Path Computation Policy Information Model (PCPIM) draft-bryskin-pce-pcpim-00.txt

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Path Computation Policy Information
Model(PCPIM)draft-bryskin-pce-pcpim-00.txt

• Igor Bryskin
  Lou Berger

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Draft Background

• The PCE architecture introduced the concept of
  PCE policy
• Policy-Enabled Path Computation Framework defined
  use of PCIM
• In draft-ietf-pce-policy-enabled-path-comp
• PCIM Policy Core Information Model (PCIM)
• This draft defines specifics on PCIM use
• Defines the Path Computation Policy Information
  Model (PCPIM) as sub-class of PCIM

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Draft Objectives

• PC Policy semantics
• PC Policy class definition for
• PC constraints
• PC capabilities
• PC variables and values
• PC actions
• Allow for future extendibility
• Work within PCE Policy Framework
• Leverage existing policy modeling tools
• PCIM/PCIMe

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Requirements for PC Policy Information Model

• Reuse of existing policy infrastructures (e.g.
  PCIM) management tools, access and communication
  protocols
• Support for various policies and policy
  configurations
• Support for policy-ignorant nodes
• Fault tolerance and recovery
• Scalability
• Security and denial of service considerations

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PCPIM Design Goals

• Model policies in a way close to how humans tend
  to think about policy
• Rule-based modeling
• Hierarchical organization of information
• Goal-oriented policy definition
• Policy domain scope rather than device scope
• Device-, vendor-independent modeling (using
  roles)
• Reusability of policy constructs
• Policies must enforceable
• Independency of PC methodology
• Easy extensibility

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Framework Example ConfigurationSingle PC Policy
Repository
PC Policy Management
PC Policy Repository (based on PCPIM)
Policy A
Policy B
PCC-PDP
PCE-PDP
e.g. COPS, COPS-PR
e.g. COPS, COPS-PR
PCC-PCE communication protocol
PCC-PEP
PCE-PEP
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PCIM Background Policy Rule Basics
PolicyRule
PolicyCondition (s)
PolicyAction (s)
PolicyConditionInPolicyRule association (s)
PolicyActionInPolicyRule association (s)
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Simple PCIM Policy Rule
CompoundPolicyCondition(s)
CompoundPolicyAction(s)
PolicyRule
SimplePolicyCondition(s)
SimplePolicyAction(s)
SimplePolicyConditionInPolicyRule
CompoundPolicyConditionInPolicyRule SimplePolicyA
ctionInPolicyRule CompoundPolicyActionInPolicyRule

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Modeling of PC Constraints
CompoundPolicyCondition(s)
CompoundPolicyAction(s)
PolicyRulegtPcPolicyPcReqRspComponent
(mandatory, relaxation priority)gt
PcPolicyPcReqRspComponent sub-class
SimplePolicyCondition(s)
SimplePolicyAction(s)
SimplePolicyConditionInPolicyRule
CompoundPolicyConditionInPolicyRule SimplePolicyA
ctionInPolicyRule CompoundPolicyActionInPolicyRule

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An Example of a PC Constraint

• PcPolicyBandwidthConstraint class models TE link
  bandwidth availability constraint
• Derived from the PcPolicyPcReqRspComponent class
• Properties
• Bandwidth
• Priority
• Directionality
• Can model the following logic
• if(PcPolicyServiceBandwidthVariable !0) then
  banwidthConstraint. bandwidth
• PcPolicyServiceBandwidth
  Variable bandwidthConstraint.directionality
  
• PcPolicyServiceBandwidthD
  irectionalityVariable bandwidthConstraint.priorit
  y
• PcPolicyServiceBandwidth
  PriorityVariable
• bandwidthConstraint.mandatory TRUE

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Details

• Theres a lot and were out of time
• A detailed version of this presentation is
  available

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Modeling Request Path Computation PC Action
PolicyActiongtPcPolicyAction(PCCID,
PCEID)gt PcPolicyActionRequestPathComputation
PcPolicyReqRspSet(s)
PcPolicyVariable1
PcPolicyReqRspComponent1
PcPolicyVariable2
PcPolicyReqRspComponent2
PcPolicyVariable3
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Modeling Send Path Computation Response PC
Action
PolicyActiongtPcPolicyAction(PCCID,
PCEID)gt PcPolicyActionSendPathComputationResponse
PcPolicyReqRspSet(s)
PcPolicyVariable1
PcPolicyReqRspComponent1
PcPolicyVariable2
PcPolicyReqRspComponent2
PcPolicyVariable3
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Next Steps

• Add formal class definitions
• Integrate comments
• Formalize contribution from others
• We welcome input and discussion on this draft --
  in private or on list!

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Thank You