1. A New Multipath Routing Protocol for Ad Hoc Wireless Networks
IEEE MAC
November 21, 2018
A New Multipath Routing Protocol for Ad Hoc Wireless Networks
Amit Gupta and Amit Vyas
November 21, 2018
Amit Vyas

2. Outline Motivation Intuition and Previous Work Problem Statement
Analysis
Simulations
Conclusion
EE384Y Project Presentation
June 5, 2002

3. Motivation Ad Hoc Wireless networks Very quickly deployable
Less costly than infrastructure networks
Applications
Internet connectivity in buildings
Connecting computers at a conference
Video-conferencing
Wireless sensor networks
Military communications and emergency services
EE384Y Project Presentation
June 5, 2002

4. Motivation
Interactive Applications place stringent demands on delay requirements (e.g. telnet or multimedia communication)
Lower delays might be more important than bandwidth used
Can we achieve lower delays by sending same packet over multiple paths ?
What is the trade-off between decrease in delays and increase in bandwidth ?
EE384Y Project Presentation
June 5, 2002

5. Outline Motivation Intuition and Previous Work Problem Statement
Analysis
Simulations
Conclusion
EE384Y Project Presentation
June 5, 2002

6. Intuition Send same packets along multiple paths
Lowers end-to-end probability of losses
In turn reduces expected number of retransmissions and number of timeouts
Hence decreases expected end-to-end delay
More relevant for wireless networks
They are more lossy than wired networks
But increases bandwidth requirements
Let us try to quantify this trade-off
EE384Y Project Presentation
June 5, 2002

7. Previous Work Old work More recently
Dispersity Routing – Maxemchuk (1975)
Efficient Dispersal of Information – Rabin (1989)
More recently
Apostolopoulos (2001)
Split a video into multiple streams and send different streams over different paths to achieve better quality
Liang, Steinbach, Girod (2001)
Real-time voice communication over the internet using packet path diversity.
Experimental setup in which they send packets over two paths using a relay server.
Also simulated two CBR voice streams via two paths using ns simulator
EE384Y Project Presentation
June 5, 2002

8. Outline Motivation Intuition and Previous Work Problem Statement
Analysis
Simulations
Conclusion
EE384Y Project Presentation
June 5, 2002

9. Problem Statement But no one has looked at
Impact of using extra paths on bandwidth
Trade-off between reduction in delay and extra bandwidth used
Optimal number of redundant paths
Depends on loss probability, time out values, number of hops
Application to routing protocols
EE384Y Project Presentation
June 5, 2002

10. Problem Statement Outline of Work Analysis of delay-bandwidth tradeoff
Study of loss models for wireless networks
Impact of various parameters on the optimum choice
Study of current Ad Hoc Wireless Routing Protocols
Design of a new protocol
Simulations using ns-2 network simulator
EE384Y Project Presentation
June 5, 2002

11. Outline Motivation Intuition and Previous Work Problem Statement
Analysis
Simulations
Conclusion
EE384Y Project Presentation
June 5, 2002

12. Analysis Loss model for wireless networks Nguyen et. al. (1996)
Trace-based approach for modeling wireless channel behavior
For AT&T WaveLAN, average packet error rate of 2-3 %
Improved two-state model (error, error-free)
Two & Three segment curves respectively for distribution
Konrad et. al (2001)
Markov based channel model
Algorithm to divide trace into stationary components
These models are very complicated and need very specific parameters
Simple probability model is good enough for our study
Burst losses and outages will only make our results better
EE384Y Project Presentation
June 5, 2002

13. Analysis Important parameters Metrics Loss probability over a link
Timeout for end-to-end retransmission
Number of hops
Number of paths
Additional delay of alternate path(s)
Metrics
Expected end-to-end delay
Expected bandwidth used
Delay-bandwidth product
EE384Y Project Presentation
June 5, 2002

14. Analysis Variation of number of paths EE384Y Project Presentation
June 5, 2002

15. Analysis Variation of number of paths EE384Y Project Presentation
June 5, 2002

16. Analysis Variation of number of hops EE384Y Project Presentation
June 5, 2002

17. Analysis Variation of number of hops EE384Y Project Presentation
June 5, 2002

18. Analysis Variation of additional delay of alternate paths
EE384Y Project Presentation
June 5, 2002

19. Outline Motivation Intuition and Previous Work Problem Statement
Analysis
Simulations
Conclusion
EE384Y Project Presentation
June 5, 2002

20. Current Ad Hoc Wireless Routing Protocols
Table-Driven Routing Protocols
Destination-Sequenced Distance Vector Routing (DSDV)
Clusterhead Gateway Switch Routing (CGSR)
The Wireless Routing Protocol (WRP)
Source-Initiated On-Demand
Ad Hoc On-Demand Distance Vector Routing (AODV)
Dynamic Source Routing (DSR)
Temporally Ordered Routing Algorithm (TORA)
Associativity-Based Routing
Signal Stability Routing
EE384Y Project Presentation
June 5, 2002

21. Simulations To validate the analysis results
Used the ns-2 simulator with wireless extensions
Modified DSR protocol to allow multiple paths – Dynamic Multipath Source Routing (DMSR)
Simulation Setup
Interested in study of delay-BW tradeoff for end-to-end error-recovery protocols (e.g. TCP)
Effect of number of hops and network load
Two scenarios – deterministic 16 nodes and uniform randomly distributed 30 nodes
EE384Y Project Presentation
June 5, 2002

22. Simulations Scenario of 16 nodes Relatively low network load
EE384Y Project Presentation
June 5, 2002

23. Outline Motivation Intuition and Previous Work Problem Statement
Analysis
Simulations
Conclusion
EE384Y Project Presentation
June 5, 2002

24. Conclusion Use of multiple paths for achieving lower expected delays
Studied effect of various parameters on the delay-bandwidth trade-off
Determined optimal number of redundant paths
Implemented scheme as DMSR Wireless Routing Protocol
Validated results using simulations
EE384Y Project Presentation
June 5, 2002

25. THE END
EE384Y Project Presentation
June 5, 2002