A Distributed Simulation Backbone for Executing HLA-based - - PDF document

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A Distributed Simulation Backbone for Executing HLA-based Simulation

• ver the Internet
• Y. Xie1, Y.M. Teo1,2, W. Cai3 and S.J. Turner3

1Singapore-MIT Alliance 2Department of Computer Science, National University of Singapore 3School of Computer Engineering, Nanyang Technological University

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Outline

► Distributed simulation, Grid and HLA ► Related work ► Design ► Implementation ► Conclusion & future work

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Distributed Simulation

Provides a way

• f

linking simulation components (federates) of various types at possibly different locations to create a common virtual environment (federation).

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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

• f

federates that exchange information in the form

• f objects and interactions.

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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 ► … … .

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RTI Components

Inter-Process Communications

RtiExec

FedExec Federate Federate

…

libRTI libRTI

Manage multiple federations Manage multiple federates within a federation Provide HLA services to federates

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Cluster/LAN-based HLA Simulation

Simulation Code

• 1. Develop Simulation

(DMSO HLA’s API)

• 2. Execute Simulation

(DMSO HLA Implementation)

LAN (TCP/ IP)

RtiExec

FedExec 1 FedExec n

…

Federate 1 Federate m

…

Federation 1

…

Federation n

Federates … 18 August 2004 IC-SEC 2004 8

Grid-based HLA Simulation

Simulation Code (DMSO HLA API)

• 1. Develop Simulation
• 2. Execute Simulation

Grid

?

Grid Network Grid Network Resource

Client 2

Federate 2

Client 1

Federate 1

Client 3

Federate 3

Resource

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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) ► ..

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Our Approach

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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)

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Architecture of Grid-Enabled Distributed Simulation

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Approach: DMSO + Grid Services

Simulation Code (DMSO HLA API)

• 1. Develop Simulation
• 2. Execute Simulation

Grid Middleware e.g. Globus

Grid Services: deployment, execution, monitoring, load management, fault- tolerance services ...

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Design – Proxy-based Approach

Client 1 Client n

…

Federation 1 Client 1 Client n

…

Federation m Resource RtiExec FedExec1… m Proxies…

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Design

Client

Simulation Code Grid-enabled DMSO HLA API Globus

Resource

Proxy Grid- enabled API LAN Proxies & Federates & RTI DMSO HLA API LAN

Grid Network Grid Services

Grid Services: indexing, discovery, resource management, monitoring services … Globus Globus DMSO API

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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

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HLA-Grid Simulation Service API

► Create RTI ► Create Federation ► Join Federation ► Start federate execution ► Leave execution ► Destroy RTI ► … … … .

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Preliminary Result - Latency

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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.

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Grid Computing Research at Computer Systems Lab, NUS

A framework for supporting the development and execution of large-scale collaborative distributed applications. Core Grid Services

Runtime Support Services Programming Models Testbed Infrastructure

Tools & Environment

• debugging,

monitoring, performance, ..

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

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Thank you

Questions

www.comp.nus.edu.sg/ ~ teoym/ alice.htm