Key Technology Research And Implementation Of The High-performance Multi-source Downloading System

With the rapid development of the Internet, various network applications are emergingand expanding, making it more convenient for people to exchange information.File sharing,particularly network download techniques, are a common form of network techniques thatserve people’s need of communication. Such techniques facilitate the flow of informationamong people. Nowadays, people design and implement various download software based ondifferent download protocols. The download speed and quality grow substantially. From thetraditional C/S pattern based on HTTP/FTP to the P2P pattern using BitTorrent/eMuleprotocol, and the emergence of the P2SP pattern which combines the advantage of both theC/S pattern and the P2P pattern, file sharing techniques are becoming mature.This thesis first analyzes the download process of some typical P2SP software,pinpointing why P2SP software can accelerate via multi-source download.One degeneratesituation in the P2SP download process is indicated based on these analyses.Local resourcesignature isbrought in to deal with the degeneration. By analyzing the relationship betweenlocal resource signature and resource signature, a local resource signature based pre-judgmentapproach to solve the degenerate problem is proposed.Then the relationship between effective resource signature and resource signatureisdiscussed extensively.It can be inferred that effective resource signaturesare distributed inthebinary Trie in a dense on top and sparse at bottom mannerthrough the expected number ofnodes in each level of the binary Trie. Based on this property, aresource searching algorithmbased onthe optimal Trie is proposed to handlethe search of resource signature.An implementation that supports high performance multi-source download is proposed atlast.Key techniques include the communication between P2SP clients and resource indexingservers, multi-thread download supporting multiple protocols, the compatibility with P2Pdownload and the storage of key information at the resource indexing servers.