WESM zl Management and Configuration Guide WT.01.28 and greater

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Introduction
Layer 2 and Layer 3 Roaming Between RPs and Modules
into different VLANs, complicating the roaming process. When a station roams to
an RP adopted by a different module, the station’s IP address is no longer valid, and
the station loses its active sessions.
Wireless Edge Services zl Modules use network, or Layer 3, roaming to solve this
problem. Figure 1-26 illustrates a network that requires Layer 3 roaming. The module
on the left places wireless stations in WLAN A in VLAN 1 while the module on the
right places stations in WLAN A in VLAN 20.
Figure 1-26. Network Requiring Layer 3 Roaming
Note It is important that the difference in subnetwork be reflected in different VLAN IDs
because Layer 3 roaming relies on a changing VLAN ID to detect a Layer 3 roam.
In other words, the two modules in Figure 1-26, which are in different subnetworks,