Hybrid Overlay Structure Based on Virtual Node

Current peer-to-peer architectures generally can be grouped into three categories: centralized architectures that utilize central directory servers to process queries, decentralized structured architectures that accurately build an underlying topology to support distributed hash table efficiently, and decentralized unstructured architectures that impose no structure on the topology and typically propagate queries to neighbors for searching. Aiming at integrating the flexibility of unstructured architectures with the regularity of structured architectures, we propose a hybrid overlay structure based on virtual node. Especially, the hybrid architecture utilizes virtual nodes to build a distributed ring with random links. We can use the distributed ring to perform short jumps, and apply random links to long jumps. With our hybrid design, keyword searching, even multi-keyword searching, can be performed efficiently; both popular and rare keywords can be quickly located. Furthermore, our architecture is robust to the change of system scale, and it can work well with low maintenance cost in the dynamic environment.