After a week of massive downloads I found that my Telstra Bigpond Cable connection had become shaped. I still had about five gigabytes to download when I my connection was shaped down to 56.6K.

I called the Telstra Bigpond account department and they told me that they are allowed to release the shaping one time during the contract period. It took about ten minutes for the shaping to be released and my traffic returned to normal. The release works until the end of the month.

If you're a Bigpond cable user and you get shaped early in the month then consider calling the accounts department and getting the restriction removed.