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

12-2
Configuring Tunnels with Generic Routing Encapsulation
Overview
Overview
The ProCurve Wireless Edge Services xl Module can forward all of a wireless
LAN’s (WLAN’s) traffic to another device to be processed. To enable this
feature, you must complete these steps:
1. Configure a Generic Routing Encapsulation (GRE) tunnel to that device.
2. Configure your Wireless Edge Services xl Module to forward all traffic
received on a particular WLAN over that GRE tunnel.
A GRE tunnel is a virtual point-to-point connection between two devices.
Traffic sent over the tunnel is encapsulated with a delivery header, and the
inner layers are transparent to intervening devices (that is, not seen by them).
When you map a WLAN to a GRE tunnel interface, the Wireless Edge Services
xl Module follows these steps:
1. It receives a frame from a station associated to the WLAN.
2. It removes the 802.11 header.
3. It encapsulates the IP packet with a GRE header.
Note The Wireless Edge Services xl Module only encapsulates and forwards IP
packets over the tunnel.
4. It encapsulates the GRE header with a delivery IP header:
• The delivery header’s source IP address is that for the tunnel source
endpoint.
• The delivery header’s destination IP address is that for the tunnel
destination endpoint.
When the Wireless Services xl Module receives a packet over the tunnel, it
removes the delivery IP header and the GRE header. The module then looks up
the destination IP address in the original header. If this address is valid, the
module encapsulates the packet in an 802.11 header and forwards the resulting
frame toward the appropriate RP, just as it would any packet destined to a WLAN.
The destination endpoint of a GRE tunnel on a Wireless Edge Services xl
Module can be any ProCurve GRE-capable device such as:
■ a ProCurve Secure Router 7000dl Series
■ another Wireless Edge Services xl Module
■ a Redundant Wireless Services xl Module