User's Manual

9 Managing the Network
230 Installation and User Guide: Airgo Access Point
enabling retention of the same IP address, clients can continue their conversations without
interruption.
Layer-3 Mobility requires wireless client reauthentication, and delays can occur for some
authentication methods. For example, if the clients use WPA-EAP for authentication, then Layer-3
roaming still requires clients to be reauthenticated by an external RADIUS server. Delays can occur
while authentication messages are exchanged between the AP and the RADIUS server. However, if
WPA-PSK or WEP methods are used for authentication, the client will be reauthenticated on the
new AP to which it has roamed, thereby avoiding the latency introduced by the external RADIUS
server.
When creating a Layer-3 Mobility zone, all APs should be managed by the same management
domain (NMS Pro or NM Portal). There are two methods of configuring Layer-3 Mobility:
• Layer-3 Mobility Using VLANs (See “Layer-3 Mobility Using VLANs”)
• Layer-3 Mobility Using Tunneling (See “Layer-3 Mobility Using Tunneling”)
Layer-3 Mobility Using VLANs
This approach requires the use of VLANs to enable seamless Layer-3 Mobility. It is suitable for
small networks with a number of subnetworks because traffic from all subnetworks is bridged by
the APs in separate VLANs. Client stations roaming between APs are kept within the same VLAN
and, hence, remain in a single subnet. Layer-3 mobility is supported with interface VLANs and user
VLANs (Figure 168).