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rfc:rfc3644

Network Working Group Y. Snir Request for Comments: 3644 Y. Ramberg Category: Standards Track Cisco Systems

                                                          J. Strassner
                                                            Intelliden
                                                              R. Cohen
                                                             Ntear LLC
                                                              B. Moore
                                                                   IBM
                                                         November 2003
         Policy Quality of Service (QoS) Information Model

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 (2003).  All Rights Reserved.

Abstract

 This document presents an object-oriented information model for
 representing Quality of Service (QoS) network management policies.
 This document is based on the IETF Policy Core Information Model and
 its extensions.  It defines an information model for QoS enforcement
 for differentiated and integrated services using policy.  It is
 important to note that this document defines an information model,
 which by definition is independent of any particular data storage
 mechanism and access protocol.

Snir, et al. Standards Track [Page 1] RFC 3644 Policy QoS Information Model November 2003

Table of Contents

 1.   Introduction. . . . . . . . . . . . . . . . . . . . . . . . .  5
      1.1.  The Process of QoS Policy Definition. . . . . . . . . .  5
      1.2.  Design Goals and Their Ramifications. . . . . . . . . .  8
            1.2.1.  Policy-Definition Oriented. . . . . . . . . . .  8
                    1.2.1.1.  Rule-based Modeling . . . . . . . . .  9
                    1.2.1.2.  Organize Information Hierarchically .  9
                    1.2.1.3.  Goal-Oriented Policy Definition . . . 10
            1.2.2. Policy Domain Model. . . . . . . . . . . . . . . 11
                    1.2.2.1.  Model QoS Policy in a Device- and
                              Vendor-Independent Manner . . . . . . 11
                    1.2.2.2.  Use Roles for Mapping Policy to
                              Network Devices . . . . . . . . . . . 11
                    1.2.2.3.  Reusability . . . . . . . . . . . . . 12
            1.2.3.  Enforceable Policy. . . . . . . . . . . . . . . 12
            1.2.4.  QPIM Covers Both Signaled And Provisioned QoS . 14
            1.2.5.  Interoperability for PDPs and Management
                    Applications. . . . . . . . . . . . . . . . . . 14
      1.3.  Modeling Abstract QoS Policies. . . . . . . . . . . . . 15
      1.4.  Rule Hierarchy. . . . . . . . . . . . . . . . . . . . . 17
            1.4.1.  Use of Hierarchy Within Bandwidth Allocation
                    Policies. . . . . . . . . . . . . . . . . . . . 17
            1.4.2.  Use of Rule Hierarchy to Describe Drop
                    Threshold Policies. . . . . . . . . . . . . . . 21
            1.4.3.  Restrictions of the Use of Hierarchy Within
                    QPIM. . . . . . . . . . . . . . . . . . . . . . 22
      1.5.  Intended Audiences. . . . . . . . . . . . . . . . . . . 23
 2.   Class Hierarchies . . . . . . . . . . . . . . . . . . . . . . 23
      2.1.  Inheritance Hierarchy . . . . . . . . . . . . . . . . . 23
      2.2.  Relationship Hierarchy. . . . . . . . . . . . . . . . . 26
 3.   QoS Actions . . . . . . . . . . . . . . . . . . . . . . . . . 26
      3.1.  Overview. . . . . . . . . . . . . . . . . . . . . . . . 26
      3.2.  RSVP Policy Actions . . . . . . . . . . . . . . . . . . 27
            3.2.1.  Example: Controlling COPS Stateless Decision. . 28
            3.2.2.  Example: Controlling the COPS Replace Decision. 29
      3.3.  Provisioning Policy Actions . . . . . . . . . . . . . . 29
            3.3.1.  Admission Actions: Controlling Policers and
                    Shapers . . . . . . . . . . . . . . . . . . . . 29
            3.3.2.  Controlling Markers . . . . . . . . . . . . . . 32
            3.3.3.  Controlling Edge Policies - Examples. . . . . . 33
      3.4.  Per-Hop Behavior Actions. . . . . . . . . . . . . . . . 34
            3.4.1.  Controlling Bandwidth and Delay . . . . . . . . 35
            3.4.2.  Congestion Control Actions. . . . . . . . . . . 35
            3.4.3.  Using Hierarchical Policies: Examples for PHB
                    Actions . . . . . . . . . . . . . . . . . . . . 36
 4.   Traffic Profiles. . . . . . . . . . . . . . . . . . . . . . . 38
      4.1.  Provisioning Traffic Profiles . . . . . . . . . . . . . 38

Snir, et al. Standards Track [Page 2] RFC 3644 Policy QoS Information Model November 2003

      4.2.  RSVP Traffic Profiles . . . . . . . . . . . . . . . . . 39
 5.   Pre-Defined QoS-Related Variables . . . . . . . . . . . . . . 40
 6.   QoS Related Values. . . . . . . . . . . . . . . . . . . . . . 42
 7.   Class Definitions: Association Hierarchy. . . . . . . . . . . 44
      7.1.  The Association "QoSPolicyTrfcProfInAdmissionAction". . 44
            7.1.1.  The Reference "Antecedent". . . . . . . . . . . 44
            7.1.2.  The Reference "Dependent" . . . . . . . . . . . 44
      7.2.  The Association "PolicyConformAction" . . . . . . . . . 44
            7.2.1.  The Reference "Antecedent". . . . . . . . . . . 45
            7.2.2.  The Reference "Dependent" . . . . . . . . . . . 45
      7.3.  The Association "QoSPolicyExceedAction" . . . . . . . . 45
            7.3.1.  The Reference "Antecedent". . . . . . . . . . . 46
            7.3.2.  The Reference "Dependent" . . . . . . . . . . . 46
      7.4.  The Association "PolicyViolateAction" . . . . . . . . . 46
            7.4.1.  The Reference "Antecedent". . . . . . . . . . . 46
            7.4.2.  The Reference "Dependent" . . . . . . . . . . . 47
      7.5   The Aggregation
            "QoSPolicyRSVPVariableInRSVPSimplePolicyAction" . . . . 47
            7.5.1.  The Reference "GroupComponent". . . . . . . . . 47
            7.5.2.  The Reference "PartComponent" . . . . . . . . . 47
 8.   Class Definitions: Inheritance Hierarchy. . . . . . . . . . . 48
      8.1.  The Class QoSPolicyDiscardAction. . . . . . . . . . . . 48
      8.2.  The Class QoSPolicyAdmissionAction. . . . . . . . . . . 48
            8.2.1.  The Property qpAdmissionScope . . . . . . . . . 48
      8.3.  The Class QoSPolicyPoliceAction . . . . . . . . . . . . 49
      8.4.  The Class QoSPolicyShapeAction. . . . . . . . . . . . . 49
      8.5.  The Class QoSPolicyRSVPAdmissionAction. . . . . . . . . 50
            8.5.1.  The Property qpRSVPWarnOnly . . . . . . . . . . 50
            8.5.2.  The Property qpRSVPMaxSessions. . . . . . . . . 51
      8.6.  The Class QoSPolicyPHBAction. . . . . . . . . . . . . . 51
            8.6.1.  The Property qpMaxPacketSize. . . . . . . . . . 51
      8.7.  The Class QoSPolicyBandwidthAction. . . . . . . . . . . 52
            8.7.1.  The Property qpForwardingPriority . . . . . . . 52
            8.7.2.  The Property qpBandwidthUnits . . . . . . . . . 52
            8.7.3.  The Property qpMinBandwidth . . . . . . . . . . 53
            8.7.4.  The Property qpMaxBandwidth . . . . . . . . . . 53
            8.7.5.  The Property qpMaxDelay . . . . . . . . . . . . 53
            8.7.6.  The Property qpMaxJitter. . . . . . . . . . . . 53
            8.7.7.  The Property qpFairness . . . . . . . . . . . . 54
      8.8.  The Class QoSPolicyCongestionControlAction. . . . . . . 54
            8.8.1.  The Property qpQueueSizeUnits . . . . . . . . . 54
            8.8.2.  The Property qpQueueSize. . . . . . . . . . . . 55
            8.8.3.  The Property qpDropMethod . . . . . . . . . . . 55
            8.8.4.  The Property qpDropThresholdUnits . . . . . . . 55
            8.8.5.  The Property qpDropMinThresholdValue. . . . . . 55
            8.8.6.  The Property qpDropMaxThresholdValue. . . . . . 56
      8.9.  The Class QoSPolicyTrfcProf . . . . . . . . . . . . . . 56
      8.10. The Class QoSPolicyTokenBucketTrfcProf. . . . . . . . . 57

Snir, et al. Standards Track [Page 3] RFC 3644 Policy QoS Information Model November 2003

            8.10.1. The Property qpTBRate . . . . . . . . . . . . . 57
            8.10.2. The Property qpTBNormalBurst. . . . . . . . . . 57
            8.10.3. The Property qpTBExcessBurst. . . . . . . . . . 57
      8.11. The Class QoSPolicyIntServTrfcProf. . . . . . . . . . . 57
            8.11.1. The Property qpISTokenRate. . . . . . . . . . . 58
            8.11.2. The Property qpISPeakRate . . . . . . . . . . . 58
            8.11.3. The Property qpISBucketSize . . . . . . . . . . 58
            8.11.4. The Property qpISResvRate . . . . . . . . . . . 58
            8.11.5. The Property qpISResvSlack. . . . . . . . . . . 59
            8.11.6. The Property qpISMinPolicedUnit . . . . . . . . 59
            8.11.7. The Property qpISMaxPktSize . . . . . . . . . . 59
      8.12. The Class QoSPolicyAttributeValue . . . . . . . . . . . 59
            8.12.1. The Property qpAttributeName. . . . . . . . . . 60
            8.12.2. The Property qpAttributeValueList . . . . . . . 60
      8.13. The Class QoSPolicyRSVPVariable . . . . . . . . . . . . 60
      8.14. The Class QoSPolicyRSVPSourceIPv4Variable . . . . . . . 61
      8.15. The Class QoSPolicyRSVPDestinationIPv4Variable. . . . . 61
      8.16. The Class QoSPolicyRSVPSourceIPv6Variable . . . . . . . 62
      8.17. The Class QoSPolicyRSVPDestinationIPv6Variable. . . . . 62
      8.18. The Class QoSPolicyRSVPSourcePortVariable . . . . . . . 62
      8.19. The Class QoSPolicyRSVPDestinationPortVariable. . . . . 63
      8.20. The Class QoSPolicyRSVPIPProtocolVariable . . . . . . . 63
      8.21. The Class QoSPolicyRSVPIPVersionVariable. . . . . . . . 63
      8.22. The Class QoSPolicyRSVPDCLASSVariable . . . . . . . . . 64
      8.23. The Class QoSPolicyRSVPStyleVariable. . . . . . . . . . 64
      8.24. The Class QoSPolicyRSVPIntServVariable. . . . . . . . . 65
      8.25. The Class QoSPolicyRSVPMessageTypeVariable. . . . . . . 65
      8.26. The Class QoSPolicyRSVPPreemptionPriorityVariable . . . 65
      8.27. The Class QoSPolicyRSVPPreemptionDefPriorityVariable. . 66
      8.28. The Class QoSPolicyRSVPUserVariable . . . . . . . . . . 66
      8.29. The Class QoSPolicyRSVPApplicationVariable. . . . . . . 66
      8.30. The Class QoSPolicyRSVPAuthMethodVariable . . . . . . . 67
      8.31. The Class QosPolicyDNValue. . . . . . . . . . . . . . . 67
            8.31.1. The Property qpDNList . . . . . . . . . . . . . 68
      8.32. The Class QoSPolicyRSVPSimpleAction . . . . . . . . . . 68
            8.32.1. The Property qpRSVPActionType . . . . . . . . . 68
 9.   Intellectual Property Rights Statement. . . . . . . . . . . . 69
 10.  Acknowledgements. . . . . . . . . . . . . . . . . . . . . . . 69
 11.  Security Considerations . . . . . . . . . . . . . . . . . . . 69
 12.  References. . . . . . . . . . . . . . . . . . . . . . . . . . 70
      12.1.  Normative References . . . . . . . . . . . . . . . . . 70
      12.2.  Informative References . . . . . . . . . . . . . . . . 70
 13.  Authors' Addresses. . . . . . . . . . . . . . . . . . . . . . 72
 14.  Full Copyright Statement. . . . . . . . . . . . . . . . . . . 73

