POLICY CONFLICT ANALYSIS FOR QUALITY OF SERVICE MANAGEMENT

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POLICY CONFLICT ANALYSIS FOR QUALITY OF SERVICE
MANAGEMENT

• Marinos Charalambides, Paris Flegkas, George
  Pavlou
• CCSR, University of Surrey, UK
• Arosha K Bandara, Emil C Lupu, Alessandra Russo,
  Naranker Dulay, Morris Sloman
• Department of Computing, Imperial College London,
  UK
• Javier Rubio-Loyola
• Teoria del Senyal i Comunicacions, Universitat
  Politecnica de Catalunya, Spain
• POLICY 2005 6-8 June 2005
• Stockholm, Sweeden

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Talk Outline

• MOTIVATION
• NETWORK DIMENSIONING
• ND POLICY CONFLICTS
• CONFLICT ANALYSIS
• SUMMARY
• FUTURE DIRECTIONS

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Motivation

• QoS MANAGEMENT THROUGH POLICIES

• THE NEED FOR CONFLICT ANALYSIS
• Detect inconsistencies in policy specification
• Resolve potential conflicts before enforcement

• THE TEQUILA FRAMEWORK
• QoS management for DiffServ networks
• Policy-driven architecture

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Policy Conflicts

• WHAT IS A CONFLICT?
• MODALITY CONFLICTS
• Same subjects and targets
• Actions of opposite modality
• APPLICATION-SPECIFIC CONFLICTS
• When two rules contradict each other due to the
  context of the application
• Examples conflicts of duty, interest, multiple
  manager conflicts
• ND CONFLICTS
• Domain-independent / application-specific
  conflicts

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Network Dimensioning (1/2)

• FUNCTIONALITY
• Static, off-line resource management component
• Mapping traffic forecast requirements onto
  physical resources
• Long to medium term network configuration
• POLICIES FOR ND
• Route setup and BW allocation
• Hop count derivation
• Optimisation algorithm
• Spare/overprovisioned BW treatment
• POLICY REPRESENTATION

oblig /policies/nd/PolA on doNDProc
subj s ndPMA targ t nd/baMO/network
do t.setBWMin(ef, 40) when ltconstraintsgt
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Network Dimensioning (2/2)

• EVENTS
• Pre-processing
• Processing
• Post-processing

M2
M3
M4
M1
M5
M6
M7
M8
Methods M5 setBWMin(ef, 40)
M9
M10
M11
M13
M12
M14
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ND Policy Conflicts (1/2)

• CONFLICT CLASSIFICATION
• Domain-independent conflicts
• Application-specific conflicts

do t.setBWMax(ef, 40) do t.setBWMax(ef,
30)
Redundancy Mutual Exclusion
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ND Policy Conflicts (2/2)

• CONFLICTING POLICIES
• raConflict/baConflict/bwExceedConflict
• raConflict/baConflict/divActionsConflict
• raConflict/routingConflict
• raConflict/barConflict

do t.allocSpareBWExpl(ef, BW1) do
t.allocSpareBWExpl(af, BW2) do
t.allocSpareBWExpl(be, BW3)
do t.setMaxHops(ef, HopNum) do
t.setupLSP(ef, TT, PATH, BW)
do t.setBWMax(ef, BW1) do t.setupLSP(ef,
TT, PATH, BW2)
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Conflict Analysis (1/2)

• ANALYSIS FRAMEWORK
• Policy specification using Ponder
• Behavioural model of managed objects (state
  charts)
• Organisational model of managed objects (domain
  hierarchy)
• Formal representation using Event Calculus

• SYSTEM ARCHITECTURE

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Conflict Analysis (2/2)

• DETECTION LOGIC
• Detection rules
• Conflict predicates

holdsAt(dvrgActionsConflict(PolID1, PolID2,
BW1,BW2), T) ? holdsAt(oblig(PolID1, Subj,
operation(Targ1, setBWMin(OA1, BW1))), T) ?
holdsAt(oblig(PolID2, Subj, operation(Targ2,
setBWMax(OA2, BW2))), T) ? OA1 OA2 ? BW1 gt
BW2 ? Targ1 Targ2.
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Detection Example

• DETECTION TOOL
• Conflict fluent as a goal state of a query
• Deduction for simple rule matching
• Abductive reasoning for constraints

?- solve(conflict(Type, ConflictData, T)). 0
happens(clocktick(16, 0, 0), 0) 1
happens(clocktick(18, 0, 0), 1) 2
happens(clocktick(20, 0, 0), 2) conflict(dvrgActi
onsConflict, conflictData(p1, p2, 50, 40), 1)
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Summary

• POLICIES FOR NETWORK DIMENSIONING
• CONFLICT IDENTIFICATION AND CLASSIFICATION
• CONFLICT DETECTION RULES
• EVENT CALCULUS FOR CONFLICT ANALYSIS
• TOOL SUPPORT

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Future Directions

• CLASSIFICATION AND DETECTION OF INTRA-COMPONENT
  CONFLICTS RELATED TO OTHER TEQUILA MODULES
• INVESTIGATE INTER-COMPONENT CONFLICTS
• AUTOMATED RESOLUTION FOR DYNAMIC COMPONENTS
• COMPLEXITY ISSUES ASSOCIATED WITH MORE DEGREES OF
  FREEDOM

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• Thank You
• Questions?