Recently a friend decided to use an on-line service to backup his 750G raid array. He selected CrashPlan which, among other things, generates a projected completion time. With his existing DSL service it was going to take months, so he signed up for Comcast Internet with a plan that offered "up to" 10 Mbps down and 2 Mbps up. As he put it:
... when I was signing up for Comcast I specifically asked about high-volume on-line backup, and in particular whether it was Ok for me to buy the 2x10 service and run a heavy duty upstream job 24x7 at 1 mbit, and I was reassured that this was OK.To see what happened, look at the "wan-out" statistics in gray above. Comcast came on-line in late March and CrashPlan was configured to use 1 Mbps of the "2 Mbps upstream" bandwidth. This worked for less than two weeks, then Comcast throttled the upstream to less than 600 Kbps. Over the next six weeks, he was further squeezed to ~400 Kbps. Nothing in his house changed during this period, so the data above reflects Comcast's performance. As my friend puts it:
I guess what they meant was "... it's OK to try, since we can rate limit you ... to anything we want, you won't bother us by trying. You won't get your bandwidth either, but that's not our problem. "
Comcast: "Up to X Mbps," but only for occasional use.