University of Illinois at Urbana-Champaign

www.iti.uiuc.edu

Providing Fault-Tolerant Ad-hoc Routing Service in Adversarial EnvironmentsYuan Xue and Klara Nahrstedt

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

Motivation when misbehaving nodes exist in ad hoc networks, the performance of its routing protocols will significantly degrade.

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

I: percentage that network has a “good” pathII: percentage that DSR route protocol discovers a “good” pathIII:percentage that DSR uses a “good” path

Fault-Tolerant Routing

Observation High Redundancy

Problem Trade-off between packet delivery ratio and overhead

University of Illinois at Urbana-Champaign

www.iti.uiuc.edu

Providing Fault-Tolerant Ad-hoc Routing Service in Adversarial EnvironmentsYuan Xue and Klara Nahrstedt

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

Strategies Assume bad, until confirmed good Assume good, until confirmed bad

Method end-to-end performance measurementSecurity Assumptions• Source and destination are well-behaved nodes• Priori trust relationship between source and destination

Assured FT routing

Start with all available paths Refine the route progressively Drop unnecessary path Confirm a good path Lower bound on packet delivery ratio Upper bound on overhead

Algorithm

Property

Best-effort FT Routing

Property

Algorithm Start with the shortest path Hypothesis test Discard the bad path Proceed with next shortest path

Upper Bound on false positive probability Lower Bound on packet delivery ratio

University of Illinois at Urbana-Champaign

www.iti.uiuc.edu

Providing Fault-Tolerant Ad-hoc Routing Service in Adversarial EnvironmentsYuan Xue and Klara Nahrstedt

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

Results

Greatly improved packet delivery ratio Controlled Overhead

Conclusion Fault tolerant routing is an efficient and effective

approach to address the problem of misbehaving nodes in ad hoc networks

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Acknowledgement• ONR MURI CU fund• Professor Nitin Vaidya and Pradeep Kyasanur for their comments and helpful suggestions