Before ArubaOS 6.3, a single GRE tunnel is only allowed to exist between Mobility Controllers or GRE capable End point devices. This causes network outages as it goes down.
ArubaOS 6,3, brings in "Tunnel Group" feature where multiple GRE tunnels can be bundled between GRE capable end point devices to form a logical tunnel group.
Tunnel-group ensures that we have a redundant Tunnels to forward the traffic if the active tunnel fails.
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Automatic shift to the secondary GRE tunnel, when the primary tunnel goes down
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Works on the keep alive mechanism between tunnel end points to sense the tunnel availability.
Environment : This article applies to all Aruba controller running ArubaOS version 6.3 and above.
Network Topology :
L2 GRE: Between Aruba Standalone Master Controllers (OR) Aruba Master-Local Setups
L3 GRE: Between any two GRE End Points
When it comes to configuration, we first configure GRE tunnels between end points and then map the tunnels into a logical tunnel group. Below screen shot from the command line, shows the configuration of individual tunnels and then the tunnel group:
Note: The first added tunnel in the tunnel group becomes active tunnel.
Once the tunnel group is setup, we need to configure an access list (ACL) to redirect all the traffic to tunnel group.
Below command line screenshot gives a glimpse of show commands for tunnels and tunnel groups:
The "Active tunnel ID" column in the "Show tunnel-group" shows the active tunnel in the group and also if the Preemption is enabled.
Note: One of the tunnel in the tunnel group should show as active.