Design and implementation of Distributed DEVS M

1
Design and implementation of Distributed DEVS MS
Framework over Peer-to-Peer Networks

• Saehoon Cheon

Novermber 15th, 2002
Arizona Center for Integrated Modeling and
Simulation (ACIMS)
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Outline

• Objectives
• Background
• DEVS/P2P
• Conclusion
• Future work

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Objectives

• Introduce distributed simulation issue to DEVS
  Modeling and Simulation
• Design and implement DEVS over P2P network

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Background

• Peer-to-Peer network
• DEVS Formalism
• JXTA Project

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P2P Network

• No centralized control point
• Direct connection to any other node
• Role as both Server and client
• Napster, Gnutellar, etc.

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DEVS Formalism

• Basic Parallel DEVS Model
• M ltX,Y,S,dint ,dext , dcon , l , tagtX set of
  input eventsY set of output eventsS set of
  statesdint internal transition functiondext
  external transition function
• dcon confluent functionl output
  functionta time advance function
• Time base is logical time

• Set theory based system specification formalism
• Atomic model lowest level model, contains
  structural dynamics
• Coupled model composed of one or more atomic
  and/or coupled model
• -gt hierarchical construction

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Coupled model and hierarchical structure
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Coordinator and simulator
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JXTA Project

• An open network technology developed by Sun Inc.
  to support P2P computing on any platform,
  anywhere
• Basic Concept
• Peer network device that implements the JXTA
  protocol
• Peer Groups- collection of cooperating peers
  providing a common set of services
• Pipe communication channel between peers
• Advertisement language-neutral metadata
  structure represented as XML documents
• Fully open source at http//www.jxta.org

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JXTA ProjectJXTA Search Network Architecture
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DEVS/P2P

• Support
• Hierarchical model partitioning
• Automatic coupling restructuring
• Automatic model deployment
• Distributed/parallel/local simulation

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Scalable DEVSLayered Architecture
Application
DEVS
modeling
simulation
Scalable DEVS Interface
Network Middleware
JXTA
Globus
RTI
Visibroker
Network Infrastructure
P2P
Grid
HLA
CORBA
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DEVS/P2P

• Interface for DEVS implementation over P2P
  Network
• Adopt JXTA as P2P infrastructure

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DEVS/P2POverall Architecture
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DEVS/P2P Model Deployment
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DEVS/P2PCommunication between simulators
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DEVS/P2P(XML) Data Format Example

• lt!DOCTYPE jxtaDEVSAdvertisementgt
• ltjxtaDEVSAdvertisement xmlnsjxta"http//devs.or
  g"gt
• ltDEVS-P2P-Protocolgt version lt/
  DEVS-P2P-Protocolgt
• ltProtocolGroupgt protocol group lt/
  ProtocolGroup gt
• ltTypegt protocol-associated type lt/Typegt
• ltSourcegt source id of a msg lt/Sourcegt
• ltTargetgt target id of a msg lt/Targetgt
• ltTime stampgt time stamp of a msg lt/Time stampgt
• ltObjectgt embedded devs object lt/Objectgt
• lt/DEVSAdvertisementgt

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DEVS/P2PDEVS msg to JXTA msg
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DEVS/P2PMapping DEVS ports into pipes
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DEVS/P2P Module Spec Advertisement

• lt?xml version"1.0"?gt
• lt!DOCTYPE jxtaMSAgt
• ltjxtaMSA xmlnsjxta"http//jxta.org"gt
• ltMSIDgt
• urnjxtauuid-DF8BC25CBFAE4E5A808A91B8985CB09FAC
  9275FF33114E4C93F38C4AD27263E706
• lt/MSIDgt
• ltNamegt JXTASPECDEVS-INPUTPORTgptProc-0.Protoc
  ol-In lt/Namegt
• ltCrtrgt ACIMS lt/Crtrgt
• ltSURIgt http//www.acims.arizona.edu/gptProc-0.P
  rotocol-In lt/SURIgt
• ltVersgt Version 1.0 lt/Versgt
• // Embedded PipeAdvertisement
• lt/jxtaMSAgt

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DEVS/P2PPipe Advertisement

• lt!DOCTYPE jxtaPipeAdvertisementgt
• ltjxtaPipeAdvertisement xmlnsjxta"http//jxta.or
  g"gt
• ltIdgt
• urnjxtauuid-59616261646162614E504720503250
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• 4B02E6FA9 D054ECBA9BCB2C223E21C6204
• lt/Idgt
• ltTypegt
• JxtaPropagate
• lt/Typegt
• ltNamegt
• gptTransd.Protocol-In
• lt/Namegt
• lt/jxtaPipeAdvertisementgt

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DEVS/P2P communication without coordinator
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DEVS/P2PSimulation Protocol
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DEVS/P2PSimulation Protocol (cont)

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Demonstrationgpt model
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Demonstration(1) run activator
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Demonstration(2) run partitioner and send
payload to the peer
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Demonstration(3) extract port information
establish IO Port connection
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Demonstration(3) start simulation(Peer)
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Conclusion

• Introduced DEVS MS Framework
• Developed DEVS over JXTA environment
• Introduced the possibility of DEVS simulation
  without coordinator
• Showed the distributed simulation over middleware
  for data communication

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Future work

• More care of DEVS/P2P protocol
• Develop Coupled model simulator
• Develop reliable pipe for DEVS/P2P
• Design generic interface of DEVS Layer for
  various distributed network middlewares

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Question?
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BackupHierarchical Model Partitioning

• Map a hierarchical model into a set of partitions
  
• Maintain hierarchical structure as much as
  possible

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Backup Hierarchical Model Partitioning
Example
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Hierarchical Model partitioning (Cont)
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Parallel and distributed DEVS simulation protocol
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Parallel and distributed DEVS simulation
protocol(cont.)
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Peer discovery
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Peer discovery(2)
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Peer resolver protocol
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Pipe binding protocol
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Pipe information protocol
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BackgroundParallel simulation and Distributed
Simulation

• Distributed simulation
• The simulation technology that enables a
  simulation program to be executed in a
  geographically dispersed network system
• Parallel simulation
• The simulation technology that can execute the
  simulation concurrently in the multiprocessor
  architecture