Software Technologies for the Interoperability, Reusability and Adaptability of Distributed Simulators

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Conference Presentation, Euro-SIW 2007

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Software Technologies for the Interoperability, Reusability and Adaptability of Distributed Simulators

  1. 1. 2007 Euro Simulation Interoperability Workshop Software Technologies for the Interoperability, Reusability and Adaptability of Distributed Simulators Presented by Daniele Gianni Phd Candidate A. D’Ambrogio, D. Gianni, and G. Iazeolla Dipartimento di Informatica, Sistemi e Produzione University of Rome “TorVergata”
  2. 2. 2007 Euro Simulation Interoperability Workshop Overview • Background • HLA • Problems in the design and development of DES distributed simulators • Proposed solutions • CORBA-HLA • SimJ • Preliminary experiments
  3. 3. 2007 Euro Simulation Interoperability Workshop High Level Architecture (HLA) • Standard DMSO (1995) • Facility OMG for Distributed Simulation (1998) • Standard IEEE 1516 (2000) • Four documents • Objective: to improve distributed simulation SW reusability and interoperability
  4. 4. 2007 Euro Simulation Interoperability Workshop HLA simulations main components • RTI: distributed simulation middleware • Federate: an instance of a simulator • Federation: a set of instances of simulators running in the same distributed simulation
  5. 5. 2007 Euro Simulation Interoperability Workshop RTI – Federate communications Federate RTI Ambassador Federate Ambassador Runtime Infrastructure (RTI)
  6. 6. 2007 Euro Simulation Interoperability Workshop What HLA offers • A general framework to develop distributed simulators (military, discret events, Internet gaming, etc.). • A set of simulation-oriented services to: • Manage the federation (creation, destroying, synchronization, etc.) • Manage the simulation time (constrained or constraining) • Exchange data (objects, interactions, etc.) • Etc.
  7. 7. 2007 Euro Simulation Interoperability Workshop What HLA does not offer • Internal event management • Synchronization logic between local and distributed environments • Services for specific simulation paradigms (continuous, discrete, process interaction, event scheduling, etc.)
  8. 8. 2007 Euro Simulation Interoperability Workshop Development Effort (When building new DES federates) • Acquire HLA Know-how (una tantum) • Adapt to a different conceptual framework • Develop software components for: • Synchronization and communication among local components • Synchronization and communication between local – distributed environments Furthermore, simulation components depend on: • Distributed simulation technology • Execution environment
  9. 9. 2007 Euro Simulation Interoperability Workshop Development Effort (When reusing existing federates) • Adapt to a different non-interoperable RTI • Adapt exchanged data format, etc.
  10. 10. 2007 Euro Simulation Interoperability Workshop Problem How to reduce the design and development effort gap between local and distributed simulators i.e.: How to reduce: HLA know-how and development effort By increasing: • Interoperability, • Reusability, • Adaptability.
  11. 11. 2007 Euro Simulation Interoperability Workshop Interoperability in HLA Is: • Running Java, C++ and ADA95 federates together in the same federation • Running, together, federates on etherogeneous SW and HW platforms Thus NOT: • Inter-RTI interoperability
  12. 12. 2007 Euro Simulation Interoperability Workshop Reusability in HLA Is: • Reuse of a federate in a new federation • Reuse of the RTI SW across simulation domains and applications Thus NOT reuse of components for: • Synchronization and communication • Logical Process (LP) within each federate
  13. 13. 2007 Euro Simulation Interoperability Workshop Adaptability in HLA Not a HLA objective HLA provides generic services for distributed simulation, e.g.: • Data update only upon “significant” variation of values • Event Sending an Receiving in TSO or RO • Etc. Adapting HLA to DES  modelling limitations
  14. 14. 2007 Euro Simulation Interoperability Workshop Proposed solutions We introduce two technologies: • CORBA-HLA • Improves interoperability and reusability • SimJ • Improves reusability and adaptability
  15. 15. 2007 Euro Simulation Interoperability Workshop CORBA-HLA
