Deep Space Network Emulation

1
Deep Space Network Emulation

• Shaun Endres and Behnam Malakooti
• Case Western Reserve University
• Department of Electrical Engineering and Computer
  Science
• Shaun.Endres, Behnam.Malakooti_at_case.edu
• Kul Bhasin and Allen Holtz
• NASA Glenn Research Center
• Space Communications
• Kul.B.Bhasin, Allen.P.Holtz_at_grc.nasa.gov

2
Introduction

• Presentation Outline
• Motivation
• Application
• Definition
• Overview
• Design
• Configuration
• Testing Results
• Conclusions

3
Motivation

• Network Analysis Motivation
• Performance assessment
• Risk assessment
• Deep Space Emulation Motivation
• No known tools for evaluating deep space networks
• Space Based Internet Emulator (University of
  Kansas)
• The Network Simulator (ns-2)
• Active Networking

4
Application

• Deep Space Network Nodes (Earth, Moon, Mars, and
  beyond)
• Ground stations
• Satellites
• Space shuttles
• Anything that the Satellite Tool Kit (STK) can
  handle
• Researchable Issues
• Protocols
• Routing algorithms
• Communication architectures

5
Network Emulation

• Definition
• Emulation refers to the ability to introduce a
  simulator into a live network.
• Comparison
• Simulation is _____ than emulation
• Less Expensive
• Faster (depending on the complexity)
• Less Accurate
• A real hardware test-bed is _____ than emulation
• Significantly more expensive
• More accurate
• Less controllable

6
Emulator Overview

• Emulator Features
• Completely in user space
• Any network, transport, or application layer
  protocol possible
• Strict cutoff between emulator and user
• Emulator Usage
• Emulator is transparent to the end user

7
Emulator Design (Control Emulation Network)

• Control Network
• Star Topology
• Sends Physical Information
• TCP/IP Used
• Link Always Available
• Error Free Link
• Emulation Network
• Fully Connected Network
• Sends Networking Information
• Researched Protocol Used
• Link Availability Based on
• Physical Information
• Error Prone Link

8
Emulator Design (Information Flow)

• Control Network
• Communicates with STK 7 to determine position
  and link information
• Updates all nodes link tables periodically
• Emulation Network
• Applies information contained in link tables to
  all out going packets
• Physical and Data Link Layers
• Modeled within the emulator code
• Network, Transport, and Application Layers
• Actual implementation (left up to the researcher
  to implement)

9
Emulator (Physical Setup)

• Hardware
• Cisco Catalyst 2900 series XL switch
• Intel Pentium III 600MHz processor computer with
  128MB of RAM
• Fast Ethernet
• Software
• STK 5.0.4
• Microsoft Windows XP Professional
• Microsoft Visual Studio .NET 2002
• Programming Language
• C

10
Results

• Delay Verification
• Delay Accuracy gets better as the delay increases
• With a 30s delay, there is about a 0.1 error
• Bit Error Rate Verification
• Bit error rate application has about a 0.25 error

11
Conclusions and Future Work

• Conclusions
• Deep Space Network Emulation is Possible Without
  Kernel Modifications
• Great Flexibility Can Be Given to the User
• OS Interrupt Timer Is Limiting Factor
• Future Work
• Multiple Nodes
• Bandwidth Restriction
• Deep Space Mission Scenario Analysis
• Protocol Testing for Deep Space Missions

12
Thank You

• Thank You for Your Time and Attention
• Any Questions?

13
Selected References

• 1 http//www.isi.edu/nsnam/ns/ns-emulation.html
• 2 Bateman, M., Allison, C., and Ruddle, A., A
  Scenario Driven Emulator for Wireless, Fixed and
  Ad Hoc Networks, 2003.
• 3 Zheng, P., and Ni, L. M., EMPOWER A Network
  Emulator for Wireline and Wireless Networks,
  IEEE INFOCOM, 2003.
• 4 Zheng, P., and Ni, L. M., EMPOWER A
  Scalable Framework for Network Emulation.
• 5 Zheng, P., and Ni, L. M., Experiences in
  Building a Scalable Distributed Network Emulation
  System.
• 6 Ingham, D. and Parrington, G., Delayline A
  Wide-Area Network Emulation Tool.
• 7 www.stk.com
• 8 Rallapalli, S., Emulation of a Space Based
  Internet Communication Link Design and
  Implementation, University of Kansas, 2000.
• 9 Baliga, S. R., Design of a Space Based
  Internet Emulation System, University of Kansas,
  2002.
• 10 Endres, S., Griffith, M., Malakooti, B.,
  Bhasin, K., and Holtz, A., Space Based Internet
  Network Emulation for Deep Space Mission
  Applications, AIAA ICSSC, May, 2004.
• 11 Sklar, B., Digital Communications
  Fundamentals and Applications, Prentice Hall,
  2001.
• 12 Herrscher, D., and Rothermel, K., A Dynamic
  Scenario Emulation Tool.
• 13 Carson, M., and Santay, D., NIST Net A
  Linux-based Network Emulation Tool.
• 14 Yeom, I., and Reddy, A. L., ENDE An
  End-to-end Network Delay Emulator.
• 15 Hu, Y., and Li, V. O. K., Satellite-Based
  Internet A Tutorial, IEEE Communications
  Magazine, 2001.

14
Additional Slides

• Additional Slides Begin Here

15
Improvements to Existing Tools

• Improvements to the Space Based Internet Emulator
• Any transport and network layer protocol
• No kernel modifications
• Deep space objects
• Header errors
• Improvements to The Network Simulator (ns-2)
• Deep space objects
• Highly dynamic link changes

16
Satellite Tool Kit (STK)

• Satellite Orbit Propagation
• Detailed satellite propagation
• Orbits around any planetary body
• Real time information
• STK/Connect can provide an application with real
  time information
• Link Budget Report
• STK/Communication can provide a detailed link
  budget report

17
Results (1 of 2)

• Worst Case Delay

Measured Target Difference Error
5.00675 4 1.00675 25.17
10.0135 8 2.0135 25.17
15.02025 12 3.02025 25.17
15.02025 16 0.97975 6.12
15.02025 20 4.97975 24.90
25.03375 24 1.03375 4.31
25.03375 28 2.96625 10.59
35.04725 32 3.04725 9.52
35.04725 36 0.95275 2.65
35.04725 40 4.95275 12.38
45.06075 44 1.06075 2.41
18
Results (2 of 2)

• Average Case Delay
• Bit Error Rate

Measured Target Difference Error
30030.49 30000 30.4865 0.10
30050.51 30000 50.5135 0.17
30035.49 30000 35.49325 0.12
30035.49 30000 35.49325 0.12
30020.47 30000 20.473 0.07
30040.5 30000 40.5 0.14
30020.47 30000 20.473 0.07
30015.47 30000 15.46625 0.05
30030.49 30000 30.4865 0.10
30035.49 30000 35.49325 0.12
Measured Target Difference Error
1 1 0 0.00
0.317118333 0.316228 0.000891 0.28
0.099778333 0.1 0.000222 0.22
0.03181 0.031623 0.000187 0.59
0.010053333 0.01 5.33E-05 0.53
0.003131667 0.003162 3.06E-05 0.97