University of Illinois at Urbana-Champaign

1. Fault-Tolerant Routing • Observation • High Redundancy • Problem • Trade-off between packet delivery ratio and overhead Possible Approaches • Isolation • Authentication infrastructure • Intrusion detection • Toleration • Route the packets in the presence of misbehaving nodes • Misbehavior Assumptions • Byzantine faulty behavior in routing and forwarding • No denial of service attack to the MAC/physical layer Providing Fault-Tolerant Ad-hoc Routing Service in Adversarial Environments Yuan Xue and Klara Nahrstedt Motivation when misbehaving nodes exist in ad hoc networks, the performance of its routing protocols will significantly degrade. www.iti.uiuc.edu I: percentage that network has a “good” path II: percentage that DSR route protocol discovers a “good” path III:percentage that DSR uses a “good” path I N F O R M A T I O N T R U S T I N S T I T U T E University of Illinois at Urbana-Champaign

2. Strategies Assume bad, until confirmed good Assume good, until confirmed bad Best-effort FT Routing Assured FT routing Algorithm Algorithm Start with the shortest path Hypothesis test Discard the bad path Proceed with next shortest path • Start with all available paths • Refine the route progressively • Drop unnecessary path • Confirm a good path Property Property Lower bound on packet delivery ratio Upper bound on overhead Upper Bound on false positive probability Lower Bound on packet delivery ratio Providing Fault-Tolerant Ad-hoc Routing Service in Adversarial Environments Yuan Xue and Klara Nahrstedt • Method end-to-end performance measurement • Security Assumptions • Source and destination are well-behaved nodes • Priori trust relationship between source and destination www.iti.uiuc.edu I N F O R M A T I O N T R U S T I N S T I T U T E University of Illinois at Urbana-Champaign

3. DSR AFTR BFTR Multipath • Acknowledgement • ONR MURI CU fund • Professor Nitin Vaidya and Pradeep Kyasanur for their comments and helpful suggestions Providing Fault-Tolerant Ad-hoc Routing Service in Adversarial Environments Yuan Xue and Klara Nahrstedt Results 1.1 1 0.9 0.8 Greatly improved packet delivery ratio Controlled Overhead Packet delivery ratio 0.7 0.6 0.5 0.4 0 10 20 30 40 percent of misbehaving nodes Conclusion Fault tolerant routing is an efficient and effective approach to address the problem of misbehaving nodes in ad hoc networks www.iti.uiuc.edu I N F O R M A T I O N T R U S T I N S T I T U T E University of Illinois at Urbana-Champaign