D-Link Unified Access System
Software User Manual
02/15/2011
Page 96
Document 34CS3000-SWUM104-D10
If you enable L3 tunnels, we recommend that you enable and configure a separate VAP for clients that need to use this
feature. Configure clients that need L3 Tunneling to connect to the SSID with L3 tunnels enabled, but configure all other
wireless clients to use the VAP with L3 tunnels disabled.
In general, only clients that transmit and receive time-sensitive data while roaming need to take advantage of this feature.
<Link>Figure 43 shows a network with two APs that are controlled by a D-Link Unified Switch. The APs and switch are all
on different subnets.
Figure 43: L3 Roaming Example
Both of the APs in <Link>Figure 43 use the same default profile. The default profile has three virtual access points (VAPs)
enabled, and each VAP uses a different network (SSID). When users search for available wireless networks, all three SSIDs
appear in the list of networks. The laptop clients connect to the Company WLAN or Guest Network, and the VoIP phones
connect to the VoIP Network.
The L3 Tunnel feature is enabled on the VoIP network, but it is disabled on the Guest and Company WLAN networks since
those networks are primarily for data traffic. The VoIP network is for voice traffic. L3 Roaming uses IP tunneling so clients
appear to be on the same subnet even though the APs are on different subnets.
In the sample network that <Link>Figure 43 shows, the laptop users are connected to different WLAN networks on two
different APs. The Internet phone users are connected to the same WLAN network on two different APs. On the VoIP
Network, the phone users can seamlessly roam between AP1 and AP2 without service interruption or the need to re-
authenticate or change networks.
The Unified Switch uses a VLAN routing interface as a separate logical network configured for the L3 tunnel network. This
network is the L3 tunneling subnet and has a network address of 192.168.100.0.
Tunneling is not expected to work with port-based routing interfaces. All tunneled routing interfaces must be VLAN routing
interfaces. APs should not be attached via port-based routing interfaces as well.
AP1
Associated With:
3 VAPs
SSID - Guest Network
SSID - Company WLAN
AP2
3 VAPs:
SSID - Guest Network
SSID - Company WLAN
SSID - VoIP Network
AP1
SSID: Company WLAN
Associated With:
AP2
SSID: Guest Network
Associated With:
AP2
SSID: VoIP Network
Associated With:
AP1
SSID: VoIP Network
IP: 192.168.20.20
IP: 192.168.30.11
IP: 192.168.100.52
IP: 192.168.100.51
SSID - VoIP Network
Unified Switch
