Comcast vs. BitTorrent
After several trials of using BitTorrent with Azuerus as the download manager, Comcast is seemingly dropping "passive" client connections. So if you start your BitTorrent download and leave it - with no active internet activity aside from the downloads - for anywhere from 15 minutes to a couple of hours, Comcast is dropping your DHCP account leaving you offline until you notice the problem and power-cycle your modem (or release\renew your ipconfig).
After realizing this was happening, I coded a very small EXE that utitlizes the Web Browser control supplied by Microsoft dating back to Visual Basic 5.0. The executable acts as any other browser but selects about a half-dozen websites and actively navigates them roughly every couple of minutes. Since using this EXE, Comcast "drops" have become minimal if non-existent. The last round of tests included 6 rather larger torrents (from 700mb to 4.09gb) and Azureus was able to continuously download all files. Comcast had not "dropped" the ISP connection in well over 3 days of passive downloading (mixed with our new "active" executable that is).
For those with Comcast, you can contact me and I'll be happy to give you the specs for the EXE or even provide a working copy: email@example.com