A Structured Peer to Peer File Sharing Model with Non-DHT Searching Algorithm

It is commonly believed that extending structured peer to peer overlays to be capacity-aware will increase maintenance overhead, so it is significant to build a capacity aware protocol that is effective and has low maintenance overhead. Presented in this paper is an effective capacity-aware structured peer to peer protocol—HeteroChord. HeteroChord does not use the traditional method of nodes exchanging routing information to implement capacity awareness, it implements the capacity aware mechanism in a new node’s joining algorithm and updating algorithm. Compared with traditional capacity aware protocols, when a new node joins the system, HeteroChord can calculate the nodes whose routing table should be updated, so the capacity aware mechanism is efficient. The simulation results indicate that the maintenance overhead of HeteroChord is less than that of Chord under churn. Then a non-DHT structured file sharing model called NHFS is constructed based on HeteroChord. In NHFS, The supernodes are connected by super leaf sets, and the file indices are replicated to supernodes, so the queries can be processed simply in supernodes. Super leaf set makes it easy for the queries to traverse the supernodes in NHFS, and the maintenance overhead generated by unidirectional replication mechanism in NHFS is much lower than that generated by bidirectional replication mechanism in HeteroPastry. So the file sharing model NHFS is more reasonable than HeteroPastry.