A Low-Overhead Structure Maintenance Approach for Building Robust Structured P2P Systems

Structured peer-to-peer (P2P) systems have been recognized as an efficient approach to solve the resource discovery problem in large-scale dynamic distributed systems. The efficiency of structured P2P resource discovery approaches is attributed to their structured property. However, system dynamism caused by changes in the system membership, i.e., nodes that join or leave the system or simply fail, perturbs the structure of the system and endangers the expected correctness and efficiency of the resource discovery mechanism. In this paper we propose an event-oriented low-overhead approach to the maintenance of the structure of such systems in the face of node perturbations, by updating only those parts of the system state that are affected by perturbations, upon detection of a node membership change. This way, system robustness is improved too because system structure is kept up-to-date upon each perturbation. The proposed approach is general and can be applied to any structured P2P system. However, we suffice to show how it can be applied to the Chord system to demonstrate its applicability. We show experimentally that our proposed approach has less communication overhead than Chord and that it keeps the system up-to-date and consistent in its lifetime rather than in some periods as in Chord.