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

18
Results (2 of 2)

• Average Case Delay
• Bit Error Rate