Dual mode SLBC with two FortiController-5103Bs

This example describes the basics of setting up a dual mode SLBC cluster that consists of two FortiController-5103Bs, installed in chassis slots 1 and 2, and three FortiGate-5001C workers, installed in chassis slots 3, 4, and 5. This SLBC configuration can have up to 16 10Gbit network connections.

The two FortiControllers in the same chassis to operate in dual mode to double the number of network interfaces available. In dual mode, two FortiControllers load balance traffic to multiple workers. Traffic can be received by both FortiControllers and load balanced to all of the workers in the chassis. In a dual mode configuration the front panel interfaces of both FortiControllers are active.

In a dual mode FortiController-5103B cluster, up to 16 10Gbyte network interfaces are available. The interfaces of the FortiController in slot 1 are named fctrl/f1 to fctrl/f8 and the interfaces of the FortiController in slot 2 are named fctr2/f1 to fctrl2/f8.

All networks have single connections to the first or second FortiController. It is a best practice in a dual-mode configuration to distribute traffic evenly between the FortiControllers. So in this example, ingress traffic from the internet is processed by the FortiController in slot 1 and egress traffic for the internal network is processed by the FortiController in slot 2.

Redundant connections to a single network from two dual-mode FortiControllers in same chassis is only supported if you configure link aggregation.

One or more heartbeat links are created between the FortiControllers. Redundant heartbeat links are recommended. The heartbeat links use the FortiController front panel B1 and B2 interfaces.

If one of the FortiControllers fails, the remaining FortiController keeps processing traffic received by its front panel interfaces. Traffic to and from the failed FortiController is lost.