Reference

• Technical Tip : FortiGate BFD implementation and examples (Bidirectional Forwarding Detection for OSPF and BGP): https://community.fortinet.com/t5/FortiGate/Technical-Tip-FortiGate-BFD-implementation-and-examples/ta-p/190484

• BFD: https://www.cisco.com/en/US/docs/ios/12_4t/ip_route/configuration/guide/t_bfd.html#wp1053332