Users Guide

Preemption
You can also enable or disable preemption as part of the tunnel-group configuration. Preemption is enabled by
default. (For CLI examples, see Enabling Preemption on page 194.)
The preemptive-failover option automatically redirects the traffic whenever it detects an active tunnel with a
higher precedence in the tunnel group.
When preemption is disabled, the traffic gets redirected to a higher precedence tunnel only when the tunnel
carrying the traffic fails.
Enabling a Tunnel Group
To enable this tunnel-group functionality, you must complete the following tasks:
1. Configure the member tunnel.
2. Enable tunnel keepalives on the tunnel interface.
3. Configure the tunnel group and set the group type to Layer-2 or Layer-3.
4. Add the member tunnels to the group.
Points to Remember
l When a tunnel is added to the tunnel group, the tunnel is used for data traffic only if it is the active tunnel in
the group.
l Standby tunnels do not carry any data traffic. However, all tunnels in the group continue to send and
receive keepalive packets.
l Only one type of tunnel can be placed into a tunnel group—either Layer-2 or Layer-3. That is, you can't have
a tunnel group consisting of both Layer-2 and Layer-3 tunnels.
l The default value of tunnel group type is Layer-3.
Regarding Layer-2 Tunnel Groups
When creating a Layer-2 tunnel group, keep in mind the following:
l All tunnels in a Layer-2 tunnel group must be tunneling the same VLAN.
l A Layer-2 tunnel can only be part of one tunnel group.
l A Dell Layer-2 tunnel-group is not interoperable with other vendors.
l You must set up Layer-2 tunnel groups between Dell devices only.
Configuring a Layer-2 or Layer-3 Tunnel Group Using the CLI
To configure a Layer-2 or Layer-3 tunnel group using the CLI:
(Controller-1) (config) #tunnel-group <tunnel_group_name>
(Controller-1) (config-tunnel-group)#mode {l2|l3}
(Controller-1)(config-tunnel-group)#tunnel <tunnel-id>
Example Configuration
The following is a sample configuration:
(Controller-1) (config) #tunnel-group branch_1
(Controller-1) (config-tunnel-group)#mode l2
Enabling Preemption
Execute the following command to enable preemption:
(Controller-1)(config-tunnel-group)#preemptive-failover
Dell Networking W-Series ArubaOS 6.4.x | User Guide Network Configuration Parameters | 194