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  1. 1. Design and implementation of Distributed DEVS M&S Framework over Peer-to-Peer Networks Saehoon Cheon Arizona Center for Integrated Modeling and Simulation (ACIMS) Novermber 15th, 2002
  2. 2. Outline <ul><li>Objectives </li></ul><ul><li>Background </li></ul><ul><li>DEVS/P2P </li></ul><ul><li>Conclusion </li></ul><ul><li>Future work </li></ul>
  3. 3. Objectives <ul><li>Introduce distributed simulation issue to DEVS Modeling and Simulation </li></ul><ul><li>Design and implement DEVS over P2P network </li></ul>
  4. 4. Background <ul><li>Peer-to-Peer network </li></ul><ul><li>DEVS Formalism </li></ul><ul><li>JXTA Project </li></ul>
  5. 5. P2P Network <ul><li>No centralized control point </li></ul><ul><li>Direct connection to any other node </li></ul><ul><li>Role as both Server and client </li></ul><ul><li>Napster, Gnutellar, etc. </li></ul>
  6. 6. DEVS Formalism <ul><li>Set theory based system specification formalism </li></ul><ul><li>Atomic model : lowest level model, contains structural dynamics </li></ul><ul><li>Coupled model: composed of one or more atomic and/or coupled model </li></ul><ul><li>-> hierarchical construction </li></ul><ul><li>Basic Parallel DEVS Model: </li></ul><ul><ul><li>M =  X,Y,S,  int ,  ext ,  con ,  , ta  X: set of input events Y: set of output events S: set of states  int : internal transition function  ext : external transition function </li></ul></ul><ul><ul><li> con : confluent function  : output function ta: time advance function </li></ul></ul><ul><li>Time base is logical time </li></ul>
  7. 7. Coupled model and hierarchical structure
  8. 8. Coordinator and simulator
  9. 9. JXTA Project <ul><li>An open network technology developed by Sun Inc. to support P2P computing on any platform, anywhere </li></ul><ul><li>Basic Concept </li></ul><ul><ul><li>Peer – network device that implements the JXTA protocol </li></ul></ul><ul><ul><li>Peer Groups- collection of cooperating peers providing a common set of services </li></ul></ul><ul><ul><li>Pipe – communication channel between peers </li></ul></ul><ul><ul><li>Advertisement – language-neutral metadata structure represented as XML documents </li></ul></ul><ul><li>Fully open source at </li></ul>
  10. 10. JXTA Project: JXTA Search Network Architecture
  11. 11. DEVS/P2P <ul><li>Support </li></ul><ul><ul><li>Hierarchical model partitioning </li></ul></ul><ul><ul><li>Automatic coupling restructuring </li></ul></ul><ul><ul><li>Automatic model deployment </li></ul></ul><ul><ul><li>Distributed/parallel/local simulation </li></ul></ul>
  12. 12. Scalable DEVS: Layered Architecture Network Infrastructure Network Middleware Scalable DEVS Interface DEVS Application JXTA Globus RTI Visibroker P2P Grid HLA CORBA modeling simulation
  13. 13. DEVS/P2P <ul><li>Interface for DEVS implementation over P2P Network </li></ul><ul><li>Adopt JXTA as P2P infrastructure </li></ul>
  14. 14. DEVS/P2P: Overall Architecture
  15. 15. DEVS/P2P : Model Deployment
  16. 16. DEVS/P2P: Communication between simulators
  17. 17. DEVS/P2P: (XML) Data Format & Example <ul><li><!DOCTYPE jxta:DEVSAdvertisement> </li></ul><ul><li><jxta:DEVSAdvertisement xmlns:jxta=&quot;;> </li></ul><ul><li><DEVS-P2P-Protocol> [version] </ DEVS-P2P-Protocol> </li></ul><ul><li><Protocol–Group> [protocol group] </ Protocol–Group > </li></ul><ul><li><Type> [protocol-associated type] </Type> </li></ul><ul><li><Source> [source id of a msg] </Source> </li></ul><ul><li><Target> [target id of a msg] </Target> </li></ul><ul><li><Time stamp> [ time stamp of a msg ] </Time stamp> </li></ul><ul><li><Object> [embedded devs object] </Object> </li></ul><ul><li></DEVSAdvertisement> </li></ul>