Snir, et al. Standards Track [Page 4] RFC 3644 Policy QoS Information Model November 2003

1. Introduction

 The QoS Policy Information Model (QPIM) establishes a standard
 framework and constructs for specifying and representing policies
 that administer, manage, and control access to network QoS resources.
 Such policies will be referred to as "QoS policies" in this document.
 The framework consists of a set of classes and relationships that are
 organized in an object-oriented information model.  It is agnostic of
 any specific Policy Decision Point (PDP) or Policy Enforcement Point
 (PEP) (see [TERMS] for definitions) implementation, and independent
 of any particular QoS implementation mechanism.
 QPIM is designed to represent QoS policy information for large-scale
 policy domains (the term "policy domain" is defined in [TERMS]).  A
 primary goal of this information model is to assist human
 administrators in their definition of policies to control QoS
 resources (as opposed to individual network element configuration).
 The process of creating QPIM data instances is fed by business rules,
 network topology and QoS methodology (e.g., Differentiated Services).
 This document is based on the IETF Policy Core Information Model and
 its extensions as specified by [PCIM] and [PCIMe].  QPIM builds upon
 these two documents to define an information model for QoS
 enforcement for differentiated and integrated services ([DIFFSERV]
 and [INTSERV], respectively) using policy.  It is important to note
 that this document defines an information model, which by definition
 is independent of any particular data storage mechanism and access
 protocol.  This enables various data models (e.g., directory
 schemata, relational database schemata, and SNMP MIBs) to be designed
 and implemented according to a single uniform model.
 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 BCP 14, RFC 2119
 [KEYWORDS].

1.1. The Process of QoS Policy Definition

 This section describes the process of using QPIM for the definition
 QoS policy for a policy domain.  Figure 1 illustrates information
 flow and not the actual procedure, which has several loops and
 feedback not depicted.

Snir, et al. Standards Track [Page 5] RFC 3644 Policy QoS Information Model November 2003

  1. ——— ———- ———–

| Business | | Topology | | QoS |

 | Policy   |      |          |     |Methodology|
  ----------        ----------       -----------
      |                  |               |
      |                  |               |
      ------------------------------------
                         |
                         V
                  ---------------
                 |  QPIM/PCIM(e) |
                 |   modeling    |
                  ---------------
                         |
                         |            --------------
                         |<----------| Device info, |
                         |           | capabilities |
                         |            --------------
                         V
                  (---------------)
                  (    device     )---)
                  ( configuration )   )---)
                  (---------------)   )   )
                       (--------------)   )
                            (-------------)
             Figure 1: The QoS definition information flow
 The process of QoS policy definition is dependent on three types of
 information: the topology of the network devices under management,
 the particular type of QoS methodology used (e.g., DiffServ) and the
 business rules and requirements for specifying service(s) [TERMS]
 delivered by the network.  Both topology and business rules are
 outside the scope of QPIM.  However, important facets of both must be
 known and understood for correctly specifying the QoS policy.
 Typically, the process of QoS policy definition relies on a
 methodology based on one or more QoS methodologies.  For example, the
 DiffServ methodology may be employed in the QoS policy definition
 process.
 The topology of the network consists of an inventory of the network
 elements that make up the network and the set of paths that traffic
 may take through the network.  For example, a network administrator
 may decide to use the DiffServ architectural model [DIFFSERV] and
 classify network devices using the roles "boundary" and "core" (see
 [TERMS] for a definition of role, and [PCIM] for an explanation of

Snir, et al. Standards Track [Page 6] RFC 3644 Policy QoS Information Model November 2003

 how they are used in the policy framework).  While this is not a
 complete topological view of the network, many times it may suffice
 for the purpose of QoS policy definition.
 Business rules are informal sets of requirements for specifying the
 behavior of various types of traffic that may traverse the network.
 For example, the administrator may be instructed to implement policy
 such that VoIP traffic manifests behavior that is similar to legacy
 voice traffic over telephone networks.  Note that this business rule
 (indirectly) prescribes specific behavior for this traffic type
 (VoIP), for example in terms of minimal delay, jitter and loss.
 Other traffic types, such as WEB buying transactions, system backup
 traffic, video streaming, etc., will express their traffic
 conditioning requirements in different terms.  Again, this
 information is required not by QPIM itself, but by the overall policy
 management system that uses QPIM.  QPIM is used to help map the
 business rules into a form that defines the requirements for
 conditioning different types of traffic in the network.
 The topology, QoS methodology, and business rules are necessary
 prerequisites for defining traffic conditioning.  QPIM enables a set
 of tools for specifying traffic conditioning policy in a standard
 manner.  Using a standard QoS policy information model such as QPIM
 is needed also because different devices can have markedly different
 capabilities.  Even the same model of equipment can have different
 functionality if the network operating system and software running in
 those devices is different.  Therefore, a means is required to
 specify functionality in a standard way that is independent of the
 capabilities of different vendors' devices.  This is the role of
 QPIM.
 In a typical scenario, the administrator would first determine the
 role(s) that each interface of each network element plays in the
 overall network topology.  These roles define the functions supplied
 by a given network element independent of vendor and device type.
 The [PCIM] and [PCIMe] documents define the concept of a role.  Roles
 can be used to identify what parts of the network need which type of
 traffic conditioning.  For example, network interface cards that are
 categorized as "core" interfaces can be assigned the role name
 "core-interface".  This enables the administrator to design policies
 to configure all interfaces having the role "core-interface"
 independent of the actual physical devices themselves.  QPIM uses
 roles to help the administrator map a given set of devices or
 interfaces to a given set of policy constructs.

Snir, et al. Standards Track [Page 7] RFC 3644 Policy QoS Information Model November 2003

 The policy constructs define the functionality required to perform
 the desired traffic conditioning for particular traffic type(s).  The
 functions themselves depend on the particular type of networking
 technologies chosen.  For example, the DiffServ methodology
 encourages us to aggregate similar types of traffic by assigning to
 each traffic class a particular per-hop forwarding behavior on each
 node.  RSVP enables bandwidth to be reserved.  These two
 methodologies can be used separately or in conjunction, as defined by
 the appropriate business policy.  QPIM provides specific classes to
 enable DiffServ and RSVP conditioning to be modeled.
 The QPIM class definitions are used to create instances of various
 policy constructs such as QoS actions and conditions that may be
 hierarchically organized in rules and groups (PolicyGroup and
 PolicyRule as defined in [PCIM] and [PCIMe]).  Examples of policy
 actions are rate limiting, jitter control and bandwidth allocation.
 Policy conditions are constructs that can select traffic according to
 a complex Boolean expression.
 A hierarchical organization was chosen for two reasons.  First, it
 best reflects the way humans tend to think about complex policy.
 Second, it enables policy to be easily mapped onto administrative
 organizations, as the hierarchical organization of policy mirrors
 most administrative organizations.  It is important to note that the
 policy definition process described here is done independent of any
 specific device capabilities and configuration options.  The policy
 definition is completely independent from the details of the
 implementation and the configuration interface of individual network
 elements, as well as of the mechanisms that a network element can use
 to condition traffic.

1.2. Design Goals and Their Ramifications

 This section explains the QPIM design goals and how these goals are
 addressed in this document.  This section also describes the
 ramifications of the design goals and the design decisions made in
 developing QPIM.

1.2.1. Policy-Definition Oriented

 The primary design goal of QPIM is to model policies controlling QoS
 behavior in a way that as closely as possible reflects the way humans
 tend to think about policy.  Therefore, QPIM is designed to address
 the needs of policy definition and management, and not device/network
 configuration.

Snir, et al. Standards Track [Page 8] RFC 3644 Policy QoS Information Model November 2003

 There are several ramifications of this design goal.  First, QPIM
 uses rules to define policies, based on [PCIM] and [PCIMe].  Second,
 QPIM uses hierarchical organizations of policies and policy
 information extensively.  Third, QPIM does not force the policy
 writer to specify all implementation details; rather, it assumes that
 configuration agents (PDPs) interpret the policies and match them to
 suit the needs of device-specific configurations.

1.2.1.1. Rule-based Modeling

 Policy is best described using rule-based modeling as explained and
 described in [PCIM] and [PCIMe].  A QoS policy rule is structured as
 a condition clause and an action clause.  The semantics are simple:
 if the condition clause evaluates to TRUE, then a set of QoS actions
 (specified in the action clause) can be executed.  For example, the
 rule:
    "WEB traffic should receive at least 50% of the available
    bandwidth resources or more, when more is available"
 can be formalized as:
    "<If protocol == HTTP> then <minimum BW = 50%>"
 where the first angle bracketed clause is a traffic condition and the
 second angle bracketed clause is a QoS action.
 This approach differs from data path modeling that describes the
 mechanisms that operates on the packet flows to achieve the desired
 effect.
 Note that the approach taken in QPIM specifically did NOT subclass
 the PolicyRule class.  Rather, it uses the SimplePolicyCondition,
 CompoundPolicyCondition, SimplePolicyAction, and CompoundPolicyAction
 classes defined in [PCIMe], as well as defining subclasses of the
 following classes: Policy, PolicyAction, SimplePolicyAction,
 PolicyImplicitVariable, and PolicyValue.  Subclassing the PolicyRule
 class would have made it more difficult to combine actions and
 conditions defined within different functional domains [PCIMe] within
 the same rules.

1.2.1.2. Organize Information Hierarchically

 The organization of the information represented by QPIM is designed
 to be hierarchical.  To do this, QPIM utilizes the PolicySetComponent
 aggregation [PCIMe] to provide an arbitrarily nested organization of
 policy information.  A policy group functions as a container of

Snir, et al. Standards Track [Page 9] RFC 3644 Policy QoS Information Model November 2003

 policy rules and/or policy groups.  A policy rule can also contain
 policy rules and/or groups, enabling a rule/sub-rule relationship to
 be realized.
 The hierarchical design decision is based on the realization that it
 is natural for humans to organize policy rules in groups.  Breaking
 down a complex policy into a set of simple rules is a process that
 follows the way people tend to think and analyze systems.  The
 complexity of the abstract, business-oriented policy is simplified
 and made into a hierarchy of simple rules and grouping of simple
 rules.
 The hierarchical information organization helps to simplify the
 definition and readability of data instances based on QPIM.
 Hierarchies can also serve to carry additional semantics for QoS
 actions in a given context.  An example, detailed in section 2.3,
 demonstrates how hierarchical bandwidth allocation policies can be
 specified in an intuitive form, without the need to specify complex
 scheduler structures.

1.2.1.3. Goal-Oriented Policy Definition

 QPIM facilitates goal-oriented QoS policy definition.  This means
 that the process of defining QoS policy is focused on the desired
 effect of policies, as opposed to the means of implementing the
 policy on network elements.
 QPIM is intended to define a minimal specification of desired network
 behavior.  It is the role of device-specific configuration agents to
 interpret policy expressed in a standard way and fill in the
 necessary configuration details that are required for their
 particular application.  The benefit of using QPIM is that it
 provides a common lingua franca that each of the device- and/or
 vendor-specific configuration agents can use.  This helps ensure a
 common interpretation of the general policy as well as aid the
 administrator in specifying a common policy to be implemented across
 different devices.  This is analogous to the fundamental object-
 oriented paradigm of separating specification from implementation.
 Using QPIM, traffic conditioning can be specified in a general manner
 that can help different implementations satisfy a common goal.
 For example, a valid policy may include only a single rule that
 specifies that bandwidth should be reserved for a given set of
 traffic flows.  The rule does not need to include any of the various
 other details that may be needed for implementing a scheduler that
 supports this bandwidth allocation (e.g., the queue length required).
 It is assumed that a PDP or the PEPs would fill in these details
 using (for example) their default queue length settings.  The policy

Snir, et al. Standards Track [Page 10] RFC 3644 Policy QoS Information Model November 2003

 writer need only specify the main goal of the policy, making sure
 that the preferred application receives enough bandwidth to operate
 adequately.

