RTI Working Group Issues

1
RTI Working Group -- Issues
Object Models
HLA/RTI

• Endorsement of RPR FOM
• RDE Reference FOM
• Multiple Inheritance Impacts in FOMs
• Non-object Model Federation Data for
  Interoperability
• Requestable Objects

• HLA Use Cases for RDE
• RDE Lessons-learned With HLA
• RTI Goals (Timing, BW)
• RTI Integration Tools
• Interoperability Between RTIs
• Multiple routing of attributes

Other
Fidelity

• SISO-sponsored Fidelity Group
• Fidelity Glossary
• Fidelity Characterization in SOMs
• Fidelity in OM Tools

• SIW Paper Review Requirements

2
RDE Lessons-learned With HLA

• Abstract The potential RDE uses of HLA need to
  be sufficiently well characterized to ascertain
  the functional or performance needs on the RTI or
  middleware products.
• Narrative The RDE will develop, disseminate,
  collect and publish summary application profiles
  for active/planned HLA experiments within the
  RDE community. The RDE will encourage the
  preparation of DMSO-standard Federation Execution
  Planning Workbook Templates for experiments in
  which it is possible to do so. The RDE will
  encourage preparation and presentation of
  lessons-learned from such experiments. The RDE
  endeavor to extract significant conclusions and
  trends from the assembled reports, and
  proactively communicate them to appropriate SISO,
  DMSO and user organizations.

3
HLA Experiments Being Monitored by RDE User Forum
4
Summary Experiment Description
5
HLA Use Case Definition for RDE

• Abstract The pacing or key future RDE
  applications of HLA must be sufficiently well
  characterized to ensure that the RTI and related
  HLA services are responsive to the emerging
  needs.
• Narrative The RDE User Forum will review the
  planned 1997/98 community experiments to assess
  the degree to which they span the realm of core
  simulation community applications in the
  1998-2003 timeframe.
• To the extent that key application areas are not
  represented, the RDE will investigate the
  potential for defining Use Cases appropriate for
  capability planning and future testing.

6
RDE Use Case -- RDE-RT-1High dynamic, real-time
user

• X vs. X Fighter Aircraft Federation based on
  SIW-98S-042 and associated Federation Execution
  Notebook
• Two example scenarios
• Synchronous platform pos-vel state data, with
  infrequent full MilitaryPlatformEntities updates.
  Best effort receive order. Reliable transport of
  infrequent events. Scale from 1 Vs. 1 to M vs. M.
  Peak latency is key performance metric (1/60 Hz).
• Synchronous platform pos-vel state data, with
  infrequent full MilitaryPlatformEntities updates
  1 vs. M scenario. Bursty transmission of
  asynchronous event sequences (0-100/sec). Best
  effort or reliable receive order. Peak latency
  is key performance metric (100 msec).

7
Tentative RDE Use Case Class Descriptions

• Real-time (RT) - Emphasis is on real-time or
  pseudo-real-time execution. Data latency is
  generally a core concern. Most current DIS
  applications fall in this category. Best effort
  often suffices.
• Complex Models (CM) - Characterized by
  engineering federations with complex (deep) model
  hierarchies, attribute sets and subscribe/reflect
  mappings.
• Proliferated Objects (PO) - Federations with
  large numbers of atomic entities (tanks, mines,
  ).
• Hardware-in-the-loop (HW) - Require interface
  with (servicing of) real military hardware
  devices, from entity to component level.
  Generally requires time synchronization to
  external standard and reliable transport.

8
Use Case Documentation Needs
Scenario Descriptions
Fed Ex Notebooks
Task Flow Descriptions
9
Use Case Implementation PlanMerge Object
Management and RTI WG Perspectives
Jan.
Mar.
Jun.
Sept.
I/ITSEC Dec. 1998
Interim
SISO
Interim
SISO

• Jan Developed Initial Concept
• Mar Brief and Obtain General Concensus
• Jun Focused Planning (Participant Federates)Use
  Case Development
• Sept Review Final PlansComplete Experiments
• Dec Present Findings at I/ITSEC

10
RTI Attribute Reflect Servicing Performance

• Abstract Timed tests at AFRL with RTI 1.0.2
  suggest that RTI Ambassador servicing of the tick
  function may consume as much as 80 of a users
  total reflect attribute cycle time. Request that
  DMSO ensure that the RTI service for releases
  1.3 substantially improve responsiveness. For
  Use Case RDE-RT-1A, a 10-fold improvement to only
  25-30 of total event processing time is
  reasonable goal. Failure to reduce the overhead
  will severely impact some planned federations.

• Narrative AFRL executed an X vs. X aerial
  engagement federation with simple
  MilitaryPlatformEntities, receive-order event
  processing, not time regulated. On average, 80
  of the apps time for processing attribute
  updates is consumed in RTI Ambassador processing.

11
RTI Integration Tools

• Abstract The HLA applications community needs
  tools or protocols which permit users to
  characterize the status/impact of RTI loading,
  data handling and message traffic on the
  execution of their federations.
• Narrative Typical RDE users are constructing
  HLA-based exercises to meet specific objectives,
  subject to various resource (CPU, bandidth)
  constraints and performance goals (timing). The
  inability to read (or tag) RTI messages on the
  wire seriously hampers users in their attempts
  to characterize execution of their federation and
  intelligently implement strategies for optimizing
  performance to meet their objectives. Execution
  monitoring tools for RTI performance are
  essential performance prediction tools are
  desirable.

12
RTI Bandwidth

• Abstract Future RTI releases need to improve the
  packaging efficiency of packets to avoid
  penalizing current DIS users.
• Narrative In a real-time application focused on
  exchange of platform entity state information
  (RDE Use Case RDE-RT-1), packet efficiency with
  RTI 1.0.2 was substantially lower than a
  comparable DIS protocol implementation, requiring
  92 bytes of RTI overhead to transport 60 bytes of
  information. If not addressed future RTI
  releases, this inefficiency will prevent current
  DIS users from realizing the bandwidth savings
  potential of HLA.

13
Interoperability between dissimilar RTIs

• Abstract The RDE forum is concerned about
  potential interoperability barriers introduced by
  the anticipated proliferation of RTI
  implementations. The RDE forum encourages the
  discussion of architectural approaches that may
  be utilized to further promote interoperability
  amongst extended federates.