WESM zl Management and Configuration Guide WT.01.03 and greater

9-10
Fast Layer 2 Roaming and Layer 3 Mobility
Overview
Table 9-1. Enabling the Best Roaming Between Different Wireless Edge Services
zl Modules
In summary, follow these guidelines:
■ The Wireless Edge Services zl Module automatically enables fast Layer 2
roaming between RPs on the same module. (Layer 3 roaming is not a
concern for roaming on a single module.)
■ Except when using Web-Auth, modules automatically handle seamless
(but not necessarily fast) Layer 2 roaming between RPs on different
modules.
■ Fast roaming between modules at Layer 2 requires extra configuration
and is possible in a WLAN that requires WPA/WPA2 with 802.1X. See
“Configuring Fast Layer 2 Roaming for WPA/WPA2 with 802.1X” on
page 9-12.
WLAN Security
Option
Layer 2 Roam
Without Special
Configuration
Best
Layer 2
Roam
Requirements for
Best Layer 2
Roam
Layer 3 Roam
Without Special
Configuration
Best
Layer 3
Roam
Requirements for
Best Layer 3
Roam
open
authentication
seamless seamless none not seamless seamless modules in the
same Layer 3
mobility domain
authentication
with a static key
(static Wired
Equivalent Privacy
[WEP] or WPA-
preshared key
[PSK])
seamless seamless none not seamless seamless modules in the
same Layer 3
mobility domain
Web-Auth not seamless seamless 156 RP limit,
either:
•a single
module adopts
all RPs
• modules in the
same
redundancy
group
not seamless seamless modules in the
same Layer 3
mobility domain
dynamic WEP or
RADIUS MAC
authentication
seamless seamless none not seamless seamless modules in the
same Layer 3
mobility domain
WPA/WPA2 with
802.1X
seamless fast • PMK caching
•pre-
authentication
not seamless seamless modules in the
same Layer 3
mobility domain