I worked with my ISP (RCN). The engineer was able to put a sniffer on my external Firewall IP address. I was able to do the same on my private IP address port of the firewall. What we noticed was that all of the ports stated on Bungie's website were flowing during the download. However the age of my firewall (SONICWALL SOHO3) was not passing all of the "keep alive" packets being sent by Bungie or xbox live. It would drop these due to traffic. I replaced the firewall with a Linksys n7500 and made no changes for ports and it just started working. In short Destiney puts a huge load on the processor of the router/firewall. My old firewall could not keep up with it and that would cause my disconnects. I was able to finish the download and play the game for 8 hours straight without any errors. As a note I played the beta of the game on the old router without any issues. They changed something in a major way as far as communications/streaming goes since the Beta. Replacing the router solved my problem. I hope it helps others!