DIET (Distributed Interactive Engineering Toolbox) is a set of hierarchical components to design network enabled server (NES) systems. In these systems, clients ask to agents (discovery and scheduling components) to find servers able to solve their problem using some performance metrics and information about the location of data already on the network. Today's NES middleware, in which agents are statically connected and potentially bottlenecks, don't cope with the dynamic and heterogeneous nature of future grid environments. In this paper, we present the design, the implementation and the experimentation of the first architecture extending traditional NES systems with an unstructured peer-to-peer network dynamically connecting distributed agents, to provide to clients an entry point to servers geographically distributed. Our implementation is based on DIET and the JXTA toolbox. Different algorithms have been implemented and experimented over the VTHD network which connects several supercomputers in different research institutes through a high-speed network, showing the scalability of the system.