I had that happen on my Comcast connection but it was always between 2-3pm. It wouldn't drop completely though it would just suddenly start dropping 95% of the packets and ping times would go up to 2-3 seconds. I pestered them about it for a month and eventually a tech happened to arrive while it was happening, he called their CO and they found they had a network switch that was intermittently malfunctioning. After that it never happened again and for helping them troubleshoot it they gave me 4 years of free HBO and the cell number for one of their engineers so I wouldn't have to sit through tier 1 and 2 support again.