Diversity Diversity Michele Morganti 2 nd ReSIST Open Workshop 18 - - PDF document

Resilience in Computing Systems and Information Infrastructures: A Research Agenda

Diversity Diversity

Michele Morganti

2nd ReSIST Open Workshop –18 October 2007 – Rome, Italy

About D13 Diversity at large

Deliverable D13 - From Resilience-Building to Resilience- Scaling Technologies: Directions on Diversity ! Good analysis and assessment ! Valuable conclusions and directions for future research ! Following comments/observations intended solely as contributions to reasoning/discussion ! No implicit or explicit criticism

10/22/2007 2

D13

Unforeseen events vs. Unavoidable changes

10/22/2007 3

Diversity Adverse events

• extreme, catastrophic
• rare, unlikely
• correlated, insider
• . . .

Robustness Continuous evolution

• context
• technology
• size
• . . .

Adaptability Where did complexity end up ? Security vs. Survival

10/22/2007 4

Hostile attacker

• enemy
• terrorist
• vandal
• . . .

Mike’s paradox: “Whatever the choice, Resilience is in the other”

Gold Gold Pot Pot

Cup Cup Gold Gold Gold Gold Cup Cup

Malicious attacker

• thief
• spy
• . . .

Gold Gold Pot Pot

Diversity vs. Redundancy

10/22/2007

Fault-Tolerance vs. Performance, Coverage, …

Fault

Survival with some Degradation

High Performance / Low Resilience Low Performance / High Resilience

Structural vs. Infrastructural In-built vs. Outsourced Systems vs. Services Redundancy vs. Multiplicity

Fault

Continuity without Degradation

In-built systems vs. Outsourced services

10/22/2007 6

2G 3G BWA 2G 3G BWA

NGN Operator A MN Operator B FN Operator C Service Provide X Service Provide Y

Hot-

• Spot

W-LAN GSM-R TETRA Ad-Hoc Public Networks Private and Ad-hoc Networks to Public Networks

Same basic functions but totally different characteristics

D13

Space vs. Time related Diversity

10/22/2007 7

Diversity Space related

• replication
• segmentation
• . . .

Interoperability

(horizontal & vertical)

Time related

• expansion
• evolution
• . . .

Compatibility

(backward & forward)

A different focus/role for standards ?

Architectures with explicit redundancy

10/22/2007 8

Suggested fully redundant GSM-R architecture

(Fully duplicated network structure with overlayed radio cells)

VLR HLR AC VLR HLR AC BSC BSC BTS BTS BTS BTS BTS BTS BTS BTS

OMC MSC OMC MSC

Can we quantify diversity pro/con tradeoffs ?

Architectures without explicit redundancy

10/22/2007 9

BTS

SIM

MS BSC MSC BSC VLR OMC NMC HLR EIR MSC AC

PSTN

SGSN GGSN

PDN

GSM/GPRS Reference Architecture

Time related diversity is unavoidable in complex, long lasting systems