18-Aug-04 A Distributed Simulation Backbone for Executing HLA-based Simulation over the Internet Y. Xie 1 , Y.M. Teo 1,2 , W. Cai 3 and S.J. Turner 3 1 Singapore-MIT Alliance 2 Department of Computer Science, National University of Singapore 3 School of Computer Engineering, Nanyang Technological University Outline ► Distributed simulation, Grid and HLA ► Related work ► Design ► Implementation ► Conclusion & future work 18 August 2004 IC-SEC 2004 2 1
18-Aug-04 Distributed Simulation Provides a way of linking simulation components (federates) of various types at possibly different locations to create a common virtual environment (federation). 18 August 2004 IC-SEC 2004 3 HLA (High Level Architecture) ► The High Level Architecture (HLA) is a general purpose architecture for simulation reuse and interoperability. ► The HLA was developed under the leadership of the Defense Modeling and Simulation Office (DMSO) ► The HLA was approved as IEEE Standard 1516 - in September 2000. ► Terminology: Federations are comprised of federates that exchange information in the form of objects and interactions. 18 August 2004 IC-SEC 2004 4 2
18-Aug-04 RTI (Run-Time Infrastructure) ► Implements the interface specification and provides services for simulation systems. ► RTI services: ► Separate simulation and communication ► Facilitate construction and destruction of federations ► Support object declaration and management ► Assist with federation time management ► Provide efficient communication to logical group of federates ► … … . 18 August 2004 IC-SEC 2004 5 RTI Components Manage multiple Manage federates within a Provide HLA multiple federation services to federations federates Federate Federate … RtiExec FedExec libRTI libRTI Inter-Process Communications 18 August 2004 IC-SEC 2004 6 3
18-Aug-04 Cluster/LAN-based HLA Simulation 2. Execute Simulation (DMSO HLA Implementation) 1. Develop Simulation (DMSO HLA’s API) RtiExec FedExec 1 FedExec n … Simulation Code LAN (TCP/ IP) … … Federate 1 Federate m Federates … Federation 1 Federation n 18 August 2004 IC-SEC 2004 7 Grid-based HLA Simulation 2. Execute Simulation Resource 1. Develop Simulation Federate 3 Client 3 Simulation Code (DMSO HLA API) Grid Network Federate 2 Grid Network Client 2 Resource ? Federate 1 Grid Client 1 18 August 2004 IC-SEC 2004 8 4
18-Aug-04 Related Work ► XMSF (Extensible Modeling and Simulation Framework) – based on web services ► Re-implement all RTI services ► Extend RTI software as backbone over WAN ► Proxy-based approach – wrap RTI services as grid services (this paper) ► .. 18 August 2004 IC-SEC 2004 9 Our Approach 18 August 2004 IC-SEC 2004 10 5
18-Aug-04 Grid-Enabled Distributed Simulation Main objectives: • To develop a framework for executing large-scale distributed simulations over Grid environments • To develop grid services, e.g., resource monitoring and management services, required by the framework • To develop runtime library to support plug-in HLA- based distributed simulations in the framework • To develop applications to demonstrate the feasibility and advantages of the framework HLA (High Level Architecture) for distributed simulation, IEEE Standard 1516, Sep 2000) 18 August 2004 IC-SEC 2004 11 Architecture of Grid-Enabled Distributed Simulation 18 August 2004 IC-SEC 2004 12 6
18-Aug-04 Approach: DMSO + Grid Services 2. Execute Simulation 1. Develop Simulation Grid Services: deployment, execution, monitoring, load Simulation Code management, fault- (DMSO HLA API) tolerance services ... Grid Middleware e.g. Globus 18 August 2004 IC-SEC 2004 13 Design – Proxy-based Approach Client 1 Client 1 Grid Network Grid Network … … Client n Client n Resource RtiExec Federation 1 Federation m FedExec1… m Proxies… 18 August 2004 IC-SEC 2004 14 7
18-Aug-04 Design Grid Services: indexing, discovery, resource Grid management, monitoring services … Services Globus Proxy Simulation Code Proxies & Federates & RTI Grid- DMSO Grid-enabled enabled API API DMSO HLA API DMSO HLA API Globus LAN Globus LAN Grid Client Resource Network 18 August 2004 IC-SEC 2004 15 Why Proxy-based Approach ► separation of client federate & RTI ► Ensures the security of the simulation model ► reduced (no) firewall issue ► Provides user transparency and simulator reusability ► Easy migration of federates that sit on client and also migration/ distribution of simulation backbone ► Interoperability based on standard interface ► Backbone implemented in Java – supports interoperability of heterogeneous platforms ► … … … .. Disadvantage: Overhead of communication 18 August 2004 IC-SEC 2004 16 8
18-Aug-04 HLA-Grid Simulation Service API ► Create RTI ► Create Federation ► Join Federation ► Start federate execution ► Leave execution ► Destroy RTI ► … … … . 18 August 2004 IC-SEC 2004 17 Preliminary Result - Latency 18 August 2004 IC-SEC 2004 18 9
18-Aug-04 Conclusion & Future Work ► Design infrastructure to enable distributed simulation using HLA on Grid ► Implement prototype based on Globus Toolkit version 3 ► Performance analysis – ongoing NTU-NUS- Birmingham University (UK) ► research issues - federation dynamic naming, federate migration, fault tolerance, etc. 18 August 2004 IC-SEC 2004 19 Grid Computing Research at Computer Systems Lab, NUS A framework for supporting the development and execution of large-scale collaborative distributed applications. Tools & Programming Models Testbed Environment Infrastructure - debugging, monitoring, Runtime Support Services performance, .. Core Grid Services 1. GRAPES (Grid Application Programming Environments & Systems): grid memory abstraction models, code optimizations, mobile code safety, grid application performance, etc. 2 . GES3 : Grid-Enabled Self- Organizing and Scalable Services 3. Fault-tolerant Consensus in Distributed Systems 4. A Framework for Large-Scale Grid-Enabled Distributed Simulation 18 August 2004 IC-SEC 2004 20 10
18-Aug-04 Thank you Questions www.comp.nus.edu.sg/ ~ teoym/ alice.htm 18 August 2004 IC-SEC 2004 21 11
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