Federated Simulations Development Kit FDK

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Federated Simulations Development Kit(FDK)
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Outline

• FDK Overview
• RTI-Kit Software
• BRTI and DRTI
• Group Communication MCAST
• Time Management TM-Kit

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Federated Simulations Development Kit (FDK)
Jane GUI
Remote User
Compute Server

• RTI-Kit software for experimental research in
  RTIs
• Jane interactive simulation monitoring and
  control

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RTI-Kit

• Libraries implementinh RTI services
• MCAST group communication software
• distributed group management, name server
  functions
• current implementation built over unicast
• application-defined buffer allocation to minimize
  data copying
• TM-Kit algorithms for implementing time
  management
• fast distributed snapshot algorithm
• scalable (O(log N) time for global reduction
  operations
• buffer management, priority queues, random number
  libraries
• RTIs using RTI-Kit
• B-RTI (Basic RTI) HLA-like API (simplified)
• D-RTI (Detailed RTI) Subset of HLA services
• Platforms
• Platforms PC (Linux), SGI (Irix), Sun
• Networks Myrinet, shared memory, IP networks

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RTI-Kit Software
federates
RTI Interface (use one)
B-RTI Simple interface
D-RTI HLA interface
MCAST (group communication)
TM-Kit (time management algorithms)
DDM-Kit (data distribution software)
RTI-Kit libraries
other libraries buffer management priority
queues, etc.
FM-Lib Comm Libraries (use one)
Shared memory
IP protocols
Myrinet
Physical network
not included in current release
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RTIs

• BRTI
• Simple example RTI
• Does not attempt to conform to HLA IF/Spec
• DRTI
• Similar functionality to BRTI, services conform
  to v. 1.3 HLA IF/Spec
• Limit set of services (federation management,
  declaration management, object management, time
  management)

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MCAST

• MCAST group communication software
• distributed group management, name server
  functions
• current implementation built over unicast
• cache group membership information
• application-defined buffer allocation eliminates
  data copying within MCAST

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MCAST API

• Group Management
• MCAST_Create create group
• MCAST_GetHandle obtain handle for group from
  name server
• MCAST_Subscribe join group
• MCAST_Unsubscribe leave group
• Sending / Receiving Messages
• MCAST_Send send message
• WhereProc callback invoked for each incoming
  message (typically to allocate memory for
  incoming message)
• MessageHandler callback invoked for each
  subscriber for each incoming message
• EndProc optional callback invoked after all
  message handlers have been called

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TM-Kit

• Compute each processors Lower Bound on Time
  Stamp (LBTS) of future messages that could later
  arrive
• LBTS computation
• Based on distributed snapshot algorithm
• Similar to Matterns GVT algorithm
• Butterfly network for reduction computation and
  distribution of results
• Wait until all transient messages received before
  reporting final LBTS value

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HLA Time Management

• deliver messages to federate in time stamp order
• ensure federate does not receive an event in its
  past

• LBTSi lower bound on time stamp of messages
  that could later arrive for federate i
• TSO messages w/ TS LBTSi eligible for delivery
• RTI ensures logical time of federate i never
  exceeds LBTSi

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TM-Kit Implementation

• any processor can start an LBTS computation at
  any time
• callbacks to RTI software used to
• Indicate another processor has started an LBTS
  computation
• LBTS computation has completed
• simultaneous initiations by more than one
  processor automatically combined
• multiple pending LBTS computations allowed a
  processor can initiate a new computation even if
  previously initiated one(s) pending
• allows variety of methods to initiate LBTS
  computations
• each processor starts a new computation as
  needed (done here)
• central controller can responsible for starting
  LBTS computations

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TM-Kit API

• TM_StartLBTS initiate an LBTS computation
• StartHandler callback invoked when LBTS
  computation initated by another processor is
  detected
• DoneHandler callback invoked when LBTS
  computation completed
• Transient Messages
• TM_PutTag called prior to sending message to
  write tag (color) into message
• TM_Out called after message (event) is sent
• TM_In called when message (event) is received

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Summary

• FDK Software provides
• Libraries implementing primitives for realizing
  RTIs
• Sample RTIs (BRTI, DRTI)
• Jane GUI/Remote execution
• MCAST Library
• Pub/Sub communication primitives
• TM-Kit Library
• LBTS Computations for time management