1.2.2. Policy Domain Model

 An important design goal of QPIM is to provide a means for defining
 policies that span numerous devices.  This goal differentiates QPIM
 from device-level information models, which are designed for modeling
 policy that controls a single device, its mechanisms and
 capabilities.
 This design goal has several ramifications.  First, roles [PCIM] are
 used to define policies across multiple devices.  Second, the use of
 abstract policies frees the policy definition process from having to
 deal with individual device peculiarities, and leaves interpretation
 and configuration to be modeled by PDPs or other configuration
 agents. Third, QPIM allows extensive reuse of all policy building
 blocks in multiple rules used within different devices.

1.2.2.1. Model QoS Policy in a Device- and Vendor-Independent Manner

 QPIM models QoS policy in a way designed to be independent of any
 particular device or vendor.  This enables networks made up of
 different devices that have different capabilities to be managed and
 controlled using a single standard set of policies.  Using such a
 single set of policies is important because otherwise, the policy
 will itself reflect the differences between different device
 implementations.

1.2.2.2. Use Roles for Mapping Policy to Network Devices

 The use of roles enables a policy definition to be targeted to the
 network function of a network element, rather than to the element's
 type and capabilities.  The use of roles for mapping policy to
 network elements provides an efficient and simple method for compact
 and abstract policy definition.  A given abstract policy may be
 mapped to a group of network elements without the need to specify
 configuration for each of those elements based on the capabilities of
 any one individual element.
 The policy definition is designed to allow aggregating multiple
 devices within the same role, if desired.  For example, if two core
 network interfaces operate at different rates, one does not have to
 define two separate policy rules to express the very same abstract
 policy (e.g., allocating 30% of the interface bandwidth to a given

Snir, et al. Standards Track [Page 11] RFC 3644 Policy QoS Information Model November 2003

 preferred set of flows).  The use of hierarchical context and
 relative QoS actions in QPIM addresses this and other related
 problems.

1.2.2.3. Reusability

 Reusable objects, as defined by [PCIM] and [PCIMe], are the means for
 sharing policy building blocks, thus allowing central management of
 global concepts.  QPIM provides the ability to reuse all policy
 building blocks: variables and values, conditions and actions,
 traffic profiles, and policy groups and policy rules.  This provides
 the required flexibility to manage large sets of policy rules over
 large policy domains.
 For example, the following rule makes use of centrally defined
 objects being reused (referenced):
    If <DestinationAddress == FinanceSubNet> then <DSCP =
    MissionCritical>
 In this rule, the condition refers to an object named FinanceSubNet,
 which is a value (or possibly a set of values) defined and maintained
 in a reusable objects container.  The QoS action makes use of a value
 named MissionCritical, which is also a reusable object.  The
 advantage of specifying a policy in this way is its inherent
 flexibility.  Given the above policy, whenever business needs require
 a change in the subnet definition for the organization, all that's
 required is to change the reusable value FinanceSubNet centrally.
 All referencing rules are immediately affected, without the need to
 modify them individually. Without this capability, the repository
 that is used to store the rules would have to be searched for all
 rules that refer to the finance subnet, and then each matching rule's
 condition would have to be individually updated.  This is not only
 much less efficient, but also is more prone to error.
 For a complete description of reusable objects, refer to [PCIM] and
 [PCIMe].

1.2.3. Enforceable Policy

 Policy defined by QPIM should be enforceable.  This means that a PDP
 can use QPIM's policy definition in order to make the necessary
 decisions and enforce the required policy rules.  For example, RSVP
 admission decisions should be made based on the policy definitions
 specified by QPIM.  A PDP should be able to map QPIM policy
 definitions into PEP configurations, using either standard or
 proprietary protocols.

Snir, et al. Standards Track [Page 12] RFC 3644 Policy QoS Information Model November 2003

 QPIM is designed to be agnostic of any particular, vendor-dependent
 technology.  However, QPIM's constructs SHOULD always be interpreted
 so that policy-compliant behavior can be enforced on the network
 under management.  Therefore, there are three fundamental
 requirements that QPIM must satisfy:
 1. Policy specified by QPIM must be able to be mapped to actual
    network elements.
 2. Policy specified by QPIM must be able to control QoS network
    functions without making reference to a specific type of device or
    vendor.
 3. Policy specified by QPIM must be able to be translated into
    network element configuration.
 QPIM satisfies requirements #1 and #2 above by using the concept of
 roles (specifically, the PolicyRoles property, defined in PCIM).  By
 matching roles assigned to policy groups and to network elements, a
 PDP (or other enforcement agent) can determine what policy should be
 applied to a given device or devices.
 The use of roles in mapping policy to network elements supports model
 scalability.  QPIM policy can be mapped to large-scale policy domains
 by assigning a single role to a group of network elements.  This can
 be done even when the policy domain contains heterogeneous devices.
 So, a small set of policies can be deployed to large networks without
 having to re-specify the policy for each device separately.  This
 QPIM property is important for QoS policy management applications
 that strive to ease the task of policy definition for large policy
 domains.
 Requirement #2 is also satisfied by making QPIM domain-oriented (see
 [TERMS] for a definition of "domain").  In other words, the target of
 the policy is a domain, as opposed to a specific device or interface.
 Requirement #3 is satisfied by modeling QoS conditions and actions
 that are commonly configured on various devices.  However, QPIM is
 extensible to allow modeling of actions that are not included in
 QPIM.
 It is important to note that different PEPs will have different
 capabilities and functions, which necessitate different individual
 configurations even if the different PEPs are controlled by the same
 policy.

Snir, et al. Standards Track [Page 13] RFC 3644 Policy QoS Information Model November 2003

1.2.4. QPIM Covers Both Signaled And Provisioned QoS

 The two predominant standards-based QoS methodologies developed so
 far are Differentiated Services (DiffServ) and Integrated Services
 (IntServ).  The DiffServ provides a way to enforce policies that
 apply to a large number of devices in a scalable manner.  QPIM
 provides actions and conditions that control the classification,
 policing and shaping done within the differentiated service domain
 boundaries, as well as actions that control the per-hop behavior
 within the core of the DiffServ network.  QPIM does not mandate the
 use of DiffServ as a policy methodology.
 Integrated services, together with its signaling protocol (RSVP),
 provides a way for end nodes (and edge nodes) to request QoS from the
 network.  QPIM provides actions that control the reservation of such
 requests within the network.
 As both methodologies continue to evolve, QPIM does not attempt to
 provide full coverage of all possible scenarios.  Instead, QPIM aims
 to provide policy control modeling for all major scenarios.  QPIM is
 designed to be extensible to allow for incorporation of control over
 newly developed QoS mechanisms.

1.2.5. Interoperability for PDPs and Management Applications

 Another design goal of QPIM is to facilitate interoperability among
 policy systems such as PDPs and policy management applications.  QPIM
 accomplishes this interoperability goal by standardizing the
 representation of policy.  Producers and consumers of QoS policy need
 only rely on QPIM-based schemata (and resulting data models) to
 ensure mutual understanding and agreement on the semantics of QoS
 policy.
 For example, suppose that a QoS policy management application, built
 by vendor A writes its policies based on the LDAP schema that maps
 from QPIM to a directory implementation using LDAP.  Now assume that
 a separately built PDP from vendor B also relies on this same LDAP
 schema derived from QPIM.  Even though these are two vendors with two
 different PDPs, each may read the schema of the other and
 "understand" it.  This is because both the management application and
 the PDP were architected to comply with the QPIM specification.  The
 same is true with two policy management applications.  For example,
 vendor B's policy application may run a validation tool that computes
 whether there are conflicts within rules specified by the other
 vendor's policy management application.

Snir, et al. Standards Track [Page 14] RFC 3644 Policy QoS Information Model November 2003

 Interoperability of QPIM producers/consumers is by definition at a
 high level, and does not guarantee that the same policy will result
 in the same PEP configuration.  First, different PEPs will have
 different capabilities and functions, which necessitate different
 individual configurations even if the different PEPs are controlled
 by the same policy.  Second, different PDPs will also have different
 capabilities and functions, and may choose to translate the high-
 level QPIM policy differently depending on the functionality of the
 PDP, as well as on the capabilities of the PEPs that are being
 controlled by the PDP.  However, the different configurations should
 still result in the same network behavior as that specified by the
 policy rules.

1.3. Modeling Abstract QoS Policies

 This section provides a discussion of QoS policy abstraction and the
 way QPIM addresses this issue.
 As described above, the main goal of the QPIM is to create an
 information model that can be used to help bridge part of the
 conceptual gap between a human policy maker and a network element
 that is configured to enforce the policy.  Clearly this wide gap
 implies several translation levels, from the abstract to the
 concrete.  At the abstract end are the business QoS policy rules.
 Once the business rules are known, a network administrator must
 interpret them as network QoS policy and represent this QoS policy by
 using QPIM constructs.  QPIM facilitates a formal representation of
 QoS rules, thus providing the first concretization level: formally
 representing humanly expressed QoS policy.
 When a human business executive defines network policy, it is usually
 done using informal business terms and language.  For example, a
 human may utter a policy statement that reads:
    "human resources applications should have better QoS than simple
    web applications"
 This might be translated to a slightly more sophisticated form, such
 as:
    "traffic generated by our human resources applications should have
    a higher probability of communicating with its destinations than
    traffic generated by people browsing the WEB using non-mission-
    critical applications"
 While this statement clearly defines QoS policy at the business
 level, it isn't specific enough to be enforceable by network
 elements. Translation to "network terms and language" is required.

Snir, et al. Standards Track [Page 15] RFC 3644 Policy QoS Information Model November 2003

 On the other end of the scale, a network element functioning as a
 PEP, such as a router, can be configured with specific commands that
 determine the operational parameters of its inner working QoS
 mechanisms.  For example, the (imaginary) command "output-queue-depth
 = 100" may be an instruction to a network interface card of a router
 to allow up to 100 packets to be stored before subsequent packets are
 discarded (not forwarded).  On a different device within the same
 network, the same instruction may take another form, because a
 different vendor built that device or it has a different set of
 functions, and hence implementation, even though it is from the same
 vendor.  In addition, a particular PEP may not have the ability to
 create queues that are longer than, say, 50 packets, which may result
 in a different instruction implementing the same QoS policy.
 The first example illustrates 'abstract policy', while the second
 illustrates 'concrete configuration'.  Furthermore, the first example
 illustrates end-to-end policy, which covers the conditioning of
 application traffic throughout the network.  The second example
 illustrates configuration for a particular PEP or a set thereof.
 While an end-to-end policy statement can only be enforced by
 configuration of PEPs in various parts of the network, the
 information model of policy and that of the mechanisms that a PEP
 uses to implement that policy are vastly different.
 The translation process from abstract business policy to concrete PEP
 configuration is roughly expressed as follows:
 1. Informal business QoS policy is expressed by a human policy maker
    (e.g., "All executives' WEB requests should be prioritized ahead
    of other employees' WEB requests")
 2. A network administrator analyzes the policy domain's topology and
    determines the roles of particular device interfaces.  A role may
    be assigned to a large group of elements, which will result in
    mapping a particular policy to a large group of device interfaces.
 3. The network administrator models the informal policy using QPIM
    constructs, thus creating a formal representation of the abstract
    policy.  For example, "If a packet's protocol is HTTP and its
    destination is in  the 'EXECUTIVES' user group, then assign IPP 7
    to the packet header".
 4. The network administrator assigns roles to the policy groups
    created in the previous step matching the network elements' roles
    assigned in step #2 above.

Snir, et al. Standards Track [Page 16] RFC 3644 Policy QoS Information Model November 2003

 5. A PDP translates the abstract policy constructs created in step #3
    into device-specific configuration commands for all devices
    effected by the new policy (i.e., devices that have interfaces
    that are assigned a role matching the new policy constructs'
    roles).  In this process, the PDP consults the particular devices'
    capabilities to determine the appropriate configuration commands
    implementing the policy.
 6. For each PEP in the network, the PDP (or an agent of the PDP)
    issues the appropriate device-specific instructions necessary to
    enforce the policy.
 QPIM, PCIM and PCIMe are used in step #3 above.

