Evaluation Platform for Large Scale P2P Mobile Ad-hoc Networks

Many innovative P2P algorithms designed for mobile ad-hoc networks (MANETs) have been designed to scale smoothly when handling a very large number of nodes and transmissions. To cope with the complexity of software development for large-scale MANETs, simulations are widely used instead because hardware implementations are too costly. Simulations are very well suited to testing and evaluating concepts, but when implementing algorithms for testing on target systems, unexpected problems can often surface. Thus, once simulations have provided satisfactory results, emulation is a more desirable approach for detecting and handling unexpected behavior before committing to large-scale deployment. In particular, given that large P2P testbeds require a large number of devices spread over a prohibitive space and are limited by complex programming models, the authors are featuring a Java-based emulator called Freemote. To demonstrate some of the practical advantages of combining simulation and emulation, Freemote makes it possible to integrate real and emulated nodes, and the real nodes (JMotes) run exactly the same Java programs as emulated nodes. Since the JMotes are still not very widely used, the Freemote emulator and JMotes have been designed to be compatible with the more popular Berkeley’s motes. Furthermore, remarkable visualization and development tools have been implemented to undertake large-scale emulation of ad-hoc algorithms, featuring a high level of realism. Freemote has been tested in emulations for up to 10,000 nodes, distributed over ten computers (refer to a preceding chapter of this book “P2P Information Lookup, Collection and Distribution in Mobile Ad-Hoc Network” for a test application running DHT algorithms). In this chapter, the authors present the Freemote platform along with the results of a brief comparison of emulation and simulation experiments.