I have had the same problem as Judge Fred for the last month or more. Modem drops out and reboots many times a day and night. Light on front of modem goes white and I wait two minutes for reboot before internet reconnects.
I have been in constant contact with Telstra support and have had the problem raised to Level 2 support without any resolution. I was really getting sick of waiting 30 minutes to talk with someone and being asked what name I would prefer to be called
After trying everything else I uninstalled Telstra Internet Optimiser from my modem and hey presto - problem solved.