Users Guide
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.
IPv4 Layer-3 GRE Tunnel Network Diagram
Figure 20 IPv4 Layer-3 GRETunnel
IPv6 Layer-3 GRE Tunnel Network Diagram
Figure 21 IPv6 Layer-3 GRETunnel
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.
Layer-3 Traffic Flow
The traffic flow illustrated by Figure 20 and Figure 21 is as follows:
1. The frame enters the source controller (Controller-1) on VLAN 101.
The IP packet within the frame is routed through Controller-1 into the Layer-3 GRE tunnel.
2. The IP packet is encapsulated in a GRE packet.
3. The GRE packet enters the network on VLAN 10, is routed across the network to destination controller
(Controller-2), and then exits the network on VLAN 20.
Dell Networking W-Series ArubaOS 6.4.x | User Guide Network Configuration Parameters | 182