Song Haibin wrote: >> "On the other hand, P2P systems not adopting the tit-for-tat approach >> (e.g. the eDonkey network) should not be damaged by locality-based" >> It is not clear to me. Peer selection (tit-for-tat like choking algo in >> BT) is not the only one factor of efficiency, there is also piece >> diversity. >> Edonkey/emule also use rarest first (but a less efficient peer selection >> algorithm). Therefore, as locality adversely impact >> piece diversity, my bet is that Edonkey/emule will suffer from locality. >> > > What do you mean with "less efficient" by saying "Edonkey/emule also use > rarest first (but a less efficient peer selection algorithm)"? >
The peer selection algorithm of a P2P protocol is a tradeoff between maximizing the efficiency (in terms of download completion time, or upload utilization of leechers) and fostering persistency of seeds (and of the torrent). BT with its choking algorithm clearly fosters the efficiency of the torrent. The peer selection algorithm of Emule fosters persistency. You are served by a peer when you are the first one in its waiting queue. You place is the queue is mainly of function of the time you spent in the queue and your upload contribution. I believe this upload contribution and the rarest first piece selection was added to emule based on BT experience in order to improve its efficiency, but the main focus of emule is still to keep peers as long as possible in the swarm in order to improve the persistency of contents. Regards, Arnaud. _______________________________________________ p2p-hackers mailing list p2p-hackers@lists.zooko.com http://lists.zooko.com/mailman/listinfo/p2p-hackers
