The impact of content distribution on structured P2P networks in mobile scenarios

Structured Peer-to-Peer (P2P) networks are promising approaches for the use of P2P technologies in resource constrained environments such as mobile communication scenarios. The signaling overhead can be reduced significantly by using a hash function to map the nodes as well as the shared objects onto the same identifier space. Queries need not be flooded through the network but can be routed directly to the responsible node. This node stores references to all peers in the network providing the requested object. The mapping algorithm of the used protocol and the actual content distribution determine the number of object references one node is responsible for. This responsibility affects the maintenance traffic in structured P2P networks, as references (responsibilities) have to be shifted among nodes when a node joins or leaves the overlay. Especially in mobile scenarios a high amount of maintenance traffic heavily influences the system performance. Therefore the content distribution has great impact on the applicability of structured P2P approaches. In this paper, we present the results of our experimental analysis of content distribution in an existing large P2P network and its consequences for the structured P2P system Chord. Based on these results we evaluate the applicability of structured P2P networks in mobile scenarios.