Network Emulation Tools for Modeling Grid Behavior

There is increasing interest in Grids that use compute, storage, and network resources in configurations involving both flexible sharing and tight-coupling. Such usage produces complex dynamics, subject to complex non-linear behavior. We believe that detailed packet level simulation is both possible and necessary forhigh fidelity grid simulations. We present the MicroGrid, a tool set which allows researchers to emulate Grid resources and applications directly. The MicroGrid tools include a scalable network emulatorMaSSF whose design can support emulation thousands of grid resources and application elements.. We demonstrate the MicroGrid, byapplyingthree types of applications: 1) basic parallel applications (NASNAS Parallel Benchmarks), 2) peer to peer applications (Gnutella file sharing), and 3) in a detailed evaluation of GridFTP on the TeraGrid. These studies exploit the packet-level simulation capabilities of MaSSF to expose detailed dynamic communication behavior. In the cases of Gnutella and GridFTP, these dynamic characteristics provide critical insights into how to use and improve the application and resource configurations.