However, the simulations indicates that doing them in sequence takes less total time that doing them more or less at the same time. So, we need a better model for another set of simulations. There is not much of a difference between 1 and 4 simultaneous connections, but the smaller window sizes yield faster transfers. Persistent connections don't seem to affect the speed. Using small windows and small number of connections is still the big win.
Persistent connections do seem to help when there is more packet loss.
It also turns out that high levels of loss are needed to keep queue lengths from growing in the wide area network. Using a proxy is a big win for everyone even with low hit-rate on the cache. Proxying is good for everyone. Rob Libshultz experimented with proxy for dialup. However, his users still want to go direct over using the proxy.