Internet disappears if doing intense upload/download
I have a weird situation where if I upload/download for awhile, my internet dies, but the program that is using the bandwidth works fine. For example, I use BitTorrent to upload/download a file and it is working in the background. Say about 1 hour later, I try to open up Firefox to browse the internet. It will show that it cannot connect but my BitTorrent is still uploading/downloading. If I turn off BitTorrent, my internet is STILL dead. I have to manually pull the plug on my router and wait like 30 minutes before the internet goes back up. Is it my router or is it my ISP (Comcast)? Any ideas?