Range queries and load balancing in a hierarchically structured P2P system

Structured Peer-to-Peer (P2P) systems are highly scalable, self-organizing, and support efficient lookups. Furthermore, Distributed Hash Tables (DHTs), due to their features, are used more and more for file-sharing and content distribution applications. However, a major weakness of traditional DHTs is the search for stored content, as data is assigned to nodes based on hash functions, and the very nature of hash tables allows only exact pattern matches. We present Cerco, a solution for the problem of range queries by using the principles of order-preserving DHTs and a hierarchically structured P2P approach. To guarantee an efficient routing and load balancing, Cerco uses a dynamic hierarchy of DHTs by creating subrings on demand and two explicit load balancing strategies. Our evaluation shows that Cerco is able to achieve the goals of supporting range queries, logarithmic-hop routing, and efficient load balancing.