1.4. Rule Hierarchy

 Policy is described by a set of policy rules that may be grouped into
 subsets [PCIMe].  Policy rules and policy groups can be nested within
 other policy rules, providing a hierarchical policy definition.
 Nested rules are also called sub-rules, and we use both terms in this
 document interchangeably.  The aggregation PolicySetComponent
 (defined in [PCIMe] is used to represent the nesting of a policy rule
 or group in another policy rule.
 The hierarchical policy rule definition enhances policy readability
 and reusability.  Within the QoS policy information model, hierarchy
 is used to model context or scope for the sub-rule actions.  Within
 QPIM, bandwidth allocation policy actions and drop threshold actions
 use this hierarchal context.  First we provide a detailed example of
 the use of hierarchy in bandwidth allocation policies.  The
 differences between flat and hierarchical policy representation are
 discussed.  The use of hierarchy in drop threshold policies is
 described in a following subsection.  Last but not least, the
 restrictions on the use of rule hierarchies within QPIM are
 described.

1.4.1. Use of Hierarchy Within Bandwidth Allocation Policies

 Consider the following example where the informal policy reads:
    On any interface on which these rules apply, guarantee at least
    30% of the interface bandwidth to UDP flows, and at least 40% of
    the interface bandwidth to TCP flows.
 The QoS Policy information model follows the Policy Core information
 model by using roles as a way to specify the set of interfaces on
 which this policy applies.  The policy does not assume that all
 interfaces are run at the same speed, or have any other property in

Snir, et al. Standards Track [Page 17] RFC 3644 Policy QoS Information Model November 2003

 common apart from being able to forward packets.  Bandwidth is
 allocated between UDP and TCP flows using percentages of the
 available interface bandwidth.  Assume that we have an available
 interface bandwidth of 1 Mbits/sec.  Then this rule will guarantee
 300Kbits/sec to UDP flows.  However, if the interface bandwidth was
 instead only 64kbits/sec, then this rule would correspondingly
 guarantee 19.2kb/sec.
 This policy is modeled within QPIM using two policy rules of the
 form:
    If (IP protocol is UDP) THEN (guarantee 30% of available BW) (1)
    If (IP protocol is TCP) THEN (guarantee 40% of available BW) (2)
 Assume that these two rules are grouped within a PolicySet [PCIMe]
 carrying the appropriate role combination.  A possible implementation
 of these rules within a PEP would be to use a Weighted-Round-Robin
 scheduler with 3 queues.  The first queue would be used for UDP
 traffic, the second queue for TCP traffic and the third queue for the
 rest of the traffic.  The weights of the Weighted-Round-Robin
 scheduler would be 30% for the first queue, 40% for the second queue
 and 30% for the last queue.
 The actions specifying the bandwidth guarantee implicitly assume that
 the bandwidth resource being guaranteed is the bandwidth available at
 the interface level.  A PolicyRoleCollection is a class defined in
 [PCIMe] whose purpose is to identify the set of resources (in this
 example, interfaces) that are assigned to a particular role.  Thus,
 the type of managed elements aggregated within the
 PolicyRoleCollection defines the bandwidth resource being controlled.
 In our example, interfaces are aggregated within the
 PolicyRoleCollection.  Therefore, the rules specify bandwidth
 allocation to all interfaces that match a given role.  Other behavior
 could be similarly defined by changing what was aggregated within the
 PolicyRoleCollection.
 Normally, a full specification of the rules would require indicating
 the direction of the traffic for which bandwidth allocation is being
 made.  Using the direction variable defined in [PCIMe], the rules can
 be specified in the following form:
    If (direction is out)
        If (IP protocol is UDP) THEN (guarantee 30% of available BW)
        If (IP protocol is TCP) THEN (guarantee 40% of available BW)
 where indentation is used to indicate rule nesting.  To save space,
 we omit the direction condition from further discussion.

Snir, et al. Standards Track [Page 18] RFC 3644 Policy QoS Information Model November 2003

 Rule nesting provides the ability to further refine the scope of
 bandwidth allocation within a given traffic class forwarded via these
 interfaces.  The example below adds two nested rules to refine
 bandwidth allocation for UDP and TCP applications.
    If (IP protocol is UDP) THEN (guarantee 30% of available BW) (1)
       If (protocol is TFTP) THEN (guarantee 10% of available BW) (1a)
       If (protocol is NFS) THEN (guarantee 40% of available BW) (1b)
    If (IP protocol is TCP) THEN (guarantee 40% of available BW) (2)
       If (protocol is HTTP) THEN guarantee 20% of available BW) (2a)
       If (protocol is FTP) THEN (guarantee 30% of available BW) (2b)
 Subrules 1a and 1b specify bandwidth allocation for UDP applications.
 The total bandwidth resource being partitioned among UDP applications
 is the bandwidth available for the UDP traffic class (i.e., 30%), not
 the total bandwidth available at the interface level.  Furthermore,
 TFTP and NFS are guaranteed to get at least 10% and 40% of the total
 available bandwidth for UDP, while other UDP applications aren't
 guaranteed to receive anything.  Thus, TFTP and NFS are guaranteed to
 get at least 3% and 12% of the total bandwidth.  Similar logic
 applies to the TCP applications.
 The point of this section will be to show that a hierarchical policy
 representation enables a finer level of granularity for bandwidth
 allocation to be specified than is otherwise available using a non-
 hierarchical policy representation.  To see this, let's compare this
 set of rules with a non-hierarchical (flat) rule representation.  In
 the non-hierarchical representation, the guaranteed bandwidth for
 TFTP flows is calculated by taking 10% of the bandwidth guaranteed to
 UDP flows, resulting in 3% of the total interface bandwidth
 guarantee.
    If (UDP AND TFTP) THEN (guarantee 3% of available BW) (1a)
    If (UDP AND NFS) THEN (guarantee 12% of available BW) (1b)
    If (other UDP APPs) THEN (guarantee 15% of available BW) (1c)
    If (TCP AND HTTP) THEN guarantee 8% of available BW) (2a)
    If (TCP AND FTP) THEN (guarantee 12% of available BW) (2b)
    If (other TCP APPs) THEN (guarantee 20% of available BW) (2c)
 Are these two representations identical?  No, bandwidth allocation is
 not the same.  For example, within the hierarchical representation,
 UDP applications are guaranteed 30% of the bandwidth.  Suppose a
 single UDP flow of an application different from NFS or TFTP is
 running.  This application would be guaranteed 30% of the interface
 bandwidth in the hierarchical representation but only 15% of the
 interface bandwidth in the flat representation.

Snir, et al. Standards Track [Page 19] RFC 3644 Policy QoS Information Model November 2003

 A two stage scheduler is best modeled by a hierarchical
 representation whereas a flat representation may be realized by a
 non-hierarchical scheduler.
 A schematic hierarchical Weighted-Round-Robin scheduler
 implementation that supports the hierarchical rule representation is
 described below.
  1. -UDP AND TFTP queue–10%
  2. -UDP AND NFS queue–40%-Scheduler-30%–+
  3. -Other UDP queue–50% A1 |

|

  1. -TCP AND HTTP queue–20% |
  2. -TCP AND FTP queue–30%-Scheduler-40%–Scheduler–Interface
  3. -Other TCP queue–50% A2 | B

|

  1. ———–Non UDP/TCP traffic—–30%–+
 Scheduler A1 extracts packets from the 3 UDP queues according to the
 weight specified by the UDP sub-rule policy.  Scheduler A2 extracts
 packets from the 3 TCP queues specified by the TCP sub-rule policy.
 The second stage scheduler B schedules between UDP, TCP and all other
 traffic according to the policy specified in the top most rule level.
 Another difference between the flat and hierarchical rule
 representation is the actual division of bandwidth above the minimal
 bandwidth guarantee.  Suppose two high rate streams are being
 forwarded via this interface: an HTTP stream and an NFS stream.
 Suppose that the rate of each flow is far beyond the capacity of the
 interface.  In the flat scheduler implementation, the ratio between
 the weights is 8:12 (i.e., HTTP:NFS), and therefore HTTP stream would
 consume 40% of the bandwidth while NFS would consume 60% of the
 bandwidth.  In the hierarchical scheduler implementation the only
 scheduler that has two queues filled is scheduler B, therefore the
 ratio between the HTTP (TCP) stream and the NFS (UDP) stream would be
 30:40, and therefore the HTTP stream would consume approximately 42%
 of the interface bandwidth while NFS would consume 58% of the
 interface bandwidth.  In both cases both HTTP and NFS streams got
 more than the minimal guaranteed bandwidth, but the actual rates
 forwarded via the interface differ.
 The conclusion is that hierarchical policy representation provides
 additional structure and context beyond the flat policy
 representation.  Furthermore, policies specifying bandwidth
 allocation using rule hierarchies should be enforced using
 hierarchical schedulers where the rule hierarchy level is mapped to
 the hierarchical scheduler level.

Snir, et al. Standards Track [Page 20] RFC 3644 Policy QoS Information Model November 2003

1.4.2. Use of Rule Hierarchy to Describe Drop Threshold Policies

 Two major resources govern the per hop behavior in each node.  The
 bandwidth allocation resource governs the forwarding behavior of each
 traffic class.  A scheduler priority and weights are controlled by
 the bandwidth allocation policies, as well as the (minimal) number of
 queues needed for traffic separation.  A second resource, which is
 not controlled by bandwidth allocation policies, is the queuing
 length and drop behavior.  For this purpose, queue length and
 threshold policies are used.
 Rule hierarchy is used to describe the context on which thresholds
 act.  The policy rule's condition describes the traffic class and the
 rule's actions describe the bandwidth allocation, the forwarding
 priority and the queue length.  If the traffic class contains
 different drop precedence sub-classes that require different
 thresholds within the same queue, the sub-rules actions describe
 these thresholds.
 Below is an example of the use of rule nesting for threshold control
 purposes.  Let's look at the following rules:
    If (protocol is FTP) THEN (guarantee 10% of available BW)
                              (queue length equals 40 packets)
                              (drop technique is random)
       if (src-ip is from net 2.x.x.x) THEN min threshold = 30%
                                            max threshold = 70%
       if (src-ip is from net 3.x.x.x) THEN min threshold = 40%
                                            max threshold = 90%
       if (all other)                  THEN min threshold = 20%
                                                  max threshold = 60%
 The rule describes the bandwidth allocation, the queue length and the
 drop technique assigned to FTP flows.  The sub-rules describe the
 drop threshold priorities within those FTP flows.  FTP packets
 received from all networks apart from networks 2.x.x.x and 3.x.x.x
 are randomly dropped when the queue threshold for FTP flows
 accumulates to 20% of the queue length.  Once the queue fills to 60%,
 all these packets are dropped before queuing.  The two other sub
 rules provide other thresholds for FTP packets coming from the
 specified two subnets.  The Assured Forwarding per hop behavior (AF)
 is another good example of the use of hierarchy to describe the
 different drop preferences within a traffic class.  This example is
 provided in a later section.

Snir, et al. Standards Track [Page 21] RFC 3644 Policy QoS Information Model November 2003

1.4.3. Restrictions of the Use of Hierarchy Within QPIM

 Rule nesting is used within QPIM for two important purposes:
 1) Enhance clarity, readability and reusability.
 2) Provide hierarchical context for actions.
 The second point captures the ability to specify context for
 bandwidth allocation, as well as providing context for drop threshold
 policies.
 When is a hierarchy level supposed to specify the bandwidth
 allocation context, when is the hierarchy used for specifying the
 drop threshold context, and when is it used merely for clarity and
 reusability?  The answer depends entirely on the actions.  Bandwidth
 control actions within a sub-rule specify how the bandwidth allocated
 to the traffic class determined by the rule's condition clause should
 be further divided among the sub-rules.  Drop threshold actions
 control the traffic class's queue drop behavior for each of the sub-
 rules.  The bandwidth control actions have an implicit pointer
 saying: the bandwidth allocation is relative to the bandwidth
 resources defined by the higher level rule. Drop threshold actions
 have an implicit pointer saying: the thresholds are taken from the
 queue resources defined by the higher level rule. Other actions do
 not have such an implicit pointer, and for these actions hierarchy is
 used only for reusability and readability purposes.
 Each rule that includes a bandwidth allocation action implies that a
 queue should be allocated to the traffic class defined by the rule's
 condition clause.  Therefore, once a bandwidth allocation action
 exists within the actions of a sub-rule, a threshold action within
 this sub-rule cannot refer to thresholds of the parent rule's queue.
 Instead, it must refer to the queue of the sub-rule itself.
 Therefore, in order to have a clear and unambiguous definition,
 refinement of thresholds and refinements of bandwidth allocations
 within sub-rules should be avoided.  If both refinements are needed
 for the same rule, threshold refinements and bandwidth refinements
 rules should each be aggregated to a separate group, and these groups
 should be aggregated under the policy rule, using the
 PolicySetComponent aggregation.

