[Paper presented at:] Second International Conference on Advances in P2P Systems. AP2PS 2010. October 25-30, Florence (Italy)In this paper, we report on the results of experiments with an implementation of H-P2PSIP, which allows the exchange of information among different DHTs (Distributed Hash Tables) making use of a hierarchical architecture. This paper validates our previous H-P2PSIP proposal in an environment with a real TCP/IP stack close to a real scenario. The results show how the benefits of this real H-P2PSIP implementation in terms of routing performance (number of hops), delay and routing state (number of routing entries) are better than a flat DHT overlay network and how the exchange of information among different DHT overlay ne...