Understanding Challenges and their impact on network resilience - PowerPoint PPT Presentation

Understanding Challenges and their impact on network resilience Marcus Schöller Paul Smith NEC Europe Laboratories Lancaster University Datum

Motivation and Overview  Goal: Determine high impact challenges  Add defensive and remediation mechanisms  Meet cost constraints  Challenges  Component Faults  Hardware destruction  Challenges to the communication environment  Human Mistakes  Malicious attacks from intelligent adversaries  Unusual but Legitimate Demand for Service  Failure of a Provider Service  Case Study to exemplify 2 M. Schöller, P. Smith Dagstuhl Seminar, 14-17 April 2009

The community mesh network in Wray  Single back-haul link  Mesh gateway at school  Upstream provider: Uni Lancaster  802.11b mesh  Currently hard coded routes  Network services  DNS, DHCP, NAT and FW  Secondary DNS at Uni Lancaster 3 M. Schöller, P. Smith Dagstuhl Seminar, 14-17 April 2009

Identify critical assets and their value  End Users  Value  Internet Connectivity  Loss depends on state  Safety: of less computer literate members, of impairment personal identity, reputation, protection of  Three-level state space children  Acceptable  Security: documents, photos, …  Impaired  Operator  Unacceptable  Physical Infrastructure  Assign impact value  Security of services incl. charging [0:1]  Connectivity: SLAs, QoS , …  Researchers  Monitoring of network  Measurements on network 4 M. Schöller, P. Smith Dagstuhl Seminar, 14-17 April 2009

System, challenges, and faults • 1. System understanding Challenges in Wray  Software engineering • Milk Truck 2. Identify potential challenges to the • Extreme Weather system • Device mis-configuration Learning from past events  • Broken hardware - Advisories on past resilience • Mis-use of resources incidence •  System analysis Malware - Fault Tree - Event and attack tree 3. System faults Connecting challenges and system  components  Taxonomy 5 M. Schöller, P. Smith Dagstuhl Seminar, 14-17 April 2009

Challenge Sheets for documentation Challenge Name Frequency Jammer Classification Category Malicious Attack Scenario Wireless Communication Characteristics Description The frequency used for communication is jammed by a) constant, b) periodic, c) interactive, d) arbitrary transmissions of the attacker. Scope MAC Potential Impact Communication among nodes in the vicinity is prevented or severely degraded Details Parameters Duration of interference, period of jamming signal, output signal strength Symptoms MAC layer protocol violation, disrupted link frames, reduced link bandwidth 6 M. Schöller, P. Smith Dagstuhl Seminar, 14-17 April 2009

Determine a measure of exposure 1. Likelihood of challenge degrading a service  Three-level state space 2. Impact costs  Derived from asset values 3. Calculate exposure Impact Cost * likelihood  Order challenges based on  exposure 4. Adding defensive and remediation mechanisms Cost constrainted  7 M. Schöller, P. Smith Dagstuhl Seminar, 14-17 April 2009

Summary and Open Questions  Reliable measures for challenge occurrence probabilities  Analyzing monitoring data  Online documentation of adaptation cycles  Machine learning on dataset  Information sharing to system engineers is difficult  Quantifying the impact of a challenge  Understand challenges parameters  Build challenge simulation models to run against system models incl. fault models  Advise to system monitoring engineering  Monitoring of network metrics based on symptoms of most probable challenges 8 M. Schöller, P. Smith Dagstuhl Seminar, 14-17 April 2009

Thank you for your attention 9 Datum