Self-stabilizing energy-efficient multicast for MANETs

1. Self-stabilizing energy-efficient multicast for MANETs

2. Mobile Ad hoc Networks (MANETs) Network Model • mobile nodes (PDAs, laptops etc.) • multi-hop routes between nodes • no fixed infrastructure Applications • Battlefield operations • Disaster Relief • Personal area networking Multi-hop routes generated among nodes Network Characteristics • Dynamic Topology • Constrained resources • battery power B C A C A B D D Links formed and broken with mobility

3. Self-stabilization in Distributed Computing Topological Changes and Node Failures for MANETs. Self-stabilizing distributed systems • Guarantee convergence to valid state through local actions in distributed nodes. • Ensure closure to remain in valid state until any fault occurs. Can adaptto topological changes • Is it feasible for routing in MANETs? Fault Closure Invalid State Valid State Convergence Local actions in distributed nodes. Applied to Multicasting in MANETs

4. Self-stabilizing Multicast for MANETs Multicast source Topological Change • Maintains source-based multi-cast tree. • Actions based on local information in the nodes and neighbors. • Pro-active neighbor monitoring through periodic beacon messages. • Neighbor check at each round (with at least one beacon reception from all the neighbors) • Execute actions only in case of changes in the neighborhood. Convergence Based on Local actions Self-Stabilizing Shortest Path Spanning Tree (SS-SPST)

5. Self-stabilizing Multicast Tree Construction • Arbitrary Initial State – no multicast tree • Parent of each node NULL. • Level of each node 0. S A B • First Round – source (root) stabilizes • level of root is 0. G C D H • Second Round – neighbors of root stabilizes • level of root’s neighbors is 1. • parent of root’s neighbors is root. I J E F • And so on …… SS-SPST • Pruning of the tree in a bottom-up manner. Problem – energy-efficiency is not considered • Tolerance to topological changes.

6. Energy-Efficiency in Self-stabilization

7. j k i Ti l i non-intended neighbor Ti reaches all nodes in range Energy Consumption Model Ci = Ti+NixR Cost metric for node i Transmission energy of node i Reception cost at all the neighbors • Variable through Power Control • One transmission reaches all in range • Reception energy at intended neighbors. • Overhearing energy at non-intended neighbors. intended neighbor No communication schedule during broadcastin random access MAC (e.g. 802.11). Overhearing at j, k, and l Ci = Ti + 7R What is the additional cost if a node selects a parent?

8. Energy Aware Self-Stabilizing Protocol (SS-SPST-E) • Actions at each node • (parent selection) • Identify potential parents. • Estimate additional cost after joining potential parent. • Select parent with minimum additional cost. • Change distance to root. Loop Detected E Not in tree F A B D C X AdditionalCost (B → X) = TB + R AdditionalCost (A → X) = TA + 2R Potential Parents of X • Action Triggers • Parent disconnection. • Parent additional cost not minimum. • Change in distance of parent to root. Select Parentwith minimum Additional Cost Minimum overall cost when parent is locally selected Execute action when any action trigger is on • Tree validity– Tree will remainconnected • withno loops.

9. SS-SPST-E Execution Multicast source • No multicast tree • parent of each node NULL. • hop distance from root of each node infinity. • cost of each nodeis Emax. 2 2 A S B 1 2 2 G 3 1 No potential parents for any node. • First Round – source (root) stabilizes • hop distance of root from itself is 0. • no additionalcost. 1 D C H 2 2 • Second Round – neighbors of root stabilizes • hop distance of root’s neighbors is 1. • parent of root’s neighbors is root. Potential parent forA, B, C, D, F={S}. E F 2 AdditionalCost (F → E) = TF + 2R AdditionalCost (D → E) = TD + 3R AdditionalCost (S → {A, B, C, D}) = Ts + 4R AdditionalCost(D → E) = TD + 3R • And so on …… Potential parent forE={D, F}. AdditionalCost (S → F) = TS + 5R AdditionalCost (C → F) = TC + 3R AdditionalCost (S → F) = Ts + 5R Potential parent forF= {S,C}. • Tolerance to topological changes. • Convergence- From any invalid state the total energy cost of the graph reduces afterevery roundtill all the nodes in the system are stabilized. • Proof - through induction on round #. • Closure:Once all the nodes are stabilized it stays there untilfurther faultsoccur.

10. Simulation Results – Varying Beacon Interval Energy consumption per packet delivered increases due to decrease in number of packets delivered.

11. Simulation Results – Varying Beacon Interval PDR decreases with less beaconing What is the optimum beacon interval?

12. Improvements to self-stabilizing multicast • Fault-localization to reduce stabilization time • Incorporate fault-containment mechanism • Optimize the beacon interval to minimize overhead energy • depends on data traffic arrival • depends on changes in link status • depends on what level of reliability to attain • Management plane required at the network layer to control protocol parameters

13. Application-aware Adaptive Optimization Sub-layer

14. Sample Result

15. Additional Slides

16. Simulation Results – Varying Node Mobility 10m/s 15m/s 20m/s 5m/s 1m/s Low packet delivery with high dynamicity ODMRP has high PDR due to redundant routes

17. Simulation Results – Varying Node Mobility 1m/s 5m/s 10m/s 15m/s 20m/s SS-SPST-Eleads to energy-efficiency ODMRP has high overhead to generate redundant routes

18. Simulation Results - Varying Multicast Group Size 40 10 20 30 50 Self-stabilizing protocols scale better. MAODV has highest delay due to reactive tree construction