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1 12/4/2003 1 Authors : Vincent D. Parka ,M. Scott Corson University of Maryland, USA

A Highly Adaptive Distributed Routing Algorithm for Mobile Wireless Networks Temporally-Ordered Routing Algorithm (TORA) IEEE INFOCOM. 1 12/4/2003 1 Authors : Vincent D. Parka ,M. Scott Corson University of Maryland, USA Speaker: Chang Pei-Chen Wireless & Mobile Network Lab

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1 12/4/2003 1 Authors : Vincent D. Parka ,M. Scott Corson University of Maryland, USA

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  1. A Highly Adaptive Distributed Routing Algorithm for Mobile Wireless Networks Temporally-Ordered Routing Algorithm (TORA) IEEE INFOCOM 112/4/20031Authors :Vincent D. Parka ,M. Scott Corson University of Maryland, USA Speaker: Chang Pei-Chen Wireless & Mobile Network Lab TamKang University

  2. Overview • Introduction • Temporally-Ordered Routing Algorithm • Conclusion

  3. B C A D G F E TORA - Overview • Each destination,TORA maintains a DAG A C B C DEST D A D G G F E E F C Increase the height B A D G E F

  4. Introduction - Network Considerations • A Collection of Mobile Wireless Routers • Connection status dependent on: • Node position • Transmission power • Antenna patterns • Interference levels • Result in an Unpredictable, Dynamic network • Link Congestion

  5. Introduction - Desirable Attributes of a Routing Algorithm • Executes Distributed • Provides loop-free routes • Provides multiple routes (to alleviate congestion) • Establishes routes quickly (so they may be used before the topology changes) • Minimizes communication overhead by localizing algorithmic reaction to topological • Changes when possible (to conserve available bandwidth and increase scalability)

  6. Introduction - TORA Attributes • On demand, Source initiated routing • Distributed in that nodes only maintain one hop knowledge • Provides multiple routes to alleviate congestion • Creates loop free routes • Handles partitions by erasing invalid routes

  7. Route Creation Node C requires a route to Node F (-,-,-,-,B) (-,-,-,-,A) A B (-,-,-,-,E) C (-,-,-,-,C) E D (-,-,-,-,D) (-,-,-,-,F) F G (-,-,-,-,G) H (-,-,-,-,H)

  8. Route Creation It broadcasts a QRY packet. Circle around indicates RRi is Ture (-,-,-,-,B) (-,-,-,-,A) A B (-,-,-,-,E) C QTY (-,-,-,-,C) E QTY D (-,-,-,-,D) (0,0,0,0,F) DEST F G (-,-,-,-,G) H (-,-,-,-,H)

  9. Route Creation Sets RRi Flag Rebroadcasts the QRY Packet. (-,-,-,-,B) (-,-,-,-,A) A B QTY (-,-,-,-,E) C (-,-,-,-,C) QTY E D (-,-,-,-,D) (0,0,0,0,F) DEST QTY F G (-,-,-,-,G) H (-,-,-,-,H)

  10. Route Creation Node B , D , H propagate the QRY Packet (-,-,-,-,B) (-,-,-,-,A) A B QTY (-,-,-,-,E) C (-,-,-,-,C) QTY E D (-,-,-,-,D) (0,0,0,0,F) DEST QTY F G (-,-,-,-,G) H (-,-,-,-,H)

  11. Route Creation Node B , D , Sets RRi Flag and Rebroadcast the QRY Packet (-,-,-,-,B) (-,-,-,-,A) A B (-,-,-,-,E) QTY C (-,-,-,-,C) QTY E D (-,-,-,-,D) QTY (0,0,0,0,F) DEST F G (-,-,-,-,G) H (-,-,-,-,H)

  12. Route Creation At the Same Time Node D propagate the QTY Packet and Follow the Rule 3 (-,-,-,-,B) Node D sets it height to Hi=(0,0,0,1,H) and broadcasts the UPD Packet (-,-,-,-,A) A B (-,-,-,-,E) C (-,-,-,-,C) E D (-,-,-,-,D) (0,0,0,0,F) DEST UPD F QTY G (-,-,-,-,G) H (-,-,-,-,H) (0,0,0,1,H) UPD

  13. Route Creation Node D follow the QTY Rule 2 Node E follow the QTY Rule 3 (-,-,-,-,B) (-,-,-,-,A) Node H follow the QTY Rule 4 A B UPD (-,-,-,-,E) QTY (0,0,0,1,E) C (-,-,-,-,C) QTY E D (-,-,-,-,D) QTY (0,0,0,0,F) DEST UPD F G (-,-,-,-,G) H (0,0,0,1,H) UPD

  14. Route Creation Node D and G follow the UPD Rule 1 (-,-,-,-,B) (-,-,-,-,A) A B UPD C UPD (0,0,0,1,E) (-,-,-,-,C) E D (-,-,-,-,D) (0,0,0,2,D) UPD (0,0,0,0,F) DEST UPD F G (-,-,-,-,G) (0,0,0,2,G) H (0,0,0,1,H) UPD

  15. Route Creation Node G , B and A follow the UPD Rule ,1 (-,-,-,-,B) (0,0,0,2,B) (-,-,-,-,A) (0,0,0,3,A) A B C UPD (0,0,0,1,E) (-,-,-,-,C) (0,0,0,3,C) E D (0,0,0,2,D) UPD (0,0,0,0,F) DEST F G (0,0,0,2,G) H (0,0,0,1,H)

  16. Route Creation Node A follow the UPD Rule ,1 UPD (0,0,0,3,A) (0,0,0,2,B) UPD A B (0,0,0,3,C) C (0,0,0,1,E) E D (0,0,0,2,D) (0,0,0,0,F) DEST F G (0,0,0,2,G) H (0,0,0,1,H)

  17. Route Creation (0,0,0,2,B) UPD A B (0,0,0,3,C) C (0,0,0,1,E) E D (0,0,0,2,D) (0,0,0,0,F) DEST F G (0,0,0,2,G) H (0,0,0,1,H)

  18. Erasing Routing • Erasing Routing is performed when network partition is detected • When network partition is detected,” Clear packet ” (CLR) is flooding throughout the network to erase invalid routes.

  19. Summary • (TORA algorithm )Link reversal mechanism • Advantage • Loop-Free Multipath routing protocol • Minimizes communication overhead • Rapidly adapts to topological changes • Detects network partitions and erase all invalid routes within a finite time • Localize its reaction to topological changes • Drawback: • It does not select optimal path • Limited primarily by storage complexity, which only grows linearly with the number of nodes in the network

  20. Conclusions • Proposed a highly adaptive distributed routing algorithm that well-suited in mobile wireless networks • Decouple the generation of far-reaching control message propagation from the dynamics of the network topology • Possible enhancement would be to periodically propagate refresh packets outwards from the dest. • The refresh process permits intro of far-reaching control message propagation into the protocol independent of the network topology

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