RNet: A hierarchical P2P overlay network for improving locality in a mobile environment

Unstructured peer-to-peer (p2p) systems such as Gnutella use a flooding mechanism to find resources or nodes. These systems waste bandwidth usage and cannot be deployed in a large-scale environment, called scalability problem. To address scalability problem, DHT(distributed hash table)-based p2p systems distribute resources uniformly among nodes. But, they cannot guarantee the shortest physical distance from a requestor to a resource, called locality problem. In a mobile environment, because a user with mobile device moves and requires a service related to user location, locality problem must be addressed. In this paper, we propose a DHT-based hierarchical p2p overlay network, called RNet, with goals of addressing locality problem and providing location-based discovery in a mobile environment. RNet has some advantages such as configuring a dynamic p2p network, reducing discovery time and providing locality-based discovery. We evaluate RNet to show that it can address locality problem efficiently and simulation results demonstrate that RNet improves on discovery time by 30% and routing hops by 25% depending on given environment.