In the case of Debian Aptosid mirrors i am having problem with, i have bein pinging an unrelated site, just to keep the connection alive.
The last two days i did both updates and upgrades while pinging the actual hubs - the ones i could see through traceroute. What do you know - quite a success. The speed so far keeps quite constant and close to normal.
So, the moral, at this stage, until they scratch their buts again, is - if you notice throttling on file downloads (i can't say anything of uploads, and torrent therefore) - try pinging at the same time the hubs.
By the way, two days later, my post with documentation of the TCP disruptions in the debian community is being "moderated". Way to go. With all the activity on this bustling busy forum, it is akin to showing up with your chips and beer on your favorite abandoned playground to find all those guys (and gals) in nice uniforms wearing latex gloves, with metal detectors and anal probes at hand.
Spread them, now!