Layer-3 tunneling involves the extended application of the CAPWAP protocol (control and provisioning of wireless access points) as used by WLAN controllers (WLC) to manage WLAN access points. It allows WLAN data to be fed into the LAN via a central WLAN controller by establishing a direct data tunnel between the WLAN controller and the access point. For configuration, one of the available WLC tunnel interfaces has to be set in the logical network profile of the WLC under. The data traffic from that SSID is now directed to the selected WLC tunnel interface of the WLC. The WLC tunnel interface can now be used for an ARF network or in the LAN bridge of the WLC.
Layer-3 tunneling is ideal for environments operating unmanaged switches or where no further VLAN configuration of the switches is possible. This allows data tunnels to be set up very quickly and easily without needing a VLAN infrastructure between the WLAN controller and access point to isolate the data traffic of individual SSIDs from one another. A VLAN infrastructure is only required at the transfer point between the WLAN controller and the local networks because data from the individual SSIDs is transported in a layer-3 tunnel between the access point and WLAN controller. Alternatively, the WLAN controller can use its router function to route data delivered via the tunnel to other IP networks or to the Internet.