Real Time Evaluation of RTI Version 1'3

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Real-Time Performance of RTI Version 1.3
ROGER D. WUERFEL HALIFAX CORPORATION
WRIGHT-PATTERSON AFB, OH
CAPT. RONNY JOHNSTON AFRL/VACD WRIGHT-PATTERSON
AFB, OH
presented by ERNEST F. PAYNE HALIFAX CORPORATION
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Overview

• Facility
• Objectives
• Approach
• Results
• Lessons Learned
• Summary

HALIFAX CORPORATION
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AFRL/VACD Simulator Networking Interests

• High fidelity simulations of dynamic air vehicles
  on a network
• What does the pilot perceive across networks?
• end-to-end delays and latency
• spatial accuracy
• bandwidth
• Measurement of network performance
• understand where improvements are needed
• Improvements to efficiency of protocols
  architectures
• What are the best network architectures?

HALIFAX CORPORATION
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SNAP Pinpointed these Problems

• Simulator networks often do not meet performance
  requirements for highly dynamic air vehicles
• Identified NIU as a large contributor to latency
• Protocol inefficiencies
• Network architectures may not be optimized for
  real-time simulation.

HALIFAX CORPORATION
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NETS/HLA Evaluation
NETWORKING ARCHITECTURES AND PROTOCOL
EVALUATIONS FOR THE TRAINING SYSTEMS PRODUCT
GROUP (TSPG)

• HLA Evaluation
• Study to understand HLAs impact on real-time
  networking performance

• NETS Architecture Study
• Study of DIS networking architectures for small
  numbers of Unit Training Devices (UTD)

HALIFAX CORPORATION
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NETS - SCRAMNet Architecture
HALIFAX CORPORATION
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Objective of HLA Evaluation
The purpose of the High Level Architecture (HLA)
Evaluation is to compare its performance in
flight simulator systems to the performance of
the previous technologywhich at the time was the
Distributed Interactive Simulation (DIS)
protocol
HALIFAX CORPORATION
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Approach

• Integrate RTI 1.3v2 for Silicon Graphics into the
  Network Evaluation for Training Systems (NETS)
  testing setup
• Evaluate HLA performance as a function of network
  loading
• local area and wide area end-to-end latency
• bandwidth
• accuracy

HALIFAX CORPORATION
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HLA Architecture
HALIFAX CORPORATION
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Hardware

• 2 Encore RSX machines
• 1 for each manned player
• SG Challenge machine
• 8 200 MHz R4400 processors
• E-Plex board for Ethernet connections
• IRIX 6.2
• Synchronized through external interrupts or
  shared memory flags

HALIFAX CORPORATION
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HLA Evaluation Software

• HLA Evaluation used RTI 1.3v2
• Each HLA NIU was isolated to its own CPU using
  REACT 3.0
• RPR-FOM 0.1.5
• Only data for MilitaryPlatformEntity sent
• GPS time used for dead reckoning
• Receive-order event processing
• No time regulation
• Best Effort

HALIFAX CORPORATION
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Testing Loads

• Loading was increased by increasing the number of
  digital entities and their performance
  characteristics
• 8 Trim had 4 entities on each LAN flying at trim
  condition
• Next had 1 entity on each LAN performing high-G
  maneuver
• Rest increased by 1 per side the number of
  entities performing high-G maneuver

HALIFAX CORPORATION
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Test Matrix
Test
Thresholds Run Load Entities (deg,m,sec) Pro
tocol 1 8 trim 8
3,1,5 RTI 1.3 2 1v1 8
3,1,5 RTI 1.3 3 2v2 8
3,1,5 RTI 1.3 4 3v3 8 3,1,5 RTI
1.3 5 4v4 10 3,1,5 RTI
1.3 6 5v5 12 3,1,5 RTI
1.3 7 6v6 14 3,1,5 RTI
1.3 8 7v7 16 3,1,5 RTI
1.3 9 8v8 18 3,1,5 RTI
1.3 10 9v9 20 3,1,5 RTI
1.3
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Network Delay Measurements
SCRAMNet to Ethernet
Ethernet to SCRAMNet
Encore to SCRAMNet
SCRAMNet to Encore
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Latency MeasurementsHLA vs. DIS vs. DIS-Lite
Memory to Ethernet (send)
Time (ms)
Loading
HALIFAX CORPORATION
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Percent of Send Time for updateAttributeValues
Time (ms)
Loading
HALIFAX CORPORATION
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Latency MeasurementsHLA vs. DIS vs. DIS-Lite
Ethernet to Memory (receive)
Time (ms)
Loading
HALIFAX CORPORATION
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Percent of Receive Time to Process Message
Percent
Loading
HALIFAX CORPORATION
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Latency MeasurementsHLA vs. DIS vs. DIS-Lite
Protocol Processing Time
16.67
Time (ms)
Loading
HALIFAX CORPORATION
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Bandwidth MeasurementsHLA vs. DIS vs. DIS-Lite
Bandwidth
Kbps
Loading
HALIFAX CORPORATION
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Packet MeasurementsHLA vs. DIS vs. DIS-Lite
Number of Packets
Packets
Loading
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Packet Efficiency
Bytes
Protocol
HALIFAX CORPORATION
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HLA Evaluation Results Summary

• With Respect to NETS.
• Ethernet packet inefficiencies
• Higher bandwidth consumption for equivalent
  simulations
• Higher Processing Overhead
• Increases NIU latency
• May limit number of highly-dynamic entities in a
  real-time simulation

HALIFAX CORPORATION
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HLA Lessons Learned

• Ethernet ports for data traffic can be specified
  now in 1.3v2.
• Recompilation went very smooth.
• Version Transition was easy.
• No data format of Ethernet packets on wire
  available
• SNAP would have to be intrusive to the federation
  to capture attributes from Ethernet packets
• It is desirable to have decoding functions

HALIFAX CORPORATION
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HLA Evaluation Summary

• Learned how HLA impacts network simulations
• Baselined performance of RTI 1.3v2
• Identified areas which need improvement
• Understand problems early so that research can
  have positive impact on the development of HLA
  for real time simulator applications

HALIFAX CORPORATION
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HLA Future

• We would like to repeat our experiment with the
  newer versions of HLA.
• We would like to measure under realistic
  simulations conditions.

HALIFAX CORPORATION
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Real-Time Performance of RTI Version 1.3
ROGER D. WUERFEL HALIFAX CORPORATION
WRIGHT-PATTERSON AFB, OH
CAPT. RONNY JOHNSTON AFRL/VACD WRIGHT-PATTERSON
AFB, OH
presented by ERNEST F. PAYNE HALIFAX CORPORATION