rfc3060.txt

最新的RFC

Network Working Group                                           B. Moore
Request for Comments: 3060                                           IBM
Category: Standards Track                                    E. Ellesson
                                                         LongBoard, Inc.
                                                            J. Strassner
                                                           A. Westerinen
                                                           Cisco Systems
                                                           February 2001


        Policy Core Information Model -- Version 1 Specification

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

Abstract

   This document presents the object-oriented information model for
   representing policy information developed jointly in the IETF Policy
   Framework WG and as extensions to the Common Information Model (CIM)
   activity in the Distributed Management Task Force (DMTF).  This model
   defines two hierarchies of object classes:  structural classes
   representing policy information and control of policies, and
   association classes that indicate how instances of the structural
   classes are related to each other. Subsequent documents will define
   mappings of this information model to various concrete
   implementations, for example, to a directory that uses LDAPv3 as its
   access protocol.

Table of Contents

   1. Introduction.................................................... 4
   2. Modeling Policies............................................... 5
      2.1. Policy Scope............................................... 8
      2.2. Declarative versus Procedural Model........................ 8
   3. Overview of the Policy Core Information Model.................. 10
   4. Inheritance Hierarchies for the Policy Core Information Model.. 13
      4.1. Implications of CIM Inheritance........................... 15
   5. Details of the Model........................................... 15



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RFC 3060             Policy Core Information Model         February 2001


      5.1. Reusable versus Rule-Specific Conditions and Actions...... 15
      5.2. Roles..................................................... 17
      5.2.1. Roles and Role Combinations............................. 17
      5.2.2. The PolicyRoles Property................................ 21
      5.3. Local Time and UTC Time in PolicyTimePeriodConditions..... 21
      5.4. CIM Data Types............................................ 23
      5.5. Comparison between CIM and LDAP Class Specifications...... 24
   6. Class Definitions.............................................. 25
      6.1. The Abstract Class "Policy"............................... 25
      6.1.1. The Property "CommonName (CN)".......................... 26
      6.1.2. The Multi-valued Property "PolicyKeywords".............. 26
      6.1.3. The Property "Caption" (Inherited from ManagedElement).. 27
      6.1.4. The Property "Description" (Inherited from
             ManagedElement)......................................... 27
      6.2. The Class "PolicyGroup"................................... 27
      6.3. The Class "PolicyRule".................................... 29
      6.3.1. The Property "Enabled".................................. 31
      6.3.2. The Property "ConditionListType"........................ 31
      6.3.3. The Property "RuleUsage"................................ 31
      6.3.4. The Property "Priority"................................. 32
      6.3.5. The Property "Mandatory"................................ 32
      6.3.6. The Property "SequencedActions"......................... 33
      6.3.7. The Multi-valued Property "PolicyRoles"................. 33
      6.4. The Abstract Class "PolicyCondition"...................... 34
      6.5. The Class "PolicyTimePeriodCondition"..................... 36
      6.5.1. The Property "TimePeriod"............................... 38
      6.5.2. The Property "MonthOfYearMask".......................... 39
      6.5.3. The Property "DayOfMonthMask"........................... 39
      6.5.4. The Property "DayOfWeekMask"............................ 40
      6.5.5. The Property "TimeOfDayMask"............................ 41
      6.5.6. The Property "LocalOrUtcTime"........................... 42
      6.6. The Class "VendorPolicyCondition"......................... 42
      6.6.1. The Multi-valued Property "Constraint".................. 43
      6.6.2. The Property "ConstraintEncoding"....................... 43
      6.7. The Abstract Class "PolicyAction"......................... 44
      6.8. The Class "VendorPolicyAction"............................ 45
      6.8.1. The Multi-valued Property "ActionData".................. 45
      6.8.2. The Property "ActionEncoding"........................... 46
      6.9. The Class "PolicyRepository".............................. 46
   7. Association and Aggregation Definitions........................ 46
      7.1. Associations.............................................. 47
      7.2. Aggregations.............................................. 47
      7.3. The Abstract Aggregation "PolicyComponent................. 47
      7.4. The Aggregation "PolicyGroupInPolicyGroup"................ 47
      7.4.1. The Reference "GroupComponent".......................... 48
      7.4.2. The Reference "PartComponent"........................... 48
      7.5. The Aggregation "PolicyRuleInPolicyGroup"................. 48
      7.5.1. The Reference "GroupComponent".......................... 49



