Hi @seb82. I’ve read all the thoughtful comments which follow and I have no substantive additions. Indeed, I’d be quite reticent to correct or add much to the responses of the experts who have responded. 
But may I made a “side” comment? We are fighting Comcast over the exact same issue. Their network seems to periodically drop packets. We;ve verified this with PingPlotter and other tools. This is not a “Peplink issue.” We’ve tried WAN health checks via ping and DNS look-up and no matter what we do vis-a-vis frequency, wait time, etc, periodically the Comcast WANs at two locations are marked off-line by the Peplink routers as a result of failing health checks.
Complaints to Comcast have resulted in – predictably – no relief. No “outages” and no help from them. We’re going to continue fighting but we’re also looking for alternatives to this very shaky ISP. (We’ll see how this search goes --given that the US Government is fine with monopolies. We’re not optimistic we’ll find a reasonable, cost-effective solution.)