It would take a little doing, but how about this?
Ascertain what your download speed is, with one of the standard speed tests.
Let's say the download speed tests say that the connection is running at 10 mbps.
Now open up multiple browser windows with a broadband stream. The Indiana University opera streaming page at »music.indiana.edu/iumusiclive/streaming/
will do nicely, since their HD streams run at 3 mbps. So open three of those windows, and you will have used up 9 mbps of your available bandwidth, and you will only have 1 mbps of bandwidth left.
Now pull up one of those live TV streams which WWI TV offers at »wwitv.com/menu_left.htm
. Pick one that runs almost 1 mbps. There's a good Czech video stream that runs almost .9 mbps at »mms
Okay, now that you've got your download path completely clogged, see what happens with your upload. If you seem to have the full 1mbps available to you, then there are really two lanes. If the upload has been impacted by the maxing out of the download, then there's really only one lane.
And that's exactly what I just did.
And there are definitely two lanes, because, even as the stream playback began to falter and buffer because of the congestion, the upload speed just kept on sailing away at a constant 900 kbps.
So you are right; thank you!