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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. Outline. Introduction An Overview To MSR Model Based Analysis Simulation Result Conclusion.
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Load Balancing of Multipath Source Routing in Ad Hoc Networks Lianfang Zhang, Zenghua Zhao, Yantai Shu, and Lei WangDepartment of Computer ScienceTianjin University, Tianjin 300072, China
Outline • Introduction • An Overview To MSR • Model Based Analysis • Simulation Result • Conclusion
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
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
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
II.A. Path Finding • Path information →Route cache • To achieve high path independence, disjoint paths are preferred in MSR. • No looping problem
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
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
III.A. General Analysis on Load Balancing(1/3) N parallel M/M/1 queues
III.A. General Analysis on Load Balancing(2/3) Objective Subject to
III.A. General Analysis on Load Balancing(3/3) (1) (2) (3)
III.B. Delay Performance Evaluation in Two-path Case(2/4) • Assuming and
III.B. Delay Performance Evaluation in Two-path Case(4/4) Since , after substituting
III.C. Discussion on the Heuristic Equation(1/3) (6) 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.
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
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 bound to insure that should not to be too large is a factor to control the frequency of switching between routes
IV. Simulation Result(1/3) • CBR • UDP • FTP • TCP
V. Conclusion • End-to-end delay • Network resource
Future Work • Study of optimal load balancing scheme • QoS support in MSR