FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic.
Article Id 192579
SD-WAN configuration needs the ‘Performance SLA’ to find the WAN link failure detection.
While configuring it, define the target server or server such as Google DNS
However from the v6.2 and onward, FortiOS introduced factory default health checks which it can use as target server.

There are five predefined performance SLA profiles for newly created VDOMs or factory reset FortiGate:

- AWS.
- FortiGuard.
- Gmail.
- Google Search.
- Office 365.

View and configure the SLA profiles in Network -> Performance SLA.

Select the SD-WAN members under the participants and save the settings.

After configuring a health check, packet loss , latency, and jitter data for the SLA profiles will be visible.
If a value is colored red, it means that it failed to meet the SLA requirements.