High availability (HA) refers to the ability of a system to have a lower chance of failing during normal operation. Many Fortinet products include HA features that most commonly allow two or more devices to appear to function as one. In these redundant configurations, often called clusters, the devices in the cluster share information about their activities so that if one of the devices in the cluster fails the other can automatically take over full operation with only a minor interruption.
Fortinet products employ a wide variety of technologies to achieve HA and some of these HA technologies allow Fortinet products to join into cluster with third party products. For example, FortiOS and FortiGates support the following HA technologies:
- The FortiGate Clustering Protocol (FGCP) a proprietary HA technology in which a cluster of two or more FortiGate units operate as a cluster.
- The FortiGate Session Life Support Protocol (FGSP) is similar to the FGCP but relies on external routers or load balancers.
- Virtual Router Redundancy Protocol (VRRP) an industry standard protocol that can be used for HA between FortiGate units or between FortiGate units and 3rd party routers that also support VRRP.
- Session-Aware Load Balancing Clustering (SLBC) combines FortiController-5000 series load balancers with clusters of FortiGate-5000 workers.
- Enhanced Load Balancing Clustering (ELBC) combines FortiSwitch-5000 series load balancers with clusters of FortiGate-5000 workers.
- Content clustering that uses FortiSwitch-5203Bs or FortiController-5902Ds to load balance content sessions to FortiGate-5000 workers.