TAP : topology aware peer-to-peer network with expanding-area lookup

Abstract

To solve the scalability problem of unstructured P2P(Peer-to-Peer)network, DHT(Distributed Hash Table)-based P2P network is proposed. DHT-based mechanism however does not reflect locality. So that messages are routed inefficiently, which makes long latency of lookup and makes overload in networks. In this paper, we propose a new topology aware Peer-to-Peer(TAP) mechanism which adopts DHT-based approach but solved the problem of inefficient routing of messages. The key idea of TAP is to generate node identifier(NodeId) and object identifier(ObjectId) with hierarchical topology information like country, province and organization. An object is inserted to each level of area and then, nodes lookups the object with expanding area by stages. It leads to fast lookup and download, which is 10 ~ 20 times and 2 times faster than Chord respectively in our experiment. In addition, we can acquire some features like locality, cache-like effect and local broadcast.