  16. 16. 2007 Euro Simulation Interoperability Workshop CORBA Architecture IDL Stub IDL Skeleton Object Request Broker Request ClientClient Object Implementation Object Implementation IDL Stub IDL Skeleton Object Request Broker Request ClientClient Object Implementation Object Implementation (Server)
  17. 17. 2007 Euro Simulation Interoperability Workshop Communication between RTI and Federate Federate RTI Ambassador Federate Ambassador Runtime Infrastructure (RTI)
  18. 18. 2007 Euro Simulation Interoperability Workshop Improving interoperability through … Standard, open and highly interoperable protocols to vehicle HLA service calls and data Thus: Federates using CORBA-HLA can switch to any HLA implementation that exposes its services through IDL interfaces, i.e. achieves technical interoperability [Tolk] [Tolk] A. Tolk, J. Muguira, “The Level of Conceptual Interoperability”, The 2003 Fall Simulation Interoperability Workshop, 03F-SIW-07
  19. 19. 2007 Euro Simulation Interoperability Workshop Improving reusability through … Interoperability: federates can be reused across several RTIs
  20. 20. 2007 Euro Simulation Interoperability Workshop CORBA-HLA Architecture (hw/sw view) Host 2 Host n Host 1 CORBA-RTI Server ORB RTI Implementation Key HLA Service request / response flow Federate ... Local RTI Local RTI Local RTI RTI Executive Local RTI CORBA-HLA (either Local RTI or RTI Executive) Pitch Local RTI
  21. 21. 2007 Euro Simulation Interoperability Workshop CORBA-HLA Architecture (sw view) Federate a Federate Code CORBA RTI Proxy Federate Ambassador CORBA RTI Ambassador RTI Executive Federate b Federate Code CORBA RTI Proxy Federate Ambassador CORBA RTI Ambassador CORBA RTI Server CORBA2Host Converter Local RTI Library RTI Ambassador CORBA RTI Server Host2CORBA Converter Local RTI Library RTI Ambassador (1) (2) (3) (4) (5) (6) (7) (8) (9) (11) (10) ORB IIOP IPC local calls
  22. 22. 2007 Euro Simulation Interoperability Workshop Example of use of CORBA-HLA (Running federates on a different HLA implementation ) RTI B Executive Federate 1 CORBA/HLA Client (Proxy) CORBA/HLA Server (RTI B) Federate 2 RTI B Local Library Site 1 Site 2 RTI A Executive CORBA/HLA Server (RTI A) RTI A Local Library IIOP IPC local calls
  23. 23. 2007 Euro Simulation Interoperability Workshop SimJ Objective: to improve reusability and adaptability
  24. 24. 2007 Euro Simulation Interoperability Workshop Improving reusability through … Bringing LP-level reusability. Simulation components (LP) can be reused across: • Several local environments • Local and distributed environment • Several distributed environments
  25. 25. 2007 Euro Simulation Interoperability Workshop Improving adaptability through … A uniform interface (of DES type) for both local and distributed execution That is: • Components are developed locally (as for any DES framework) • And then deployed either to local or distributed environments
  26. 26. 2007 Euro Simulation Interoperability Workshop SimJ • Provides a framework to develop local and distributed DES simulators • Supports the PI simulation paradigm • Is based on four layers • Defines service, data and factory interfaces
  27. 27. 2007 Euro Simulation Interoperability Workshop PI Paradigm E1 ev1 ev3 ev2 ev4 E2 E3 Key Entity Input Port Out Port Link/Event ev
  28. 28. 2007 Euro Simulation Interoperability Workshop SimJ Engines Current hierarchy (additions and restylings will not affect the other SimJ components) SimEngine ES_SimEngine AS_SimEngine PI_SimEngine PI_Local_SimEngine PI_HLA_SimEngine
  29. 29. 2007 Euro Simulation Interoperability Workshop Preliminary Experiments WAN GATech's LAN Lecce HLA over IIOP SimLab Executive HLA over IIOP US - Georgia Italy Server Local HLA over IIOP Federate Key pRTI 1516 CORBA + CORBA-HLA IIOP protocol Pitch protocol over TCP and UDP Georgia Tech CORBA-HLA Client Federation Manager TorVergata CORBA RTI Server Ascoli Camerino SimJ CORBA-HLA Client SimulatorSimJ CORBA-HLA Client Simulator SimJ CORBA-HLA Client Simulator SimJ CORBA-HLA Client Simulator SimJ CORBA-HLA Client Simulator SimJ CORBA-HLA Client Simulator
  30. 30. 2007 Euro Simulation Interoperability Workshop Conclusions • Distributed simulation software do not exploit advances of general-purpose distributed software • HLA, particularly, suffers from low levels of quality attributes (interoperability, reusability, adaptability) • We have introduced two technologies that improve such attributes: • CORBA-HLA improves interoperability and reusability • SimJ improves reusability and adaptability

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