Performance Enhancement in Hierarchical Peer-to-Peer Systems

Increased popularity of decentralized peer-to-peer (P2P) architecture comes with several challenges, like how to handle efficient lookup and query routing, frequent joining and leaving of nodes and scalability problem. Several key based deterministic routing approaches in a structured P2P networks have been proposed to overcome with these problems. Still, problems become worse if nodes are heterogenous in processing speed, power, stability and storage capability. To bridge the heterogeneity, we propose a 2-tier hierarchical distributed hash table (DHT) in which nodes are classified into three categories: temporary, stable and fully stable nodes. We have achieved intra-group lookup and query routing in O(log(|G_j|)) steps, where |G_j| is the number of (super)peers in destination group G_j, while inter-group lookup in O(1) steps. We have also saved at least 66.67% messages in repairing the routing table due to frequent joining and leaving of nodes in average case.