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      7.5.2. The Reference "PartComponent"........................... 49
      7.6. The Aggregation "PolicyConditionInPolicyRule"............. 49
      7.6.1. The Reference "GroupComponent".......................... 50
      7.6.2. The Reference "PartComponent"........................... 50
      7.6.3. The Property "GroupNumber".............................. 50
      7.6.4. The Property "ConditionNegated"......................... 51
      7.7. The Aggregation "PolicyRuleValidityPeriod"................ 51
      7.7.1. The Reference "GroupComponent".......................... 52
      7.7.2. The Reference "PartComponent"........................... 52
      7.8. The Aggregation "PolicyActionInPolicyRule"................ 52
      7.8.1. The Reference "GroupComponent".......................... 53
      7.8.2. The Reference "PartComponent"........................... 53
      7.8.3. The Property "ActionOrder".............................. 53
      7.9. The Abstract Association "PolicyInSystem"................. 54
      7.10. The Weak Association "PolicyGroupInSystem"............... 55
      7.10.1. The Reference "Antecedent"............................. 55
      7.10.2. The Reference "Dependent".............................. 55
      7.11. The Weak Association "PolicyRuleInSystem"................ 56
      7.11.1. The Reference "Antecedent"............................. 56
      7.11.2. The Reference "Dependent".............................. 56
      7.12. The Association "PolicyConditionInPolicyRepository"...... 56
      7.12.1. The Reference "Antecedent"............................. 57
      7.12.2. The Reference "Dependent".............................. 57
      7.13. The Association "PolicyActionInPolicyRepository"......... 57
      7.13.1. The Reference "Antecedent"............................. 58
      7.13.2. The Reference "Dependent".............................. 58
      7.14. The Aggregation "PolicyRepositoryInPolicyRepository"..... 58
      7.14.1. The Reference "GroupComponent"......................... 58
      7.14.2. The Reference "PartComponent".......................... 59
   8. Intellectual Property.......................................... 59
   9. Acknowledgements............................................... 59
   10. Security Considerations....................................... 60
   11. References.................................................... 62
   12. Authors' Addresses............................................ 64
   13. Appendix A:  Class Identification in a Native CIM
       Implementation................................................ 65
      13.1. Naming Instances of PolicyGroup and PolicyRule........... 65
      13.1.1. PolicyGroup's CIM Keys................................. 65
      13.1.2. PolicyRule's CIM Keys.................................. 66
      13.2. Naming Instances of PolicyCondition and Its Subclasses... 67
      13.2.1. PolicyCondition's CIM Keys............................. 69
      13.3. Naming Instances of PolicyAction and Its Subclasses...... 71
      13.4. Naming Instances of PolicyRepository..................... 72
      13.5. Role of the CreationClassName Property in Naming......... 73
      13.6. Object References........................................ 73
   14. Appendix B:  The Core Policy MOF.............................. 75
   15. Full Copyright Statement..................................... 100




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RFC 3060             Policy Core Information Model         February 2001


1. Introduction

   This document presents the object-oriented information model for
   representing policy information currently under joint development in
   the IETF Policy Framework WG and as extensions to the Common
   Information Model (CIM) activity in the Distributed Management Task
   Force (DMTF).  This model defines two hierarchies of object classes:
   structural classes representing policy information and control of
   policies, and association classes that indicate how instances of the
   structural classes are related to each other.  Subsequent documents
   will define mappings of this information model to various concrete
   implementations, for example, to a directory that uses LDAPv3 as its
   access protocol.  The components of the CIM schema are available via
   the following URL: http://www.dmtf.org/spec/cims.html [1].

   The policy classes and associations defined in this model are
   sufficiently generic to allow them to represent policies related to
   anything.  However, it is expected that their initial application in
   the IETF will be for representing policies related to QoS (DiffServ
   and IntServ) and to IPSec.  Policy models for application-specific
   areas such as these may extend the Core Model in several ways.  The
   preferred way is to use the PolicyGroup, PolicyRule, and
   PolicyTimePeriodCondition classes directly, as a foundation for
   representing and communicating policy information.  Then, specific
   subclasses derived from PolicyCondition and PolicyAction can capture
   application-specific definitions of conditions and actions of
   policies.

   Two subclasses, VendorPolicyCondition and VendorPolicyAction, are
   also included in this document, to provide a standard extension
   mechanism for vendor-specific extensions to the Policy Core
   Information Model.

   This document fits into the overall framework for representing,
   deploying, and managing policies being developed by the Policy
   Framework Working Group.  It traces its origins to work that was
   originally done for the Directory-enabled Networks (DEN)
   specification, reference [5].  Work on the DEN specification by the
   DEN Ad-Hoc Working Group itself has been completed.  Further work to
   standardize the models contained in it will be the responsibility of
   selected working groups of the CIM effort in the Distributed
   Management Task Force (DMTF).  DMTF standardization of the core
   policy model is the responsibility of the SLA Policy working group in
   the DMTF.







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   This document is organized in the following manner:

   o  Section 2 provides a general overview of policies and how they are
      modeled.

   o  Section 3 presents a high-level overview of the classes and
      associations comprising the Policy Core Information Model.

   o  The remainder of the document presents the detailed specifications
      for each of the classes and associations.

   o  Appendix A overviews naming for native CIM implementations.  Other
      mappings, such as LDAPv3, will have their own naming mechanisms.

   o  Appendix B reproduces the DMTF's Core Policy MOF specification.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119, reference
   [3].

2. Modeling Policies

   The classes comprising the Policy Core Information Model are intended
   to serve as an extensible class hierarchy (through specialization)
   for defining policy objects that enable application developers,
   network administrators, and policy administrators to represent
   policies of different types.

   One way to think of a policy-controlled network is to first model the
   network as a state machine and then use policy to control which state
   a policy-controlled device should be in or is allowed to be in at any
   given time.  Given this approach, policy is applied using a set of
   policy rules.  Each policy rule consists of a set of conditions and a
   set of actions.  Policy rules may be aggregated into policy groups.
   These groups may be nested, to represent a hierarchy of policies.

   The set of conditions associated with a policy rule specifies when
   the policy rule is applicable.  The set of conditions can be
   expressed as either an ORed set of ANDed sets of condition statements
   or an ANDed set of ORed sets of statements.  Individual condition
   statements can also be negated.  These combinations are termed,
   respectively, Disjunctive Normal Form (DNF) and Conjunctive Normal
   Form (CNF) for the conditions.

   If the set of conditions associated with a policy rule evaluates to
   TRUE, then a set of actions that either maintain the current state of
   the object or transition the object to a new state may be executed.



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RFC 3060             Policy Core Information Model         February 2001