Today the new release of fedora came out. Like any good sensible people, rather than getting slashdotted, they put up some bittorrent releases for people to download. Anyway, so while I was at school today I was getting 400k/s on both the upstream and downstream channels. When I went home I was only getting 8k/s download and about 16k/s upload. Needless to say I was not pleased. It also was quite difficult for me to go look at other stuff on the net. The problem is that my upstream communications were saturating the line and drowning out the necessary packets (including ACKs for downstream data). When I went and I throttled the uplink to 10k/s magically the downstream connection jumped to 80k/s. So the lesson, if you’re on a DSL, throttle the upstream to slightly below your maximum throughput.
The alternative solution is to set up a firewall to prioritize outgoing acks.