Snir, et al. Standards Track [Page 22] RFC 3644 Policy QoS Information Model November 2003

1.5. Intended Audiences

 QPIM is intended for several audiences.  The following lists some of
 the intended audiences and their respective uses:
 1. Developers of QoS policy management applications can use this
    model as an extensible framework for defining policies to control
    PEPs and PDPs in an interoperable manner.
 2. Developers of Policy Decision Point (PDP) systems built to control
    resource allocation signaled by RSVP requests.
 3. Developers of Policy Decision Points (PDP) systems built to create
    QoS configuration for PEPs.
 4. Builders of large organization data and knowledge bases who decide
    to combine QoS policy information with other networking policy
    information, assuming all modeling is based on [PCIM] and [PCIMe].
 5. Authors of various standards may use constructs introduced in this
    document to enhance their work.  Authors of data models wishing to
    map a storage specific technology to QPIM must use this document
    as well.

2. Class Hierarchies

2.1. Inheritance Hierarchy

 QPIM's class and association inheritance hierarchies are rooted in
 [PCIM] and [PCIMe].  Figures 2 and 3 depict these QPIM inheritance
 hierarchies, while noting their relationships to [PCIM] and
 [PCIMe]classes.  Note that many other classes used to form QPIM
 policies, such as SimplePolicyCondition, are defined in [PCIM] and
 [PCIMe].  Thus, the following figures do NOT represent ALL necessary
 classes and relationships for defining QPIM policies.  Rather, the
 designer using QPIM should use appropriate classes and relationships
 from [PCIM] and [PCIMe] in conjunction with those defined below.

Snir, et al. Standards Track [Page 23] RFC 3644 Policy QoS Information Model November 2003

[ManagedElement] (abstract, PCIM)

 |
 +--Policy (abstract, PCIM)
 |  |
 |  +---PolicyAction (abstract, PCIM)
 |  |     |
 |  |     +---SimplePolicyAction (PCIMe)
 |  |     |   |
 |  |     |   +---QoSPolicyRSVPSimpleAction (QPIM)
 |  |     |
 |  |     +---QoSPolicyDiscardAction (QPIM)
 |  |     |
 |  |     +---QoSPolicyAdmissionAction (abstract, QPIM)
 |  |     |   |
 |  |     |   +---QoSPolicyPoliceAction (QPIM)
 |  |     |   |
 |  |     |   +---QoSPolicyShapeAction (QPIM)
 |  |     |   |
 |  |     |   +---QoSPolicyRSVPAdmissionAction (QPIM)
 |  |     |
 |  |     +---QoSPolicyPHBAction (abstract, QPIM)
 |  |         |
 |  |         +---QoSPolicyBandwidthAction (QPIM)
 |  |         |
 |  |         +---QoSPolicyCongestionControlAction (QPIM)
 |  |
 |  +---QoSPolicyTrfcProf (abstract, QPIM)
 |  |   |
 |  |   +---QoSPolicyTokenBucketTrfcProf (QPIM)
 |  |   |
 |  |   +---QoSPolicyIntServTrfcProf (QPIM)
 |  |
 |  |
 |  +---PolicyVariable (abstract, PCIMe)
 |  |   |
 |  |   +---PolicyImplicitVariable (abstract, PCIMe)
 |  |       |
 |  |       +---QoSPolicyRSVPVariable (abstract, QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPSourceIPv4Variable (QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPDestinationIPv4Variable (QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPSourceIPv6Variable (QPIM)
 |  |           |

(continued on the next page)

Snir, et al. Standards Track [Page 24] RFC 3644 Policy QoS Information Model November 2003

(continued from the previous page)

[ManagedElement] (abstract, PCIM, repeated for convenience)

 |
 +--Policy (abstract, PCIM, repeated for convenience)
 |  |
 |  +---PolicyVariable (abstract, PCIMe)
 |  |   |
 |  |   +---PolicyImplicitVariable (abstract, PCIMe)
 |  |       |
 |  |       +---QoSPolicyRSVPVariable (abstract, QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPDestinationIPv6Variable (QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPSourcePortVariable (QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPDestinationPortVariable (QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPIPProtocolVariable (QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPIPVersionVariable (QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPDCLASSVariable (QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPStyleVariable (QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPDIntServVariable (QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPMessageTypeVariable (QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPPreemptionPriorityVariable (QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPPreemptionDefPriorityVariable (QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPUserVariable (QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPApplicationVariable (QPIM)
 |  |           |
 |  |           +---QoSPolicyRSVPAuthMethodVariable (QPIM)
 |  |
 |  +---PolicyValue (abstract, PCIMe)
 |  |     |
 |  |     +---QoSPolicyDNValue (QPIM)
 |  |     |
 |  |     +---QoSPolicyAttributeValue (QPIM)
          Figure 2.  The QPIM Class Inheritance Hierarchy

Snir, et al. Standards Track [Page 25] RFC 3644 Policy QoS Information Model November 2003

2.2. Relationship Hierarchy

 Figure 3 shows the QPIM relationship hierarchy.
 [unrooted] (abstract, PCIM)
   |
   +---Dependency (abstract)
   |   |
   |   +--- QoSPolicyTrfcProfInAdmissionAction (QPIM)
   |   |
   |   +--- QoSPolicyConformAction (QPIM)
   |   |
   |   +--- QoSPolicyExceedAction (QPIM)
   |   |
   |   +--- QoSPolicyViolateAction (QPIM)
   |   |
   |   +--- PolicyVariableInSimplePolicyAction
   |   |       |
   |   |       + QoSPolicyRSVPVariableInRSVPSimplePolicyAction
      Figure 3.  The QPIM Association Class Inheritance Hierarchy

3. QoS Actions

 This section describes the QoS actions that are modeled by QPIM.  QoS
 actions are policy enforced network behaviors that are specified for
 traffic selected by QoS conditions.  QoS actions are modeled using
 the classes PolicyAction (defined in [PCIM]), SimplePolicyAction
 (defined in [PCIMe]) and several QoS actions defined in this document
 that are derived from both of these classes, which are described
 below.
 Note that there is no discussion of PolicyRule, PolicyGroup, or
 different types of PolicyCondition classes in this document.  This is
 because these classes are fully specified in [PCIM] and [PCIMe].

3.1. Overview

 QoS policy based systems allow the network administrator to specify a
 set of rules that control both the selection of the flows that need
 to be provided with a preferred forwarding treatment, as well as
 specifying the specific set of preferred forwarding behaviors.  QPIM
 provides an information model for specifying such a set of rules.
 QoS policy rules enable controlling environments in which RSVP
 signaling is used to request different forwarding treatment for
 different traffic types from the network, as well as environments
 where no signaling is used, but preferred treatment is desired for

Snir, et al. Standards Track [Page 26] RFC 3644 Policy QoS Information Model November 2003

 some (but not all) traffic types.  QoS policy rules also allow
 controlling environments where strict QoS guarantees are provided to
 individual flows, as well as environments where QoS is provided to
 flow aggregates.  QoS actions allow a PDP or a PEP to determine which
 RSVP requests should be admitted before network resources are
 allocated.  QoS actions allow control of the RSVP signaling content
 itself, as well as differentiation between priorities of RSVP
 requests.  QoS actions allow controlling the Differentiated Service
 edge enforcement including policing, shaping and marking, as well as
 the per-hop behaviors used in the network core.  Finally, QoS actions
 can be used to control mapping of RSVP requests at the edge of a
 differentiated service cloud into per hop behaviors.
 Four groups of actions are derived from action classes defined in
 [PCIM] and [PCIMe].  The first QoS action group contains a single
 action, QoSPolicyRSVPSimpleAction.  This action is used for both RSVP
 signal control and install actions.  The second QoS action group
 determines whether a flow or class of flows should be admitted.  This
 is done by specifying an appropriate traffic profile using the
 QoSPolicyTrfcProf class and its subclasses.  This set of actions also
 includes QoS admission control actions, which use the
 QoSPolicyAdmissionAction class and its subclasses.  The third group
 of actions control bandwidth allocation and congestion control
 differentiations, which together specify the per-hop behavior
 forwarding treatment.  This group of actions includes the
 QoSPolicyPHBAction class and its subclasses.  The fourth QoS action
 is an unconditional packet discard action, which uses the
 QoSPolicyDiscardAction class.  This action is used either by itself
 or as a building block of the QoSPolicyPoliceAction.
 Note that some QoS actions are not directly modeled.  Instead, they
 are modeled by using the class SimplePolicyAction with the
 appropriate associations.  For example, the three marking actions
 (DSCP, IPP and CoS) are modeled by using the SimplePolicyAction
 class, and associating that class with variables and values of the
 appropriate type defined in [PCIMe].

3.2. RSVP Policy Actions

 There are three types of decisions a PDP (either remote or within a
 PEP) can make when it evaluates an RSVP request:
 1.  Admit or reject the request
 2.  Add or modify the request admission parameters
 3.  Modify the RSVP signaling content

Snir, et al. Standards Track [Page 27] RFC 3644 Policy QoS Information Model November 2003

 The COPS for RSVP [RFC2749] specification uses different Decision
 object types to model each of these decisions.  QPIM follows the COPS
 for RSVP specification and models each decision using a different
 action class.
 The QoSPolicyRSVPAdmissionAction controls the Decision Command and
 Decision Flags objects used within COPS for RSVP.  The
 QoSPolicyRSVPAdmissionAction class, with its associated
 QoSPolicyIntServTrfcProf class, is used to determine whether to
 accept or reject a given RSVP request by comparing the RSVP request's
 TSPEC or RSPEC parameters against the traffic profile specified by
 the QoSPolicyIntServTrfcProf.  For a full description of the
 comparison method, see section 4.  Following the COPS for RSVP
 specification, the admission decision has an option to both accept
 the request and send a warning to the requester.  The
 QoSPolicyRSVPAdmissionAction can be used to limit the number of
 admitted reservations as well.
 The class QoSPolicyRSVPSimpleAction, which is derived from the
 PolicySimpleAction class [PCIMe], can be used to control the two
 other COPS RSVP decision types.  The property qpRSVPActionType
 designates the instance of the class to be either of type 'REPLACE',
 'STATELESS', or both ('REPLACEANDSTATELESS').  For instances carrying
 a qpRSVPActionType property value of 'REPLACE', the action is
 interpreted as a COPS Replace Decision, controlling the contents of
 the RSVP message.  For instances carrying a qpRSVPActionType property
 value of 'STATELESS', the action is interpreted as a COPS Stateless
 Decision, controlling the admission parameters.  If both of these
 actions are required, this can be done by assigning the value
 REPLACEANDSTATELESS to the qpRSVPActionType property.
 This class is modeled to represent the COPS for RSVP Replace and
 Stateless decisions.  This similarity allows future use of these COPS
 decisions to be directly controlled by a QoSPolicySimpleAction.  The
 only required extension might be the definition of a new RSVP
 variable.

