2. Peter Pham and Sylvie Perreau, IEEE 2002 Mobile and Wireless Communications Network Multi-Path Routing Protocol with Load Balancing Policy in Mobile Ad Hoc Network Speaker : Wilson Lai Date : 92.02.20

3. Outline Motivation Proposed Routing Method Result and analysis Conclusion Question & Discussion My research

4. Motivation Multi-path routing to provide improved throughput and route resilience as compared with single-path routing in wired network. In the most multi-path routing protocols, the traffic is distributed mainly on the primary route. It is only when this route is broken that the traffic is diverted to alternate routes. Load-balancing is not achieved. There is a demand for multi-path routing strategy not only efficiently can balance the load but also cope with the dynamics of the network MRP-LB is based on the combination.

5. Multi-path Routing Find multiple path in route discovery Use one or several paths to forward data packets If one path fails, switch to another one If all path fails, start route recovery

6. Multi-path DSR Based on DSR During discovery phase, destination send multiple link-wise disjoint paths in RREP Initially send data packet along primary path During maintenance phase, when primary path fails, switch to a shortest alternative path

7. Overview of DSR S D A B C E F G s s sa sb sbeg sbef sbe sac sacd

8. Multi-path of DSR S D A B C E F G s s sa sb sbeg sbef sbe sac sacd sbefd

9. Route Discovery (1/2) The source sends request packets (REQs) to the destination to discover multiple routes. The target host replies a maximum of Nu request packets with Nu reply packets (REPs)

10. When forwarding the REPs, intermediate nodes record their congested packets, compute total number of congested packets on the route and store it on the field Total Congested Packets inside the REPS. By the end of Route Discovery phase, Nu routes are discovered. Route Discovery (2/2)

11. Data Transmission It chooses a route in accordance with the following criteria :

12. Route Maintenance Every node sent periodic “Hello” messages to its neighbor to keep track of the connectivity between them, and maintain count-down timers for each neighbor. The “Hello” message consists of the source node ID to help neighbors to identify the source. Link breakage is detected when a node does not receive a “Hello” message or a data packet from its neighbor for a TIME_OUT period.

13. After the Route Discovery phase, the source node has the current information about the load on each route. This information may not be accurate in later stage since nodes along the routes are processing packets with different rate. The source has up-to-date information about the load on the routes, destination periodically sends Load Packets (LPs) to the source. Load Balance Maintenance

14. Simulation parameters Typical network size: 40 nodes Typical area size: 1500X1500 m 2 Transmitter range: 250 m Channel bandwidth: 2 Mb Packet size: 512B (4 packet per sec per conn.) Mac protocol: CSMA (IEEE 802.11) Maximum of multi-path : 3 paths Mobility : adjustable as user

15. Result and analysis (1/3)

16. Result and analysis (2/3)

17. Result and analysis (3/3) 3 routes Hello LP

18. Conclusion The important features of MRP-LB are maintaining multiple routes for each source – destination pair and spreading data traffic evenly onto these routes. MRP-LB outperforms DSR in terms of packet delivery ratio and average end-to-end data packet delay. It has higher overheads than DSR which serves as a price for higher efficiency and packet delay.

19. Question & Discussion Data packets are likely to arrive out of order since they are sent on different paths and experience of different delay. –This inevitably affects the performance of TCP. Mobility be ignored. –There are some doubt about the simulation results.

20. Reference for route discovery N i (i=1:N) denotes the mobile nodes S ij denotes the sequence number corresponding to node N i and N j N u is the maximum number of multiple routes that we want to discover

21. Reference for data transmission Each source records number of packets sent on each route, in a Packet Sent Table.