Imbuing unstructured P2P systems with non-intrusive topology awareness

The random nature of unstructured P2P overlays imbues them with enhanced self-* properties. Most of the algorithms which make searching in unstructured P2P systems scalable, such as dynamic querying and 1-hop replication, rely on the random nature of the overlay to function efficiently. However, they do not take into account the structure of the underlying physical communications network, which is anything but random. Efforts to provide topology awareness to unstructured P2P systems often result to clustered graphs which affect negatively algorithms that rely on random overlays. In this paper, we propose ITA, an algorithm which creates a random overlay of randomly connected neighborhoods providing topology awareness to P2P systems, while at the same time has no negative effect on the self-* properties or the operation of the other P2P algorithms. Using extensive simulations, we demonstrate that ITA reduces communication latency by as much as 50% which is important for P2P users. Furthermore, it reduces by 20% the number of IP network messages which is critical for ISPs carrying the burden of transporting P2P traffic. Finally, ITA is shown to reduce significantly the load imposed on the routers of the IP network layer.