Wireless/Redundant Edge Services xl Module Management and Configuration Guide WS.02.xx and greater

12-3
Configuring Tunnels with Generic Routing Encapsulation
Overview
For example, you might establish a wireless network at a remote office. You want
all the wireless traffic to return to the main office, so you create a GRE tunnel
from the Wireless Edge Services xl Module to the router at the main office.
You could also tunnel traffic to a WAN router to protect your internal network
from guests in a WLAN that is intended to provide access to the Internet only.
The Wireless Edge Services xl Module receives guest traffic and readies it for
transmission in the Ethernet network, as usual. However, the module then
encapsulates the traffic and sends it over the tunnel to the Internet router—
the guest traffic never interacts with your internal network.
Manually creating a GRE tunnel to another Wireless Edge Services xl Module
is not typical, but it is supported. When you configure your module to forward
traffic over a tunnel to another module, you are making the first module
behave somewhat like an RP that is adopted by the second module: the second
module handles the task of forwarding the traffic onto the Ethernet network.
However, the first module still handles the security settings for the WLAN.
Note Wireless Edge Services xl Modules in a Layer 3 mobility domain also tunnel
traffic. However, the modules create the tunnels automatically; you should not
create them manually. If you want to set up Layer 3 roaming, see Chapter 9:
Fast Layer 2 Roaming and Layer 3 Mobility.