1. Load Balancing of Multipath Source Routing in Ad Hoc Networks Lianfang Zhang, Zenghua Zhao, Yantai Shu, and Lei Wang Department of Computer Science Tianjin University, Tianjin 300072, China

2. Outline I. Introduction II. An Overview To MSR III. Model Based Analysis IV. Simulation Result V. Conclusion

3. I.Introduction(1/2) Mobile ad hoc networks are characterized by multi-hop wireless links, the absence of any cellular infrastructure, and frequent host mobility Manage frequent topology changes and need to be bandwidth- and power-efficient

4. I.Introduction(2/2) DSR Single path routing under-utilize resources and can not cope with congestion and link breakage MSR Probing mechanism Refresh the information in cache, to delete stale path and to fined new one in time

5. II.An Overview to MSR Maintaining alternative paths requires more routing table space and computational overhead Source routing is flexible The on-demand nature of DSR can reduce greatly the routing storage and routing computation

6. II.A. Path Finding Path information →Route cache To achieve high path independence, disjoint paths are preferred in MSR. No looping problem

7. II.B. Probing and Load Balancing Use probing as a feed back control mechanism Send probing packets periodically to each path and measure their round-trip time Estimate path delay Distribute traffic over different paths in order to achieve a minimum mean delay for the whole network

8. III. Model Based Analysis Intermediate nodes would do nothing except to forward the packet Adding no more processing complexity than DSR All path calculation is done in the source hosts and optimal routing is intimately related to load balancing

9. III.A. General Analysis on Load Balancing(1/3) N parallel M/M/1 queues

10. III.A. General Analysis on Load Balancing(2/3) Objective Subject to

11. III.A. General Analysis on Load Balancing(3/3) (1) (2) (3)

12. III.B. Delay Performance Evaluation in Two-path Case(1/4)

13. III.B. Delay Performance Evaluation in Two-path Case(2/4) Assuming and

14. III.B. Delay Performance Evaluation in Two-path Case(3/4)

15. III.B. Delay Performance Evaluation in Two-path Case(4/4) Since, after substituting

16. III.B. Delay Performance Evaluation in Two-path Case

17. III.C. Discussion on the Heuristic Equation(1/3) Eqn. (6) shows that the difference between the traffic distributed on any two paths must be proportional to the difference of the paths’ average packet. (6)

18. III.C. Discussion on the Heuristic Equation (2/3) refers to the weight of path measured in number of packets to be sent consecutively on the same path every time

19. III.C. Discussion on the Heuristic Equation (3/3) If we distribute traffic according to the weights, we may achieve near-optimal routing is a factor to control the frequency of switching between routes is a bound to insure that should not to be too large

20. IV. Simulation Result(1/3) CBR UDP FTP TCP

21. IV.B. Simulation Result (2/3)

22. IV.B. Simulation Result (3/3)

23. V. Conclusion End-to-end delay Network resource

24. Future Work Study of optimal load balancing scheme QoS support in MSR