1. SHORT: Self-Healing and Optimizing Routing Techniques for Mobile Ad Hoc Networks Presenter: Sheng-Shih Wang October 30, 2003 Chao Gui and Prasant Mohapatra Computer Science Department, University of California Davis ACM MobiHoc, vol. 2, 2003, pp. 279-290

2. October 30, 2003 Sheng-Shih Wang Outline  Introduction  Path Aware (PA)-SHORT  Energy Aware (EA)-SHORT  Simulation  Conclusion

3. October 30, 2003 Sheng-Shih Wang Introduction  Routing Protocol Categories Table-driven vs. on-demand  Proposed Routing Protocol Self-Healing and Optimizing Routing Technique (SHORT) Self-Healing and Optimizing Routing Technique (SHORT) Reduce energy consumption Less overhead Path Aware (PA)-SHORT Reduce the number of hops Energy Aware (EA)-SHORT Conserve power

4. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Problem Description A B C D E F G H I Initial path (after route discovery process) --- 8 hops Initial path (after route discovery process) --- 8 hops A B C D E F G H I J J, E, and H is in the transmission ranges of A, J, and F, respectively Mobility (but retain connectivity) Mobility (but retain connectivity) Desired path (after mobility) --- 5 hops Desired path (after mobility) --- 5 hops A E F H I J

5. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Basic Short-Cut Path Formations  ( n, k )  n routing hops can be reduced to k hops Hop (2,1) short-cut Hop (3,2) short-cut

6. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Short-cut Occurrence Analysis Experimental model (proportion of packets encountering short-cuts) Experimental model (proportion of packets encountering short-cuts) (n,2) short-cut is much more frequent than (n,1) short-cut (n,2) short-cut is much more frequent than (n,1) short-cut

7. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Properties  Work with any underlying routing protocol  Shorten the route according to the up-to-date topology  Different routing protocol uses different SHORT  Hop comparison array In packet header SA  Source Address DA  Destination Address HC  Hop-Count NA  Neighbor’s (Sender) Address (current HC – stored HC) > 2  a short-cut path exists

8. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Example A B C D E F G H I J

9. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Example (cont.) A B C D E F G H I J 0 0

10. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Example (cont.) A B C D E F G H I J current HC(1) – stored HC(0) = 1  nothing is updated 1 1

11. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Example (cont.) A B C D E F G H I J 2 2

12. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Example (cont.) A B C D E F G H I J 3 3

13. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Example (cont.) UPDATE !!! current HC(4) – stored HC(0) = 4  UPDATE !!! node J sends message to A to update its routing table node J modifies its own routing table A B C D E F G H I J 4 4 4

14. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Example (cont.) A B C D E F G H I J 5 5 5

15. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Example (cont.) A B C D E F G H I J 6 6

16. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Example (cont.) A B C D E F G H I J 7 7 7 UPDATE !!! current HC(7) – stored HC(4) = 3  UPDATE !!! node F sends message to E to update its routing table

17. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Example (cont.) A B C D E F G H I J Before Self-Healing Before Self-Healing After Self-Healing After Self-Healing A E F H I J

18. October 30, 2003 Sheng-Shih Wang Energy Aware (EA)-SHORT --- Concept  Goal Balance the energy consumption at all nodes  Idea Divert the traffic to other nodes

19. October 30, 2003 Sheng-Shih Wang Energy Aware (EA)-SHORT --- Basic Cases 1 SACD B P Data packets are successively forwarded by A, B, and C, node P can overhear the same packet three times (from A, B, and C) If node P sees the current energy level of node B, and find out that the difference of energy level as node B and itself is significant enough Node P will do the redirection

20. October 30, 2003 Sheng-Shih Wang Energy Aware (EA)-SHORT --- Example 1 AC B P 232 4 Overhear table kept in each node has 3 fields: source-destination pair sequence number overhear list:

21. October 30, 2003 Sheng-Shih Wang Energy Aware (EA)-SHORT --- Example 1 (cont.) AC B P 232 4 [S-D, 1, ]

22. October 30, 2003 Sheng-Shih Wang Energy Aware (EA)-SHORT --- Example 1 (cont.) AC B P 232 4 [S-D, 1, ]

23. October 30, 2003 Sheng-Shih Wang Energy Aware (EA)-SHORT --- Example 1 (cont.) AC B P 232 4 [S-D, 1, ] (HC(B) == HC(A) + 1) AND (lvl(P)  MAX(lvl(A), lvl(B) + 2)  candidate B

