Chapter 1 What’s New for FortiOS 5.0 : Other new features : New HA mode: Fortinet redundant UTM protocol (FRUP)
  
New HA mode: Fortinet redundant UTM protocol (FRUP)
FortiOS 5.0 includes an extension to the FotiGate Clustering Protocol that combines Switching HA and Firewall HA into a single unified design. This feature is initially available on the FortiGate-100D and will be considered for other models in future releases.
A FRUPS setup consists of 2 (and only 2) identical FortiGate-100D units. The setup supports dual redundant HA links between the units for sharing session and configuration data.
To see a FRUP example, please refer to Cookbook Beta - FortiGate Redundant UTM Protocol.