Problem

1. PSON: A Scalable Peer-to-Peer File Sharing System Supporting Complex QueriesJyoti Ahuja, Jun-Hong Cui, Shigang Chen and Li Laojyoti@engr.uconn.edu, jcui@cse.uconn.edu, sgchen@cise.ufl.edu, llao@cs.ucla.edu rap movie music comedy pop rock Root jazz games horror Root games movies music rock comedy horror jazz pop rap rap movie music comedy pop rock Root jazz games horror • Problem • Design Goals of P2P File Sharing Systems: Scalability, Efficient routing and Complex query support • Unstructured Systems: Either not scalable or not routing efficient, support complex query • DHT Based Systems: Scalable and routing efficient, but not complex query supportive • Our Objective: To design a scalable and efficient system that supports complex queries • Proposed Solution:Peer-to-Peer Semantic Overlay Network (PSON) • Main Idea • Explore hierarchy and semantics • All files classified according to a given semantic tree, in which a node represents a class of files • Classification of peers: • Super peers: Participate in overlay construction and query routing • Peers: Store file information of other peers, and submit queries to super peers • A logical node is a cluster of physically close peers, with one designated as a super peer • A file directory is assigned to a logical node, logical nodes form an overlay to route queries based on semantics • Overlay construction • Red black treeis used to map semantic hierarchyto an overlay structure of logical nodes • Query routing • Overlay nodes keep pointers to left child, right child, parent, largest and smallest descendants • Performance Evaluation • All delays are measured in terms of logical hops • Used NS-2.27 for simulation and GT-ITM for topology generation Z Query for rock Search Delay Delay Comparison Insertion Delay Deletion Overhead Effect of Semantic Hierarchy