Alexei Roudnev wrote:
Interesting. Are there any p2P systems which optimize traffic by localizyng it, when possible?
Most p2p applications keep the connections which provide data at better speed and drop the ones which don´t. The effectiveness of this criteria varies from application to application. As far as I´m aware there are no applications that look at the locality of the data. There are many different approaches to increase the locality by modifying the traffic in various ways, from simple ones like ours which allows you to mark packets or announce prefixes over BGP4 for your network to police the p2p heavy remote-and-expensive prefixes to more extensive ones where the actual packet contents are modified to steer the payload traffic. Depending on the aggressiveness of the applications, this works differently. DirectConnect and Bittorrent are very aggressive on adapting their network configuration while eDonkey or FastTrack seem to be more relaxed. Obviously content availability also plays a big factor here since it´s hard to download from somewhere which does not yet have the bits. As far as I know no p2p networks do larger scale topology calculations but all base their activity on local selfish host behavior. Which is probably right on the mark 90% of the time anyway. Pete