In reply to a post by candlerb:

In reply to a post by prlzx:

Last time the router showed that TX / RX for the Internet was stuck at 0 but otherwise it thought it was still connected so was not triggering any automatic reconnection. I don't know the correct terminology except that people sometimes talk about a PPP session "going stale".

Does your router allow "LCP keepalives" to be enabled? That should detect a stale session, and then the router should tear it down and start a fresh one.