High Level Architecture (HLA)  used for building interactive simulations  connects geographically distributed nodes  time management (for time- and event-driven simulations)  data management (tuple space) GRID - no mechanisms for managing execution according to the dynamically changing conditions of computing resources. - no implementation with dynamic discovery +designed to coordinate resources that are not subject to centralized control +uses standard, open, general-purpose protocols and interfaces +Web Services concept of abstract interfaces allows for modular design - general approach, so no support for interaction Conclusion: we need support for execution of HLA-based distributed interactive simulations in the Grid environment Grid HLA Management System HLA management services –HLA-speaking Service for managing federates –RTIExec Service for managing RTIExec (coordination process in RTI) –Broker for setting up a federation and making migration decisions Broker decision services –Registry for storing location of HLA-speaking services –Infrastructure Monitoring/Benchmarks for checking environment of HLA services Migration support services –Application Monitoring for monitoring performance –Migration Service for performing migration Application Monitoring Service Uses the Grid-enabled OMIS Compliant Monitor (OCM-G) system Supports broker decisions together with Benchmark Services Monitors invocation of particular methods and the time of their invocation (not supported by the Management Object Model) Impact of migration on interactive simulation response time Tests performed on DAS2 Dutch Grid and CYFRONET Interaction Federate at Vrije University, Amsterdam Migration of Simulation Federate from Utrecht to Amsterdam (UvA) RTIExec at CYFRONET Kraków Shows that migration can improve response time HLA-Speaking Service Manages execution of federates on a single site Interfaces federates to the Grid management layer –Migration Library (ML) developed to interface HLA layer with Grid layer Starts, saves and restores federates –ML uses HLA API for saving and restoring internal RTI state –ML functionality includes saving user data Katarzyna Rycerz 1, Marian Bubak 1,2, Maciej Malawski 1, Peter M.A. Sloot 3 1 Institute of Computer Science, AGH, Mickiewicza 30, Kraków, Poland 2 Academic Computer Centre - CYFRONET, AGH, Nawojki 11, Kraków, Poland 3 Faculty of Sciences, Section of Computational Science, University of Amsterdam Kruislaan 403, 1098 SJ Amsterdam, The Netherlands References: 1.Rycerz. K., Baliś, B., Szymacha, R., Bubak, M. and Sloot, P.M.A.: Monitoring of HLA Grid Application Federates with OCM-G, in S.J. Turner; D. Roberts and L. Wilson, editors, Eighth IEEE International Symposium on Distributed Simulation and Real-Time Applications (DS-RT'04), pp IEEE, Budapest, Hungary, October ISBN Rycerz, K., Bubak, M., Malawski, M., and Sloot, P.M.A.: A Framework for HLA--based Interactive Simulations on the Grid, in: Simulation:Transactions of the Society for Modeling and Simulation International. Special Issue: Applications of Parallel and Distributed Simulation in Industry(accepted). This research is partly funded by the European Commission IST Project „CrossGrid”