FortiGate - Is Performance SLA required for failover?

[asta17]

Have a client that had a primary internet failure, and the backup internet did not seem to come online. It was a quick blip so I didn't dive into it at the time, but just going over the config the only thing I can really notice is that in the SD WAN the Performance SLA was only set up for the primary connection rather than all connections in the SD WAN.

So, as the title says, is Performance SLA required for internet failover to occur, or do I need to keep digging for a reason why it didn't happen?

[parteeksharma]

Hi Asta17,

For the link failover to work properly, the performance SLA is needed and it should be setup for all the links configured in sdwan.  Performance SLA is created so that, If a link fails all of the health checks, the routes on that link are removed from the SD-WAN link load balancing group, and traffic is routed through other links. When the link passes SLA, the routes are reestablished. This prevents traffic from being sent to a broken link and getting lost. For more details, kindly check below link:

https://docs.fortinet.com/document/fortigate/7.2.4/administration-guide/584396/performance-sla

Regards,
Parteek