  18. 18. DEVS/P2P: DEVS msg to JXTA msg
  19. 19. DEVS/P2P: Mapping DEVS ports into pipes
  20. 20. DEVS/P2P: Module Spec Advertisement <ul><li><?xml version=&quot;1.0&quot;?> </li></ul><ul><li><!DOCTYPE jxta:MSA> </li></ul><ul><li><jxta:MSA xmlns:jxta=&quot;;> </li></ul><ul><li><MSID> </li></ul><ul><li>urn:jxta:uuid-DF8BC25CBFAE4E5A808A91B8985CB09FAC9275FF33114E4C93F38C4AD27263E706 </li></ul><ul><li></MSID> </li></ul><ul><li><Name> JXTASPEC:DEVS-INPUTPORT:gpt:Proc-0.Protocol-In </Name> </li></ul><ul><li><Crtr> ACIMS </Crtr> </li></ul><ul><li><SURI> </SURI> </li></ul><ul><li><Vers> Version 1.0 </Vers> </li></ul><ul><li>// Embedded PipeAdvertisement </li></ul><ul><li></jxta:MSA> </li></ul>
  21. 21. DEVS/P2P: Pipe Advertisement <ul><li><!DOCTYPE jxta:PipeAdvertisement> </li></ul><ul><li><jxta:PipeAdvertisement xmlns:jxta=&quot;;> </li></ul><ul><li> <Id> </li></ul><ul><li> urn:jxta:uuid-59616261646162614E50472050325033 </li></ul><ul><li>4B02E6FA9 D054ECBA9BCB2C223E21C6204 </li></ul><ul><li> </Id> </li></ul><ul><li> <Type> </li></ul><ul><li>JxtaPropagate </li></ul><ul><li> </Type> </li></ul><ul><li> <Name> </li></ul><ul><li>gpt:Transd.Protocol-In </li></ul><ul><li> </Name> </li></ul><ul><li></jxta:PipeAdvertisement> </li></ul>
  22. 22. DEVS/P2P: communication without coordinator
  23. 23. DEVS/P2P: Simulation Protocol
  24. 24. DEVS/P2P: Simulation Protocol (cont’)
  25. 25. Demonstration: gpt model
  26. 26. Demonstration: (1) run activator
  27. 27. Demonstration: (2) run partitioner and send payload to the peer
  28. 28. Demonstration: (3) extract port information & establish IO Port connection
  29. 29. Demonstration: (3) start simulation(Peer)
  30. 30. Conclusion <ul><li>Introduced DEVS M&S Framework </li></ul><ul><li>Developed DEVS over JXTA environment </li></ul><ul><li>Introduced the possibility of DEVS simulation without coordinator </li></ul><ul><li>Showed the distributed simulation over middleware for data communication </li></ul>
  31. 31. Future work <ul><li>More care of DEVS/P2P protocol </li></ul><ul><li>Develop Coupled model simulator </li></ul><ul><li>Develop reliable pipe for DEVS/P2P </li></ul><ul><li>Design generic interface of DEVS Layer for various distributed network middlewares </li></ul>
  32. 32. Question?
  33. 33. Backup: Hierarchical Model Partitioning <ul><ul><li>Map a hierarchical model into a set of partitions </li></ul></ul><ul><ul><li>Maintain hierarchical structure as much as possible </li></ul></ul>
  34. 34. Backup: : Hierarchical Model Partitioning : Example
  35. 35. Hierarchical Model partitioning (Cont’)
  36. 36. Parallel and distributed DEVS simulation protocol
  37. 37. Parallel and distributed DEVS simulation protocol(cont.)
  38. 38. Peer discovery
  39. 39. Peer discovery(2)
  40. 40. Peer resolver protocol
  41. 41. Pipe binding protocol
  42. 42. Pipe information protocol
  43. 43. Background: Parallel simulation and Distributed Simulation <ul><li>Distributed simulation: </li></ul><ul><ul><li>The simulation technology that enables a simulation program to be executed in a geographically dispersed network system </li></ul></ul><ul><li>Parallel simulation: </li></ul><ul><ul><li>The simulation technology that can execute the simulation concurrently in the multiprocessor architecture </li></ul></ul>