SDWAN vs Link-Monitor for Backup Internet

[kiral9]

I'm using Fortigate 70G with Comcast broadband in WAN1 and a 5G router for backup connected to WAN2. What's the best way to configure failover? I just kind of assumed that I should use SDWAN, but if I'm being honest, I don't really need any of the SDWAN "features." Since the 5G router will have a cost-per-bandwidth, I really only want to use it if/when Comcast is down.

Can I achieve this type of failover configuration with SDWAN or am I better off just doing link-monitor?

[funkylicious]

you could use sdwan but this would require some reconfiguration on the FGT in order to use the interfaces in the sdwan zone.

configuring a link-monitor would be easier with no major changes in the config or downtime, just make sure that you have the route and firewall policies in place for the backup link.

[xshkurti]

You can also use SDWAN and manually select outgoing interface with preference for WAN link and leave the second backup for 5G mettered connection.

If first interface can not handle traffic because of SLA failure, then second interface will be used.
You can might need sdwan features for latter usage, so the configuration change in the future will not be painful.