Which interfaces on FortiSwitch send out FortiLink discovery frames by default in order to detect...

Fortinet FortiLink Protocol:The FortiLink protocol is Fortinet's proprietary mechanism for managing FortiSwitch units from a FortiGate firewall. It simplifies configuration and security policy enforcement across the connected network devices.

Auto-Discovery:FortiLink's auto-discovery feature means that by default, all ports on a FortiSwitch will actively send out discovery frames. This allows them to locate a FortiGate device that has a FortiLink interface enabled, streamlining the device management process.

No Configuration Needed:You don't have to manually configure individual ports for FortiLink discovery on FortiSwitch devices.

References

FortiSwitchOS FortiLink Guide (FortiSwitch Devices Managed by FortiOS 7.2):Refer to pages 13 and 14 for details on zero-touch management and FortiLink configuration. [https://fortinetweb.s3.amazonaws.com/docs.fortinet.com/v2/attachments/27f63c72-b083-11ec-9fd1-fa163e15d75b/FortiSwitchOS-7.2.0-FortiLink_Guide%E2%80%94FortiSwitch_Devices_Managed_by_FortiOS_7.2.pdf ]