3.2.1. Example: Controlling COPS Stateless Decision

 The QoSPolicyRSVPSimpleAction allows the specification of admission
 parameters.  It allows specification of the preemption priority
 [RFC3181] of a given RSVP Reservation request.  Using the preemption
 priority value, the PEP can determine the importance of a Reservation
 compared with already admitted reservations, and if necessary can
 preempt lower priority reservations to make room for the higher
 priority one.  This class can also be used to control mapping of RSVP
 requests to a differentiated services domain by setting the

Snir, et al. Standards Track [Page 28] RFC 3644 Policy QoS Information Model November 2003

 QoSPolicyRSVPDCLASSVariable to the required value.  This instructs
 the PEP to mark traffic matching the Session and Sender
 specifications carried in an RSVP request to a given DSCP value.

3.2.2. Example: Controlling the COPS Replace Decision

 A Policy system should be able to control the information carried in
 the RSVP messages.  The QoSPolicyRSVPSimpleAction allows control of
 the content of RSVP signaling messages.  An RSVP message can carry a
 preemption policy object [RFC3181] specifying the priority of the
 reservation request in comparison to other requests.  An RSVP message
 can also carry a policy object for authentication purposes.  An RSVP
 message can carry a DCLASS [DCLASS] object that specifies to the
 receiver or sender the particular DSCP value that should be set on
 the data traffic.  A COPS for RSVP Replacement Data Decision controls
 the content of the RSVP message by specifying a set of RSVP objects
 replacing or removing the existing ones.

3.3. Provisioning Policy Actions

 The differentiated Service Architecture [DIFFSERV] was designed to
 provide a scalable QoS differentiation without requiring any
 signaling protocols running between the hosts and the network.  The
 QoS actions modeled in QPIM can be used to control all of the
 building blocks of the Differentiated Service architecture, including
 per-hop behaviors, edge classification, and policing and shaping,
 without a need to specify the datapath mechanisms used by PEP
 implementations.  This provides an abstraction level hiding the
 unnecessary details and allowing the network administrator to write
 rules that express the network requirements in a more natural form.
 In this architecture, as no signaling between the end host and the
 network occurs before the sender starts sending information, the QoS
 mechanisms should be set up in advance.  This usually means that PEPs
 need to be provisioned with the set of policy rules in advance.
 Policing and Shaping actions are modeled as subclasses of the QoS
 admission action.  DSCP and CoS marking are modeled by using the
 SimplePolicyAction ([PCIMe]) class associated with the appropriate
 variables and values.  Bandwidth allocation and congestion control
 actions are modeled as subclasses of the QpQPolicyPHBAction, which is
 itself a subclass PolicyAction class ([PCIM])

3.3.1. Admission Actions: Controlling Policers and Shapers

 Admission Actions (QoSPolicyAdmissionAction and its subclasses) are
 used to police and/or shape traffic.

Snir, et al. Standards Track [Page 29] RFC 3644 Policy QoS Information Model November 2003

 Each Admission Action is bound to a traffic profile
 (QoSPolicyTrfcProf) via the QoSPolicyTrfcProfInAdmissionAction
 association.  The traffic profile is used to meter traffic for
 purposes of policing or shaping.
 An Admission Action carries a scope property (qpAdmissionScope) that
 is used to determine whether the action controls individual traffic
 flows or aggregate traffic classes.  The concepts of "flow" and
 "traffic class" are explained in [DIFFSERV] using the terms
 'microflow' and 'traffic stream'.  Roughly speaking, a flow is a set
 of packets carrying an IP header that has the same values for source
 IP, destination IP, protocol and layer 4 source and destination
 ports.  A traffic class is a set of flows.  In QPIM, simple and
 compound conditions can identify flows and/or traffic classes by
 using Boolean terms over the values of IP header fields, including
 the value of the ToS byte.
 Thus, the interpretation of the scope property is as follows: If the
 value of the scope property is 0 (per-flow), each (micro) flow that
 can be positively matched with the rule's condition is metered and
 policed individually.  If the value of the scope property is 1 (per-
 class), all flows matched with the rule's condition are metered as a
 single aggregate and policed together.
 The following example illustrates the use of the scope property.
 Using two provisioned policing actions, the following policies can be
 enforced:
  1. Make sure that each HTTP flow will not exceed 64kb/s
  1. Make sure that the aggregate rate of all HTTP flows will not

exceed 512Kb/s

 Both policies are modeled using the same class QoSPolicyPoliceAction
 (derived from QoSPolicyAdmissionAction).  The first policy has its
 scope property set to 'flow', while the second policy has its scope
 property set to 'class'.  The two policies are modeled using a rule
 with two police actions that, in a pseudo-formal definition, looks
 like the following:
    If (HTTP) Action1=police, Traffic Profile1=64kb/s, Scope1=flow
              Action2=police, Traffic Profile2=512kb/s, Scope2=class
 The provisioned policing action QoSPolicyPoliceAction has three
 associations, QoSPolicyConformAction, QoSPolicyExceedAction and
 QoSPolicyViolateAction.

Snir, et al. Standards Track [Page 30] RFC 3644 Policy QoS Information Model November 2003

 To accomplish the desired result stated above, two possible modeling
 techniques may be used: The two actions can be part of a single
 policy rule using two PolicyActionInPolicyRule [PCIM] associations.
 In this case the ExecutionStrategy property of the PolicyRule class
 [PCIMe] SHOULD be set to "Do All" so that both individual flows and
 aggregate streams are policed.
 Alternatively, Action1 and Action2 could be aggregated in a
 CompundPolicyAction instance using the PolicyActionInPolicyAction
 aggregations [PCIMe].  In this case, in order for both individual
 flows and aggregate traffic classes to be policed, the
 ExecutionStrategy property of the CompoundPolicyAction class [PCIMe]
 SHOULD be set to "Do All".
 The policing action is associated with a three-level token bucket
 traffic profile carrying rate, burst and excess-burst parameters.
 Traffic measured by a meter can be classified as conforming traffic
 when the metered rate is below the rate defined by the traffic
 profile, as excess traffic when the metered traffic is above the
 normal burst and below the excess burst size, and violating traffic
 when rate is above the maximum excess burst.
 The [DIFF-MIB] defines a two-level meter, and provides a means to
 combine two-level meters into more complex meters.  In this document,
 a three-level traffic profile is defined.  This allows construction
 of both two-level meters as well as providing an easier definition
 for three-level meters needed for creating AF [AF] provisioning
 actions.
 A policing action that models three-level policing MUST associate
 three separate actions with a three-level traffic profile.  These
 actions are a conforming action, an exceeding action and a violating
 action.  A policing action that models two-level policing uses a
 two-level traffic profile and associates only conforming and
 exceeding actions.  A policing action with a three-level traffic
 profile that specifies an exceed action but does not specify a
 violate action implies that the action taken when the traffic is
 above the maximum excess burst is identical to the action taken when
 the traffic is above the normal burst.  A policer determines whether
 the profile is being met, while the actions to be performed are
 determined by the associations QoSPolicyXXXAction.
 Shapers are used to delay some or all of the packets in a traffic
 stream, in order to bring the stream into compliance with a traffic
 profile.  A shaper usually has a finite-sized buffer, and packets may
 be discarded if there is not sufficient buffer space to hold the
 delayed packets.  Shaping is controlled by the QoSPolicyShapeAction

Snir, et al. Standards Track [Page 31] RFC 3644 Policy QoS Information Model November 2003

 class.  The only required association is a traffic profile that
 specifies the rate and burst parameters that the outgoing flows
 should conform with.

3.3.2. Controlling Markers

 Three types of marking control actions are modeled in QPIM:
 Differentiated Services Code Point (DSCP) assignment, IP Precedence
 (IPP) assignment and layer-2 Class of Service (CoS) assignment.
 These assignment actions themselves are modeled by using the
 SimplePolicyAction class associated with the appropriate variables
 and values.
 DSCP assignment sets ("marks" or "colors") the DS field of a packet
 header to a particular DS Code Point (DSCP), adding the marked packet
 to a particular DS behavior aggregate.
 When used in the basic form, "If <condition> then 'DCSP = ds1'", the
 assignment action assigns a DSCP value (ds1) to all packets that
 result in the condition being evaluated to true.
 When used in combination with a policing action, a different
 assignment action can be issued via each of the 'conform', 'exceed'
 and 'violate' action associations.  This way, one may select a PHB in
 a PHB group according to the state of a meter.
 The semantics of the DSCP assignment is encapsulated in the pairing
 of a DSCP variable and a DSCP value within a single
 SimplePolicyAction instance via the appropriate associations.
 IPP assignment sets the IPP field of a packet header to a particular
 IPP value (0 through 7).  The semantics of the IPP assignment is
 encapsulated in the pairing of a ToS variable (PolicyIPTosVariable)
 and a bit string value () (defined in [PCIMe]) within a single
 SimplePolicyAction instance via the appropriate associations.  The
 bit string value is used in its masked bit string format.  The mask
 indicates the relevant 3 bits of the IPP sub field within the ToS
 byte, while the bit string indicates the IPP value to be set.
 CoS assignments control the mapping of a per-hop behavior to a
 layer-2 Class of Service.  For example, mapping of a set of DSCP
 values into a 802.1p user priority value can be specified using a
 rule with a condition describing the set of DSCP values, and a CoS
 assignment action that specifies the required mapping to the given
 user priority value. The semantics of the CoS assignment is
 encapsulated in the pairing of a CoS variable and a CoS value
 (integer in the range of 0 through 7) within a single
 SimplePolicyAction instance via the appropriate associations.

Snir, et al. Standards Track [Page 32] RFC 3644 Policy QoS Information Model November 2003

3.3.3. Controlling Edge Policies - Examples

 Assuming that the AF1 behavior aggregate is enforced within a DS
 domain, policy rules on the boundaries of the network should mark
 packets to one of the AF1x DSCPs, depending on the conformance of the
 traffic to a predetermined three-parameter traffic profile.  QPIM
 models such AF1 policing action as defined in Figure 4.
   +-----------------------+    +------------------------------+
   | QoSPolicyPoliceAction |====| QoSPolicyTokenBucketTrfcProf |
   | scope = class         |    | rate = x, bc = y, be = z     |
   +-----------------------+    +------------------------------+
     *     @     #
     *     @     #
     *     @  +--------------------+   +--------------------------+
     *     @  | SimplePolicyAction |---| PolicyIntegerValue -AF13 |
     *     @  +--------------------+   +--------------------------+
     *     @
     *  +--------------------+   +---------------------------+
     *  | SimplePolicyAction |---| PolicyIntegerValue - AF12 |
     *  +--------------------+   +---------------------------+
     *
   +--------------------+   +---------------------------+
   | SimplePolicyAction |---| PolicyIntegerValue - AF11 |
   +--------------------+   +---------------------------+
 Association and Aggregation Legend:
  • * QoSPolicyConformAction @@@@ QoSPolicyExceedAction #### QoSPolicyViolateAction ==== QoSTrfcProfInAdmissionAction —- PolicyValueInSimplePolicyAction ([PCIMe]) &&&& PolicyVariableInSimplePolicyAction ([PCIMe], not shown) Figure 4. AF Policing and Marking The AF policing action is composed of a police action, a token bucket traffic profile and three instances of the SimplePolicyAction class. Each of the simple policy action instances models a different marking action. Each SimplePolicyAction uses the aggregation PolicyVariableInSimplePolicyAction to specify that the associated PolicyDSCPVariable is set to the appropriate integer value. This is done using the PolicyValueInSimplePolicyAction aggregation. The three PolicyVariableInSimplePolicyAction aggregations which connect the appropriate SimplePolicyActions with the appropriate DSCP Snir, et al. Standards Track [Page 33] RFC 3644 Policy QoS Information Model November 2003 Variables, are not shown in this figure for simplicity. AF11 is marked on detecting conforming traffic; AF12 is marked on detecting exceeding traffic, and AF13 on detecting violating traffic. The second example, shown in Figure 5, is the simplest policing action. Traffic below a two-parameter traffic profile is unmodified, while traffic exceeding the traffic profile is discarded. +———————–+ +——————————+ | QoSPolicyPoliceAction |====| QoSPolicyTokenBucketTrfcProf | | scope = class | | rate = x, bc = y | +———————–+ +——————————+ @ @ +————————-+ | QoSPolicyDiscardAction | +————————-+ Association and Aggregation Legend: ** QoSPolicyConformAction (not used)

@@@@ QoSPolicyExceedAction

   ####  QoSPolicyViolateAction (not used)
   ====  QoSTrfcProfInAdmissionAction
 Figure 5.    A Simple Policing Action

3.4. Per-Hop Behavior Actions

 A Per-Hop Behavior (PHB) is a description of the externally
 observable forwarding behavior of a DS node applied to a particular
 DS behavior aggregate [DIFFSERV].  The approach taken here is that a
 PHB action specifies both observable forwarding behavior (e.g., loss,
 delay, jitter) as well as specifying the buffer and bandwidth
 resources that need to be allocated to each of the behavior
 aggregates in order to achieve this behavior.  That is, a rule with a
 set of PHB actions can specify that an EF packet must not be delayed
 more than 20 msec in each hop.  The same rule may also specify that
 EF packets need to be treated with preemptive forwarding (e.g., with
 priority queuing), and specify the maximum bandwidth for this class,
 as well as the maximum buffer resources.  PHB actions can therefore
 be used both to represent the final requirements from PHBs and to
 provide enough detail to be able to map the PHB actions into a set of
 configuration parameters to configure queues, schedulers, droppers
 and other mechanisms.
 The QoSPolicyPHBAction abstract class has two subclasses.  The
 QoSPolicyBandwidthAction class is used to control bandwidth, delay
 and forwarding behavior, while the QoSPolicyCongestionControlAction

Snir, et al. Standards Track [Page 34] RFC 3644 Policy QoS Information Model November 2003

 class is used to control queue size, thresholds and congestion
 algorithms.  The qpMaxPacketSize property of the QoSPolicyPHBAction
 class specifies the packet size in bytes, and is needed when
 translating the bandwidth and congestion control actions into actual
 implementation configurations. For example, an implementation
 measuring queue length in bytes will need to use this property to map
 the qpQueueSize property into the desired queue length in bytes.

