This seems like a pretty cool idea. They essentially bolt on a new congestion control strategy onto TCP. It only requires server side changes and doesn't need any changes to either the receivers or the routers or the packet headers. Instead of taking predefined actions when events like packet loss occurs it uses the events as a feedback mechanism into its control algorithm which attempts to optimize a plugable utility function. Very cool. I would like to try this out my laptop but it looks like it isn't quite ready for that yet! (the prototype is a user space implementation) (you can run their experiments if you have a fedora 15 box. There are some issues on ubuntu)