area that supports such devices.