Tracing Selfish Nodes

1. Tracing Selfish Nodes Jiangyi Hu Florida State University

2. Outline • Introduction • Requirements to enforce cooperation • Mechanisms to enforce cooperation • Virtual currency systems • Reputation based systems • Tracing selfish nodes Tracing Selfish Nodes

3. Introduction An example of Mobile Ad hoc networks C F B A D E Tracing Selfish Nodes

4. Introduction Characteristics of MANETs: • Wireless connection, broadcast • Dynamic topology • Unfriendly environment • Nodes with limited resource Tracing Selfish Nodes

5. Requirements to Enforce Cooperation • Regular functions of a MANETare based on node cooperation. • Routing protocols for MANETs assumethat all nodes cooperate. • However, the reality is • Nodes have limited resource, service provision is not in the interest of the nodes. • Nodes are owned by different entities. • Cooperation cannot be taken for granted. Tracing Selfish Nodes

6. Selfish Nodes • Do not directly perform any action to compromise network integrity. • Do not perform certain operations due to selfishness (e.g. to preservepower). • Selfishness is an uncooperative behavior. • the main threatfrom selfish nodes is packet dropping. Tracing Selfish Nodes

7. Mechanisms to enforce cooperation • Virtual currency systems • Use credit or micro payments to compensate for the service of a node. • Examples: • Nuglets • Sprite • Reputation systems • Rely on neighbor monitoring to dynamically assess the trustworthiness of nodes. • Examples: • CORE • CONFIDANT Tracing Selfish Nodes

8. Detection of misbehavior • Tracing Byzantine faults(B. Awerbuch, D. Holmer, C. Nita-Rotaru and H. Rubens, An On-Demand Secure Routing Protocol Resilient to Byzantine Failures) • Detects misbehavior and locates the fault to two adjacent nodes. • Discovers misbehavior based on acknowledgment of the data packets. • Uses a divide-and-conquer strategy to locate fault. • Determines the fault location in log(n) round. Tracing Selfish Nodes

9. Tracing Selfish Nodes

10. Detection of Misbehavior • Secure Communication Protocol (Mike Burmester and Tri van Le, Secure Communication in MANETs) • Detects misbehavior and locates the fault to two adjacent nodes. • Relies on the acknowledgements. • Determines the fault location inone round. Tracing Selfish Nodes

11. Detection of Misbehavior M is a malicious node and dropped the packet. • Case1: B send nackBto S • Case 2: M send nackM to S S B M C D S B M C D Tracing Selfish Nodes

12. S-A-B-D S-A-B-D S-A-B-D S-A S S-A-B S-C-E S S-C-E S-C-E S-C DSR - Dynamic Source Routing A D B S S-C-E-H S-A-B H E S-C-E-H S-C-E-F C F Tracing Selfish Nodes

13. DSR with selfish nodes S B M C D Tracing Selfish Nodes

14. Tracing selfish nodes • S:the source • D:the destination • I:an intermediate node • N(X): one-hop neighbor of node X • When Ireceives a packetoriginated from S, it transmits the packet • Each node X, X N(I), will keepa record of the packet sent by I Tracing Selfish Nodes

15. Tracing selfish nodes • If succeeds, D returns anacknowledgement back to S • otherwise, S sends atrace packet • N(I)will participate in the trace process to identify the selfish node • If I forwarded the packet, N(I) have records • If I dropped the packet,N(I) have no record Tracing Selfish Nodes

16. Tracing selfish nodes S I M L D : Forwarding : Connected through multi-hops : trace Tracing Selfish Nodes

17. Tracing selfish nodes Optimization: • Only one neighbor needs to transmit a record. • Only record from the highestupstream node is transmitted. Tracing Selfish Nodes

18. Tracing selfish nodes • Decentralized • No false accusation • Reduced overhead Tracing Selfish Nodes

19. Thank You! Tracing Selfish Nodes