ReliableHierarchicalPeer-to-Peer FileSharingSystems

Thispaperpresents anapproach forhierarchical peer-to-peer (P2P)file-sharing systems inthedesign ofthe fault tolerance. Inthehierarchical P2Psystem, peernodesare organized intogroups, andeachgrouphasaspecial peernode called superpeer tomanagetheregular peernodesinthegroup. Withthishierarchical characteristic, theproposed approach utilizes thesuperpeer nodetotolerate thefailures ofthe regular peernodes.Unliketraditional P2P fault-tolerant approaches, theproposedfault-tolerant approachneither replicates thecontents ofthesharing files noraddsredundant overlay connections. Instead, itkeeps track ofthefile retrievals inthesuperpeer nodetosupport thefault tolerance. Thecost oftracking thefile retrievals isfarsmaller thanthecostof replicating thefilecontent. Furthermore, theproposed approach alsoconsiders thefault tolerance ofthesuperpeer nodeby usingtheregistration technique. Theregistration technique alsotakesa smallcostinstoring thefile location information. Finally, theoverall fault-tolerant costofthe proposed approach isanalyzed tocomparewithotherrelated approaches.