Understanding risk for network resilience Paul Smith, Marcus - - PowerPoint PPT Presentation

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Aug 10, 2023 135 likes •239 views

Understanding risk for network resilience Paul Smith, Marcus Schoeller (NEC), and David Hutchison p.smith@comp.lancs.ac.uk Multi-service Networks July 2009 What is network resilience? The ability of a networked system to provide an

SLIDE 1

Understanding risk for network resilience

Paul Smith, Marcus Schoeller (NEC), and David Hutchison p.smith@comp.lancs.ac.uk Multi-service Networks July 2009

SLIDE 2

What is network resilience?

The ability of a networked system to provide an

acceptable level service in light of challenges

Challenges
Component faults
Hardware destruction
Human mistakes
Malicious attacks
....

SLIDE 3

Nothing comes for free

Providing network resilience has a cost
We need systems to do this
We are resource constrained
$£€, cpu cycles, bandwidth

SLIDE 4

Need to prioritise and focus efforts

All challenges Most probable high-impact challenges

SLIDE 5

Identifying critical challenges

Identify critical assets Determine cost of asset compromise Develop system understanding Identify challenges to the system Identify system faults Identify probability of failure 1 2 3 4

Determine measure of exposure

5 6 7

exposure = cost x probability

SLIDE 6

What’s difficult about this?

Determining reliable measures for

challenge occurrence probabilities [and the probability of that leading to failure]

Quantifying the impact of a challenge

SLIDE 7

Challenge: Getting reliable numbers

Off-line analysis
Advisories are useful (e.g., www.cert.org)
Fault and attack tree analysis
Issues of scalability because of complexity
Simulation
Need to develop good challenge and fault models
Record monitoring data from on-line system
Classify challenges using machine learning
Introduces resource and security concerns

SLIDE 8

Need for on-line impact measures for automated mitigation

Detect Identify Determine Impact Mitigate Symptoms Understand

E.g., Monetary cost resource utilisation Effect on other services Loss of data

E.g., Service failures Network congestion Poor performance Anomalous traffic. Detection of symptoms Understand challenge root cause

SLIDE 9

Conclusions

To make best use of limited resources, we need

to determine the high-impact challenges

Getting good numbers for challenge probabilities

and their impact is hard

Some on-line components necessary, which has

implications on system design

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