Users Guide

Table Of Contents
111| Network Configuration Parameters Dell Networking W-Series ArubaOS 6.5.x| User Guide
Figure 17 Layer-2 GRETunnel
The traffic flow illustrated by Figure 17 is as follows:
1. The frame enters the source controller (Controller-1) on VLAN 101.
The frame is bridged through Controller-1 into the Layer-2 GRE tunnel.
2. The frame is encapsulated in a GRE packet.
3. The GRE packet enters the network on VLAN 10, is routed across the network to the destination controller
(Controller-2), and then exits the network on VLAN 20.
The source IP address of the GRE packet is the IP address of the interface in VLAN 10 in Controller 1.
4. The frame is de-encapsulated and bridged out of the destination controller (Controller-2) on VLAN 101.
About Layer-3 GRE Tunnels
The benefit of Layer-3 GRE tunnels is that broadcasts are not flooded through the tunnel, so there's less
wasted bandwidth and less load on the controllers. The forwarding method for a Layer-3 GRE tunnel is routing.
By default, GRE tunnels are in IPv4 Layer-3 mode.
Figure 18 IPv4 Layer-3 GRETunnel
Figure 19 IPv6 Layer-3 GRETunnel
IPv6 encapsulated in IPv4 and IPv4 encapsulated in IPv6 are not supported. The only Layer-3 GRE modes supported
are IPv4 encapsulated in IPv4 and IPv6 encapsulated in IPv6.