I wouldn’t think so, as the graphs show that the uplink is not maxed out, so the TCP returned ACKs can get back up safely. I think the delay is all in the downstream with the PPP LCP pings being stuck behind a queue of stuff heading down, but I can’t be certain about this at all.
Actually, that would mean I was talking nonsense before and the queue management would need to be in the server’s OS, no?
Now I think about it again, I’m tentatively assuming that there’s no upstream ingress queue or a minimal length one to be managed by [what?] upstream-bound. Not thinking straight, tired and full of drugs. The upstream ingress queue is in the modem, yes? But I presume it could effectively be managed by an OS further back (ie nearer to the source)?