Tunnel Concentrator lets you configure GRE point-to-point tunneling between wireless access points and the Tunnel Concentrator application, which runs on the Universal Compute Platform. Tunnel Concentrator serves as the tunnel termination point and forwards the traffic to the data center, where the traffic can be aggregated.
To provision tunnels, administrators configure GRE tunneling settings for a given VLAN and map the VLAN across the WLAN network. All GRE tunneling sessions get initiated by the access point, which generates tunnels dynamically on a per user traffic flow basis for the VLAN. As a user's traffic flows across the AP, the AP adds the GRE encapsulation settings that were mapped to that VLAN, which generates the tunnel between the AP and Tunnel Concentrator. If IPSec is deployed, the AP also encrypts the GRE header. The AP then forwards the traffic through the tunnel towards Tunnel Concentrator.
After receiving the traffic, Tunnel Concentrator decrypts received packets (if IPSec is deployed), removes the GRE header, and forwards the traffic to the appropriate location in the traffic data center. For any response traffic, the process flow occurs in the reverse order.
Note
IPSec is supported only when you deploy Tunnel Concentrator with ExtremeCloud IQ Controller as the management application.
Note
GRE tunneling is supported only between the access point and Tunnel Concentrator. It is not supported to deploy a NAT router in the middle of the tunnel.