Providing Fault-Tolerant Ad-hoc Routing Service in Adversarial Environments
Yuan Xue and Klara Nahrstedt
Fault-Tolerant Routing
Motivation when misbehaving
nodes exist in ad hoc networks, the
performance of its routing protocols
will significantly degrade.
Observation

High Redundancy
Problem
Trade-off between packet
delivery ratio and overhead

Possible Approaches
Isolation
Authentication infrastructure
 Intrusion detection

Misbehavior Assumptions
Toleration
Route the packets in the presence
of misbehaving nodes

INFORMATION TRUST INSTITUTE
University of Illinois at Urbana-Champaign
Byzantine faulty behavior in routing and
forwarding
• No denial of service attack to the
MAC/physical layer
•
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
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
Strategies
Assume bad, until confirmed good
Assume good, until confirmed bad
Assured FT routing
Algorithm
Start with all available paths
Refine the route progressively
 Drop unnecessary path
 Confirm a good path
Best-effort FT Routing
Algorithm
Start with the shortest path
Hypothesis test
Discard the bad path
Proceed with next shortest path
Property
Property
Lower bound on packet delivery ratio
Upper bound on overhead
INFORMATION TRUST INSTITUTE
University of Illinois at Urbana-Champaign
Upper Bound on false positive probability
Lower Bound on packet delivery ratio
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Providing Fault-Tolerant Ad-hoc Routing Service in Adversarial Environments
Yuan Xue and Klara Nahrstedt
1.1
Results
Greatly improved packet delivery ratio
Controlled Overhead
Packet delivery ratio
1
0.9
0.8
0.7
DSR
AFTR
BFTR
Multipath
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
Acknowledgement
• ONR MURI CU fund
• Professor Nitin Vaidya and Pradeep Kyasanur for their comments and helpful suggestions
INFORMATION TRUST INSTITUTE
University of Illinois at Urbana-Champaign
www.iti.uiuc.edu