3.4.1. Controlling Bandwidth and Delay

 QoSPolicyBandwidthAction allows specifying the minimal bandwidth that
 should be reserved for a class of traffic.  The property
 qpMinBandwidth can be specified either in Kb/sec or as a percentage
 of the total available bandwidth.  The property qpBandwidthUnits is
 used to determine whether percentages or fixed values are used.
 The property qpForwardingPriority is used whenever preemptive
 forwarding is required.  A policy rule that defines the EF PHB should
 indicate a non-zero forwarding priority.  The qpForwardingPriority
 property holds an integer value to enable multiple levels of
 preemptive forwarding where higher values are used to specify higher
 priority.
 The property qpMaxBandwidth specifies the maximum bandwidth that
 should be allocated to a class of traffic.  This property may be
 specified in PHB actions with non-zero forwarding priority in order
 to guard against starvation of other PHBs.
 The properties qpMaxDelay and qpMaxJitter specify limits on the per-
 hop delay and jitter in milliseconds for any given packet within a
 traffic class.  Enforcement of the maximum delay and jitter may
 require use of preemptive forwarding as well as minimum and maximum
 bandwidth controls.  Enforcement of low max delay and jitter values
 may also require fragmentation and interleave mechanisms over low
 speed links.
 The Boolean property qpFairness indicates whether flows should have a
 fair chance to be forwarded without drop or delay.  A way to enforce
 a bandwidth action with qpFairness set to TRUE would be to build a
 queue per flow for the class of traffic specified in the rule's
 filter.  In this way, interactive flows like terminal access will not
 be queued behind a bursty flow (like FTP) and therefore have a
 reasonable response time.

3.4.2. Congestion Control Actions

 The QoSPolicyCongestionControlAction class controls queue length,
 thresholds and congestion control algorithms.

Snir, et al. Standards Track [Page 35] RFC 3644 Policy QoS Information Model November 2003

 A PEP should be able to keep in its queues qpQueueSize packets
 matching the rule's condition.  In order to provide a link-speed
 independent queue size, the qpQueueSize property can also be measured
 in milliseconds.  The time interval specifies the time needed to
 transmit all packets within the queue if the link speed is dedicated
 entirely for transmission of packets within this queue.  The property
 qpQueueSizeUnit determines whether queue size is measured in number
 of packets or in milliseconds.  The property qpDropMethod selects
 either tail-drop, head-drop or random-drop algorithms.  The set of
 maximum and minimum threshold values can be specified as well, using
 qpDropMinThresholdValue and qpDropMaxThresholdValue properties,
 either in packets or in percentage of the total available queue size
 as specified by the qpDropThresholdUnits property.

3.4.3. Using Hierarchical Policies: Examples for PHB Actions

 Hierarchical policy definition is a primary tool in the QoS Policy
 information model.  Rule nesting introduced in [PCIMe] allows
 specification of hierarchical policies controlling RSVP requests,
 hierarchical shaping, policing and marking actions, as well as
 hierarchical schedulers and definition of the differences in PHB
 groups.
 This example provides a set of rules that specify PHBs enforced
 within a Differentiated Service domain.  The network administrator
 chose to enforce the EF, AF11 and AF13 and Best Effort PHBs.  For
 simplicity, AF12 is not differentiated.  The set of rules takes the
 form:
    If (EF) then do EF actions
    If (AF1) then do AF1 actions
        If (AF11) then do AF11 actions
        If (AF12) then do AF12 actions
        If (AF13) then do AF13 actions
    If (default) then do Default actions.
 EF, AF1, AF11, AF12 and AF13 are conditions that filter traffic
 according to DSCP values.  The AF1 condition matches the entire AF1
 PHB group including the AF11, AF12 and AF13 DSCP values.  The default
 rule specifies the Best Effort rules.  The nesting of the AF1x rules
 within the AF1 rule specifies that there are further refinements on
 how AF1x traffic should be treated relative to the entire AF1 PHB
 group.  The set of rules reside in a PolicyGroup with a decision
 strategy property set to 'FirstMatching'.
 The class instances below specify the set of actions used to describe
 each of the PHBs.  Queue sizes are not specified, but can easily be
 added to the example.

Snir, et al. Standards Track [Page 36] RFC 3644 Policy QoS Information Model November 2003

 The actions used to describe the Best Effort PHB are simple.  No
 bandwidth is allocated to Best Effort traffic.  The first action
 specifies that Best Effort traffic class should have fairness.
 QoSPolicyBandwidthAction  BE-B:
   qpFairness: TRUE
 The second action specifies that the congestion algorithm for the
 Best Effort traffic class should be random, and specifies the
 thresholds in percentage of the default queue size.
 QoSPolicyCongestionControlAction  BE-C:
   qpDropMethod: random
   qpDropThresholdUnits %
   qpDropMinThreshold:  10%
   qpDropMaxThreshold:  70%
 EF requires preemptive forwarding.  The maximum bandwidth is also
 specified to make sure that the EF class does not starve the other
 classes.  EF PHB uses tail drop as the applications using EF are
 supposed to be UDP-based and therefore would not benefit from a
 random dropper.
 QoSPolicyBandwidthAction  EF-B:
   qpForwardingPriority: 1
   qpBandwidthUnits: %
   qpMaxBandwidth  50%
   qpFairness: FALSE
 QoSPolicyCongestionControlAction  EF-C:
   qpDropMethod: tail-drop
   qpDropThresholdUnits packet
   qpDropMaxThreshold:  3 packets
 The AF1 actions define the bandwidth allocations for the entire PHB
 group:
 QoSPolicyBandwidthAction  AF1-B:
   qpBandwidthUnits: %
   qpMinBandwidth: 30%
 The AF1i actions specifies the differentiating refinement for the
 AF1x PHBs within the AF1 PHB group.  The different threshold values
 provide the difference in discard probability of the AF1x PHBs within
 the AF1 PHB group.

Snir, et al. Standards Track [Page 37] RFC 3644 Policy QoS Information Model November 2003

 QoSPolicyCongestionControlAction  AF11-C:
   qpDropMethod: random
   qpDropThresholdUnits packet
   qpDropMinThreshold:  6 packets
   qpDropMaxThreshold:  16 packets
 QoSPolicyCongestionControlAction  AF12-C:
   qpDropMethod: random
   qpDropThresholdUnits packet
   qpDropMinThreshold:  4 packets
   qpDropMaxThreshold:  13 packets
 QoSPolicyCongestionControlAction  AF13-C:
   qpDropMethod: random
   qpDropThresholdUnits packet
   qpDropMinThreshold:  2 packets
   qpDropMaxThreshold:  10 packets

4. Traffic Profiles

 Meters measure the temporal state of a flow or a set of flows against
 a traffic profile.  In this document, traffic profiles are modeled by
 the QoSPolicyTrfcProf class.  The association QoSPolicyTrfcProf
 InAdmissionAction binds the traffic profile to the admission action
 using it.  Two traffic profiles are derived from the abstract class
 QoSPolicyTrfcProf.  The first is a Token Bucket provisioning traffic
 profile carrying rate and burst parameters.  The second is an RSVP
 traffic profile, which enables flows to be compared with RSVP TSPEC
 and FLOWSPEC parameters.

4.1. Provisioning Traffic Profiles

 Provisioned Admission Actions, including shaping and policing, are
 specified using a two- or three-parameter token bucket traffic
 profile.  The QoSPolicyTokenBucketTrfcProf class includes the
 following properties:
 1.  Rate measured in kbits/sec
 2.  Normal burst measured in bytes
 3.  Excess burst measured in bytes
 Rate determines the long-term average transmission rate.  Traffic
 that falls under this rate is conforming, as long as the normal burst
 is not exceeded at any time.  Traffic exceeding the normal burst but
 still below the excess burst is exceeding the traffic profile.
 Traffic beyond the excess burst is said to be violating the traffic
 profile.

Snir, et al. Standards Track [Page 38] RFC 3644 Policy QoS Information Model November 2003

 Excess burst size is measured in bytes in addition to the burst size.
 A zero excess burst size indicates that no excess burst is allowed.

4.2. RSVP traffic profiles

 RSVP admission policy can condition the decision whether to accept or
 deny an RSVP request based on the traffic specification of the flow
 (TSPEC) or the amount of QoS resources requested (FLOWSPEC).  The
 admission decision can be based on matching individual RSVP requests
 against a traffic profile or by matching the aggregated sum of all
 FLOWSPECs (TSPECs) currently admitted, as determined by the
 qpAdmissionScope property in an associated
 QoSPolicyRSVPAdmissionAction.
 The QoSPolicyIntservTrfcProf class models both such traffic profiles.
 This class has the following properties:
    1.  Token Rate (r) measured in bits/sec
    2.  Peak Rate (p) measured in bits/sec
    3.  Bucket Size (b) measured in bytes
    4.  Min Policed unit (m) measured in bytes
    5.  Max packet size (M) measured in bytes
    6.  Resv Rate (R) measured in bits/sec
    7.  Slack term (s) measured in microseconds
 The first five parameters are the traffic specification parameters
 used in the Integrated Service architecture ([INTSERV]).  These
 parameters are used to define a sender TSPEC as well as a FLOWSPEC
 for the Controlled-Load service [CL].  For a definition and full
 explanation of their meanings, please refer to [RSVP-IS].
 Parameters 6 and 7 are the additional parameters used for
 specification of the Guaranteed Service FLOWSPEC [GS].
 A partial order is defined between TSPECs (and FLOWSPECs).  The TSPEC
 A is larger than the TSPEC B if and only if rA>rB, pA>pB, bA>bB,
 mA<mB and MA>MB.  A TSPEC (FLOWSPEC) measured against a traffic
 profile uses the same ordering rule.  An RSVP message is accepted
 only if its TSPEC (FLOWSPEC) is either smaller or equal to the
 traffic profile.  Only parameters specified in the traffic profile
 are compared.
 The GS FLOWSPEC is compared against the rate R and the slack term s.
 The term R should not be larger than the traffic profile R parameter,
 while the FLOWSPEC slack term should not be smaller than that
 specified in the slack term.

