Well, I figured out the ping plot, even though I still can't post it. At hop 4 in Richmond, I'm getting between 30% and 75% packet loss. I suspect this may explain why I keep getting shot down within 5 seconds instead of the usual 10 or 15. The IP on that hop is 68.86.172.222. Is this the information I give Comcast to see if they can do anything about it?