A Small World Routing Model for Structured P2P Systems

Peer-to-Peer (P2P) technologies are considered as one of the fundamental technologies for the next generation Internet. P2P systems are classified into unstructured P2P systems or structured P2P systems depending on their topological structure of network. Most structured P2P systems are based on Chord protocol that is designed by using Distributed Hash Tables (DHTs). However, some issues have not still been addressed in structured P2P systems based on DHTs, which include high lookup failure rate, low effective proximity routing, and poor proximity neighbor selection. This paper proposes a Small World Routing Model (SWRM) based on Chord for solving the above issues. The idea of the SWRM comes from the small world characteristic in networks. The SWRM classifies nodes on a network into two classes, which include common nodes and super nodes. The classification principle depends on the status of links with other nodes. Every node in the SWRM can be congregated into different clusters depending on the congregating coefficients and the average shortest hop distance between two chosen nodes. Finally, this paper presents the experimental results of comparing the performance between SWRM and Chord. The experimental results show that it takes fewer lookup hops for the SWRM to find object nodes than Chord, and it takes fewer average lookup successful hops for the SWRM to find object nodes than Chord. Meanwhile, the SWRM has better proximity neighbor selection and is more consistent with the SWC than Chord.