24. October 30, 2003 Sheng-Shih Wang Energy Aware (EA)-SHORT --- Example 1 (cont.) AC B P 232 4 [S-D, 1, ]

25. October 30, 2003 Sheng-Shih Wang Energy Aware (EA)-SHORT --- Example 1 (cont.) AC B P 232 4 [S-D, 1, ] HC(C) == HC(B) + 1 == HC(A) + 2 lvl(P)  MAX(lvl(A), lvl(C) lvl(P)  MAX(lvl(B)) + 2 activate this new subpath

26. October 30, 2003 Sheng-Shih Wang Energy Aware (EA)-SHORT --- Example 1 (cont.) AC B P 232 4

27. October 30, 2003 Sheng-Shih Wang Energy Aware (EA)-SHORT --- Basic Cases 2 Data packet travels along node A, B, and C, node P knows that it is a neighbor of both node B and its up-stream on-route neighbor (i.e., node A) Node Q finds that node B needs to be circumvented and Q is adjacent with the down-stream on-route neighbor of node B (i.e., node C) Node Q broadcasts a message to find the up-stream of node B Node P gets the message, and replies with an acknowledgement SACDB P Q

28. October 30, 2003 Sheng-Shih Wang Energy Aware (EA)-SHORT --- Example SBA C D T E 22 444 SBA C D T E 22 444 Case 2 SBA C D T E 22 444 Case 1

29. October 30, 2003 Sheng-Shih Wang Simulation Environment  ns-2 simulator Radio model is based on Lucent Technologies WaveLAN product Transmission rate: 2 Mbps Transmission range: 250 m MAC layer with DCF

30. October 30, 2003 Sheng-Shih Wang PA-SHORT Simulation --- Simulation Setup  Mobility model 100 mobile nodes Transmission range: 2000m  6000m Pause time (mobility rate): 45, 90, 180, 270, 540 and 720 simulation seconds  Traffic model 16 simultaneous flows with source-destination pairs spreading randomly Packet size: 256 bytes

31. October 30, 2003 Sheng-Shih Wang PA-SHORT Simulation --- Path Optimality path optimality  the ratio of the number of hops a packet took to reach its destination over the shortest hop distance between the source-destination pair at the time the packet is sent AODV does not guarantee shortest path DSR is better than AODV because it enjoys (n,1) short-cut

32. October 30, 2003 Sheng-Shih Wang PA-SHORT Simulation --- Delivery Rate The loss rate is proportional to the route length

33. October 30, 2003 Sheng-Shih Wang PA-SHORT Simulation --- Routing Overhead routing overhead  the total number of routing packets (short-cut information messages are included) divided by the total number of delivered packets

34. October 30, 2003 Sheng-Shih Wang PA-SHORT Simulation --- Number of Route Requests number of route requests  re-broadcasts packets are not counted

35. October 30, 2003 Sheng-Shih Wang EA-SHORT Simulation --- Simulation Environment 5 src nodes 5 dest nodes 5 src nodes 5 dest nodes

36. October 30, 2003 Sheng-Shih Wang EA-SHORT Simulation --- Simulation Setup Non-uniform traffic 120 nodes 100 nodes are forwarding nodes 20 nodes are traffic nodes 10 nodes are traffic source nodes 10 nodes are sink nodes Transmission range: 1200m  1200m Maximum moving speed: 1, 10, and 20 m/s Pause time: 0, 200, and infinite seconds Packet size: 256 bytes

37. October 30, 2003 Sheng-Shih Wang EA-SHORT Simulation --- Network Capacity Time- Line pause time  200 secs moving speed  10 m/s 6 packets per second per flow

38. October 30, 2003 Sheng-Shih Wang Conclusion  SHORT Improve routing optimality dynamically Redirect the path to the current more optimal one Higher delivery rate Longer network lifetime  Future work QoS requirement Multicast tree/mesh constructions

39. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Special Case 1 A B C Q D source

40. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Special Case 1 A B C Q D NO UPDATE !!! Source node receives the packet with HC  2 sent from its neighbor  UPDATE !!!

41. October 30, 2003 Sheng-Shih Wang Path Aware (PA)-SHORT --- Special Case 2 A B C D E F A B C D E G F destination Destinations do an additional broadcast