Chapter 9 High Availability for FortiOS 5.0 : Configuring and connecting HA clusters : Example: HA and redundant interfaces
  
Example: HA and redundant interfaces
On FortiGate models that support it you can combine two or more interfaces into a single redundant interface. A redundant interface consists of two or more physical interfaces. Traffic is processed by the first physical interface in the redundant interface. If that physical interface fails, traffic fails over to the next physical interface. Redundant interfaces don’t have the benefit of improved performance that aggregate interfaces can have, but they do provide failover if a physical interface fails or is disconnected.
Figure 196: Example cluster with a redundant interfaces
This example describes how to configure an HA cluster consisting of two FortiGate-620B units with a a redundant interface connection to the Internet and to an internal network. The connection to the Internet uses port1 and port2. The connection to the internal network uses port3 and port4. The HA heartbeat uses port5 and port6.
The redundant interfaces are also configured as HA monitored interfaces.