1. A Preferred Link Based Multicast Protocol for Wireless Mobile Ad hoc Networks R. S. Sisodia, Karthigeyan. I, B. S. Manoj, and C. Siva Ram Murthy ICC 2003

2. Outline  Introduction  Multicast Tree  Preferred Link Based Algorithm  Tree Maintenance  Performance  Conclusions

3. Introduction  Existing multicast routing protocols can be broadly classified into two categories Tree based protocols Mesh based protocol  Mesh based protocols have high packet delivery ratio compared to tree based protocols More control overhead JoinQuery packets

4. Introduction (cont.)  This paper propose an efficient protocol Preferred Link Based Multicast protocol (PLBM)  Uses a preferred link approach for forwarding JoinQuery packets Restricts the flooding of JQ packets  Preferred link based algorithm Preferred nodes  Locally repairs broken links The local two hop network topology

5. Multicast Tree  Tree nodes Multicast source Connected member nodes Forwarding nodes  Neighbors Neighbors Table (NNT)  Connect Table (CT)

6. Multicast Tree (cont.)

7. Preferred Link Based Algorithm  The PLBA Preferred links (nodes) Utilizes the two hop topology information  NNT A E D C B C E Preferred node

8. Preferred Link Based Algorithm (cont.)  Condition 1 The current forwarding node excludes all its neighbors that have already forwarded JQ A BC JQ D E

9. Preferred Link Based Algorithm (cont.)  Condition 2 The current forwarding node is prevented from forwarding JQ to those neighbors that are shared by the nodes A BC D

10. Preferred Link Based Algorithm (cont.)  Condition 3 Prevents broadcast to those nodes that are neighbors of nodes in the traversed path of JQ A BC D D

11. Preferred Link Based Algorithm (cont.)  Example

12. Preferred Link Based Algorithm (cont.)  Example

13. Tree Maintenance PACKET_AWAIT_TIMER

14. Performance  GloMoSim  Simulation Area 1000X1000 m  The simulation is run for 600 seconds  Transmission Rage 250m  Nodes 50  PACKET_AWAIT_TIMER 1 sec

15. Performance (cont.) Group size 20

16. Performance (cont.) Mobility 9 m/s

17. Conclusions  An efficient receiver-initiated tree based multicast protocol Preferred link based approach  Dominating set