Ping the modem every 30 seconds
Ping the "internet" every 5 minutes
if either ping fails
    stop PPPOE process
    power-cycle modem
    while(modem not responding to pings for > 30 seconds after last power-cycle)
        power-cycle modem
    wait 10 seconds
    start PPPOE process
    wait 10 seconds
    ping internet
    if internet still not up, repeat entire process