Analysis of a given synchronisation protocol

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Analysis of a given synchronisation protocol

• Rain Ottis

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Overview

• Introduction
• Protocol overview
• Step 1 static system analysis
• Step 2 exhaustive analysis
• Step 3 dynamic analysis
• Summary

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Introduction

• Analyse the correctness and behavior of given
  synchronisation protocol in different error
  situations
• ... using simulation?
• Node failures, connection failures
• Protocol not yet implemented

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Protocol overview
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Step 1 static system analysis

• Assume server/connection is up or down for the
  test period
• Three servers need to be connected to at least
  one client 24 combinations
• Results (no errors in 10 years)
• Server downtime 29 min/year Connection failure lt
  0.99
• Server downtime 0 min/year Connection failure lt
  3.82
• Polynomial formula

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Protocol implementation plan
Sync Server
Hasher 2
Hasher 1
Hasher 1
Hasher 2
Client
Client
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Step 2 exhaustive analysis

• Modified system structure (three server nodes,
  two clients)
• One request iteration
• What are the conditions for system failure based
  on message loss
• Failure client receives Error message or request
  times out
• Assumes that client-hasher connection works

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Step 3 dynamic analysis

• Simulation of the system using dynamically
  changing variables
• May identify cases that were not considered
  before

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Summary

• Goal to identify any weaknesses in the
  synchronisation protocol
• Static analysis
• Exhaustive analysis
• Dynamic analysis

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Questions?