Cooperation Of Nodes: Fairness In Dynamic Adhoc NeTworks CONFIDANT

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Cooperation Of Nodes Fairness In Dynamic Ad-hoc
NeTworks (CONFIDANT)?

• Thomas Belote
• CS297 presentationfor CS258
• Fall 2007
• SJSU

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Wireless Mesh Networking and Mobile Ad-hoc
NETworks

• A routing protocol
• Self-Organizing
• Robust to failures and node mobility
• Nodes are routers and infrastructure

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Reputation Systems

• What systems do you already know about?
• How do they work?
• Ebay
• Amazon
• Credit Score
• School GPA
• Job References

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Goals of CONFIDANT

• Detect, prevent, and/or discourage
• No forwarding (of control messages or data)?
• Traffic deviation
• Advertise many routes
• Advertise routes too often
• Advertise no routes
• Route salvaging, rerouting to avoid a broken
  although no error has been observed
• Lock of error messages, although an error has
  been observed (and vice versa)?
• Silent route change (tampering with message
  headers of either control or data packets)?

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Reputation Systems response to Attacks

• A different method to handling attacks is to
  prevent them
• Only allow good nodes onto the network
• Secure key to access network
• Reputation systems detect misbehavior and then
  try to thwart attacks.
• A good idea even if other methods have been used
  to prevent attacks and secure access

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CONFIDANT built on top of DSR

• Dynamic Source Routing (DSR)?
• Reactive/On-Demand routing
• Nodes send a ROUTE REQUEST message
• Neighbors add themselves to the source route and
  forward it on
• If the receiving node is the destination or has a
  route to the destination it sends a REPLY message
  with the full route
• First received ROUTE REPLY wins
• Failed links can be salvaged by partial alternate
  route
• Routes are cached for some period of time

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CONFIDANT Protocol

• Observed Behavior
• 'Neighborhood Watch' behavior that is directly
  observed, overheard, by the node.
• Reported Behavior
• Share experienced misbehavior and learn from
  friends.

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CONFIDANT Inspiration

• Richard Dawkin's The Selfish Gene
• Suckers
• Cheats
• Grudgers

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CONFIDANT Components

• The Monitor
• Directly observes behavior
• The Trust Manager
• Sends and receives ALARMs
• The Reputation System
• Node Rating
• The Path Manager
• Route management based on Reputation
• (Every nodes implements all of these components)?

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The Monitor

• Directly observes behavior
• no forward (only observation implemented in this
  simulation)?
• Packet alteration
• Data packets
• Routing packets
• Consistent claim of neighboring nodes
• Any other observable metric

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The Trust Manager

• Generate an alarm on experienced or observed
  misbehavior.
• Forward alarm on received report of misbehavior.
• Maintain trust table to determine trustworthiness
  of alarm
• Determining trust level algorithm is an open
  question in paper

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The Reputation System

• Table of nodes and their rating.
• Weighted between past rating and newly observed
  behavior and reported reputation.
• Only negative experience is counted
• Positive change and timeout are not addressed
  yet.
• Assume negative behavior is rare, and probably
  means node can never be trusted.

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The Path Manager

• Path re-ranking according to security metric
  (re-rank route based on reputation).
• Deletion of paths containing malicious nodes.
• Action on receiving a request for a route from a
  malicious node (ignore request).
• Action on receiving request for a route
  containing a malicious node in the source route
  (ignore, alert source).

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CONFIDANT Components
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Metrics
Goodput
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Confidant Experimental Setup
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Confidant Results
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Confidant Results
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Confidant Results
Figure 4 Number of packets dropped per number of
packets sent by 50 nodes, one third malicious,
30 applications, 20 simulation runs.
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References

• Buchegger, S. and Le Boudec, J. 2002. Performance
  analysis of the CONFIDANT protocol. In
  Proceedings of the 3rd ACM international
  Symposium on Mobile Ad Hoc Networking Amp
  Computing (Lausanne, Switzerland, June 09 - 11,
  2002). MobiHoc '02. ACM, New York, NY, 226-236.
  DOI http//doi.acm.org/10.1145/513800.513828