Path Computation Policy Path Computation Policy Information ModelInformation Model

(PCPIM)(PCPIM)

draft-bryskin-pce-pcpim-00.txtdraft-bryskin-pce-pcpim-00.txt

Igor BryskinIgor Bryskin Lou Berger Lou Berger

IETF-67

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 Configuration:Single PC Policy Repository

PC Policy Management

PC Policy Repository(based on PCPIM)PCC-PDP PCE-PDP

PCC-PEP PCE-PEP

Policy A Policy B

e.g. COPS, COPS-PR e.g. COPS, COPS-PR

PCC-PCE communication protocol

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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

PolicyRule

SimplePolicyCondition(s) SimplePolicyAction(s)

SimplePolicyConditionInPolicyRule CompoundPolicyConditionInPolicyRuleSimplePolicyActionInPolicyRuleCompoundPolicyActionInPolicyRule

CompoundPolicyCondition(s) CompoundPolicyAction(s)

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Modeling of PC Constraints

PolicyRule=>PcPolicyPcReqRspComponent (mandatory, relaxation priority)=> PcPolicyPcReqRspComponent sub-class

SimplePolicyCondition(s) SimplePolicyAction(s)

CompoundPolicyCondition(s) CompoundPolicyAction(s)

SimplePolicyConditionInPolicyRule CompoundPolicyConditionInPolicyRuleSimplePolicyActionInPolicyRuleCompoundPolicyActionInPolicyRule

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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 = PcPolicyServiceBandwidthVariable;

bandwidthConstraint.directionality = PcPolicyServiceBandwidthDirectionalityVariable;

bandwidthConstraint.priority = PcPolicyServiceBandwidthPriorityVariable; bandwidthConstraint.mandatory = TRUE’

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Details

• There’s a lot and we’re out of time…

• A detailed version of this presentation is available

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Modeling “Request Path Computation” PC Action

PolicyAction=>PcPolicyAction(PCCID, PCEID)=>PcPolicyActionRequestPathComputation

PcPolicyReqRspSet(s)

PcPolicyReqRspComponent1

PcPolicyReqRspComponent2

PcPolicyVariable1

PcPolicyVariable2

PcPolicyVariable3

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Modeling “Send Path Computation Response” PC Action

PcPolicyReqRspSet(s)

PcPolicyReqRspComponent1

PcPolicyReqRspComponent2

PcPolicyVariable1

PcPolicyVariable2

PcPolicyVariable3

PolicyAction=>PcPolicyAction(PCCID, PCEID)=>PcPolicyActionSendPathComputationResponse

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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!

Thank YouThank You