Improving Chord Lookup Protocol for P2PSIP-Based Communication Systems

Chord has been suggested as mandatory overlay technology in the future P2PSIP-based communication systems. Chord allows for the available peer/resource lookup in no more than hops, where N is the total number of the peers in the overlay network. However, as a protocol originally designed for background downloading applications, Chord has a few drawbacks when supporting P2PSIP real-time communication systems. These drawbacks are related to ID assignment, the relation between ID and physical location, the routing styles and lack of cache, etc. In this paper, we investigate several approaches that can improve the efficiency of the peer/resource lookup algorithm. After that, we simulate two systems (Chord-based and improved Chord based P2PSIP communication systems) for evaluation. The evaluation includes number of hops, message flows, and practicality from theoretical point of view, and the comparison of the delay in two systems according to the measurement. We get the conclusion that the combination of Bi-Chord, Cache entry record, and Semi-Recursive routing is most suitable for P2PSIP-based communication systems. Finally, we include the conclusions and future work.