Snir, et al. Standards Track [Page 39] RFC 3644 Policy QoS Information Model November 2003

 TSPECs as well as FLOWSPECs can be added.  The sum of two TSPECs is
 computed by summing the rate r, the peak rate p, the bucket size b,
 and by taking the minimum value of the minimum policed unit m and the
 maximum value of the maximum packet size M.  GS FLOWSPECs are summed
 by adding the Resv rate and minimizing the slack term s.  These rules
 are used to compute the temporal state of admitted RSVP states
 matching the traffic class defined by the rule condition.  This state
 is compared with the traffic profile to arrive at an admission
 decision when the scope of the QoSPolicyRSVPAdmissionAction is set to
 'class'.

5. Pre-Defined QoS-Related Variables

 Pre-defined variables are necessary for ensuring interoperability
 among policy servers and policy management tools from different
 vendors.  The purpose of this section is to define frequently used
 variables in QoS policy domains.
 Notice that this section only adds to the variable classes as defined
 in [PCIMe] and reuses the mechanism defined there.
 The QoS policy information model specifies a set of pre-defined
 variable classes to support a set of fundamental QoS terms that are
 commonly used to form conditions and actions and are missing from the
 [PCIMe]. Examples of these include RSVP related variables.  All
 variable classes defined in this document extend the
 QoSPolicyRSVPVariable class (defined in this document), which itself
 extends the PolicyImplictVariable class, defined in [PCIMe].
 Subclasses specify the data type and semantics of the policy
 variables.
 This document defines the following RSVP variable classes; for
 details, see their class definitions:
 RSVP related Variables:
 1.   QoSPolicyRSVPSourceIPv4Variable - The source IPv4 address of the
      RSVP signaled flow, as defined in the RSVP PATH SENDER_TEMPLATE
      and RSVP RESV FILTER_SPEC [RSVP] objects.
 2.   QoSPolicyRSVPDestinationIPv4Variable - The destination port of
      the RSVP signaled flow, as defined in the RSVP PATH and RESV
      SESSION [RSVP] objects (for IPv4 traffic).
 3.   QoSPolicyRSVPSourceIPv6Variable - The source IPv6 address of the
      RSVP signaled flow, as defied in the RSVP PATH SENDER_TEMPLATE
      and RSVP RESV FILTER_SPEC [RSVP] objects.

Snir, et al. Standards Track [Page 40] RFC 3644 Policy QoS Information Model November 2003

 4.   QoSPolicyRSVPDestinationIPv6Variable - The destination port of
      the RSVP signaled flow, as defined in the RSVP PATH and RESV
      SESSION [RSVP] objects (for IPv6 traffic).
 5.   QoSPolicyRSVPSourcePortVariable - The source port of the RSVP
      signaled flow, as defined in the RSVP PATH SENDER_TEMPLATE and
      RSVP RESV FILTER_SPEC [RSVP] objects.
 6.   QoSPolicyRSVPDestinationPortVariable - The destination port of
      the RSVP signaled flow, as defined in the RSVP PATH and RESV
      SESSION [RSVP] objects.
 7.   QoSPolicyRSVPIPProtocolVariable - The IP Protocol of the RSVP
      signaled flow, as defined in the RSVP PATH and RESV SESSION
      [RSVP] objects.
 8.   QoSPolicyRSVPIPVersionVariable - The version of the IP addresses
      carrying the RSVP signaled flow, as defined in the RSVP PATH and
      RESV SESSION [RSVP] objects.
 9.   QoSPolicyRSVPDCLASSVariable - The DSCP value as defined in the
      RSVP DCLASS [DCLASS] object.
 10.  QoSPolicyRSVPStyleVariable - The reservation style (FF, SE, WF)
      as defined in the RSVP RESV message [RSVP].
 11.  QoSPolicyRSVPIntServVariable - The type of Integrated Service
      (CL, GS, NULL) requested in the RSVP Reservation message, as
      defined in the FLOWSPEC RSVP Object [RSVP].
 12.  QoSPolicyRSVPMessageTypeVariable - The RSVP message type, either
      PATH, PATHTEAR, RESV, RESVTEAR, RESVERR, CONF or PATHERR [RSVP].
 13.  QoSPolicyRSVPPreemptionPriorityVariable - The RSVP reservation
      priority as defined in [RFC3181].
 14.  QoSPolicyRSVPPreemptionDefPriorityVariable - The RSVP preemption
      reservation defending priority as defined in [RFC3181].
 15.  QoSPolicyRSVPUserVariable - The ID of the user that initiated
      the flow as defined in the User Locator string in the Identity
      Policy Object [RFC3182].
 16.  QoSPolicyRSVPApplicationVariable - The ID of the application
      that generated the flow as defined in the application locator
      string in the Application policy object [RFC2872].

Snir, et al. Standards Track [Page 41] RFC 3644 Policy QoS Information Model November 2003

 17.  QoSPolicyRSVPAuthMethodVariable - The RSVP Authentication type
      used in the Identity Policy Object [RFC3182].
 Each class restricts the possible value types associated with a
 specific variable.  For example, the QoSPolicyRSVPSourcePortVariable
 class is used to define the source port of the RSVP signaled flow.
 The value associated with this variable is of type
 PolicyIntegerValue.

6. QoS Related Values

 Values are used in the information model as building blocks for the
 policy conditions and policy actions, as described in [PCIM] and
 [PCIMe].  This section defines a set of auxiliary values that are
 used for QoS policies as well as other policy domains.
 All value classes extend the PolicyValue class [PCIMe].  The
 subclasses specify specific data/value types that are not defined in
 [PCIMe].
 This document defines the following two subclasses of the PolicyValue
 class:
 QoSPolicyDNValue          This class is used to represent a single or
                           set of Distinguished Name [DNDEF] values,
                           including wildcards.  A Distinguished Name
                           is a name that can be used as a key to
                           retrieve an object from a directory
                           service.  This value can be used in
                           comparison to reference values carried in
                           RSVP policy objects, as specified in
                           [RFC3182].  This class is defined in
                           Section 8.31.
 QoSPolicyAttributeValue   A condition term uses the form "Variable
                           matches Value", and an action term uses the
                           form "set Variable to Value" ([PCIMe]).
                           This class is used to represent a single or
                           set of property values for the "Value" term
                           in either a condition or an action. This
                           value can be used in conjunction with
                           reference values carried in RSVP objects,
                           as specified in [RFC3182].  This class is
                           defined in section 8.12.
 The property name is used to specify which of the properties in the
 QoSPolicyAttributeValue class instance is being used in the condition
 or action term.  The value of this property or properties will then

Snir, et al. Standards Track [Page 42] RFC 3644 Policy QoS Information Model November 2003

 be retrieved.  In the case of a condition, a match (which is
 dependent on the property name) will be used to see if the condition
 is satisfied or not.  In the case of an action, the semantics are
 instead "set the variable to this value".
 For example, suppose the "user" objects in the organization include
 several properties, among them:
  1. First Name
  2. Last Name
  3. Login Name
  4. Department
  5. Title
 A simple condition could be constructed to identify flows by their
 RSVP user carried policy object.  The simple condition: Last Name =
 "Smith" to identify a user named Bill would be constructed in the
 following way:
    A SimplePolicyCondition [PCIMe] would aggregate a
    QoSPolicyRSVPUserVariable [QPIM] object, via the
    PolicyVariableInSimplePolicyCondition [PCIMe] aggregation.
 The implicit value associated with this condition is created in the
 following way:
    A QoSPolicyAttributeValue object would be aggregated to the simple
    condition object via a PolicyValueInSimplePolicyCondition [PCIMe].
    The QoSPolicyAttributeValue attribute qpAttributeName would be set
    to "last name" and the qpAttributeValueList would be set to
    "Smith".
 Another example is a condition that has to do with the user's
 organizational department.  It can be constructed in the exact same
 way, by changing the QoSPolicyAttributeValue attribute
 qpAttributeName to "Department" and the qpAttributeValueList would be
 set to the particular value that is to be matched (e.g.,
 "engineering" or "customer support").  The logical condition would
 than be evaluated to true if the user belong to either the
 engineering department or the customer support.
 Notice that many multiple-attribute objects require the use of the
 QoSPolicyAttributeValue class to specify exactly which of its
 attributes should be used in the condition match operation.

Snir, et al. Standards Track [Page 43] RFC 3644 Policy QoS Information Model November 2003

7. Class Definitions: Association Hierarchy

 The following sections define associations that are specified by
 QPIM.

7.1. The Association "QoSPolicyTrfcProfInAdmissionAction"

 This association links a QoSPolicyTrfcProf object (defined in section
 8.9), modeling a specific traffic profile, to a
 QoSPolicyAdmissionAction object (defined in section 8.2).  The class
 definition for this association is as follows:
 NAME              QoSPolicyTrfcProfInAdmissionAction
 DESCRIPTION       A class representing the association between a
                   QoS admission action and its traffic profile.
 DERIVED FROM      Dependency (See [PCIM])
 ABSTRACT          FALSE
 PROPERTIES        Antecedent[ref QoSPolicyAdmissionAction [0..n]]
                   Dependent[ref QoSPolicyTrfcProf [1..1]]

7.1.1. The Reference "Antecedent"

 This property is inherited from the Dependency association, defined
 in [PCIM].  Its type is overridden to become an object reference to a
 QoSPolicyAdmissionAction object.  This represents the "independent"
 part of the association.  The [0..n] cardinality indicates that any
 number of QoSPolicyAdmissionAction object(s) may use a given
 QoSPolicyTrfcProf.

7.1.2. The Reference "Dependent"

 This property is inherited from the Dependency association, and is
 overridden to become an object reference to a QoSPolicyTrfcProf
 object.  This represents a specific traffic profile that is used by
 any number of QoSPolicyAdmissionAction objects.  The [1..1]
 cardinality means that exactly one object of the QoSPolicyTrfcProf
 can be used by a given QoSPolicyAddmissionAction.

7.2. The Association "PolicyConformAction"

 This association links a policing action with an object defining an
 action to be applied to conforming traffic relative to the associated
 traffic profile.  The class definition for this association is as
 follows:

Snir, et al. Standards Track [Page 44] RFC 3644 Policy QoS Information Model November 2003

 NAME              PolicyConformAction
 DESCRIPTION       A class representing the association between a
                   policing action and the action that should be
                   applied to traffic conforming to an associated
                   traffic profile.
 DERIVED FROM      Dependency (see [PCIM])
 ABSTRACT          FALSE
 PROPERTIES        Antecedent[ref QoSPolicyPoliceAction[0..n]]
                   Dependent[ref PolicyAction [1..1]]

7.2.1. The Reference "Antecedent"

 This property is inherited from the Dependency association.  Its type
 is overridden to become an object reference to a
 QoSPolicyPoliceAction object.  This represents the "independent" part
 of the association.  The [0..n] cardinality indicates that any number
 of QoSPolicyPoliceAction objects may be given the same action to be
 executed as the conforming action.

7.2.2. The Reference "Dependent"

 This property is inherited from the Dependency association, and is
 overridden to become an object reference to a PolicyAction object.
 This represents a specific policy action that is used by a given
 QoSPolicyPoliceAction.  The [1..1] cardinality means that exactly one
 policy action  can be used as the "conform" action for a
 QoSPolicyPoliceAction.  To execute more than one conforming action,
 use the PolicyCompoundAction class to model the conforming action.

7.3. The Association "QoSPolicyExceedAction"

 This association links a policing action with an object defining an
 action to be applied to traffic exceeding the associated traffic
 profile.  The class definition for this association is as follows:
 NAME              QoSPolicyExceedAction
 DESCRIPTION       A class representing the association between a
                   policing action and the action that should be
                   applied to traffic exceeding an associated traffic
                   profile.
 DERIVED FROM      Dependency (see [PCIM])
 ABSTRACT          FALSE
 PROPERTIES        Antecedent[ref QoSPolicePoliceAction[0..n]]
                   Dependent[ref PolicyAction [1..1]]

Snir, et al. Standards Track [Page 45] RFC 3644 Policy QoS Information Model November 2003

7.3.1. The Reference "Antecedent"

 This property is inherited from the Dependency association.  Its type
 is overridden to become an object reference to a
 QoSPolicyPoliceAction object.  This represents the "independent" part
 of the association.  The [0..n] cardinality indicates that any number
 of QoSPolicyPoliceAction objects may be given the same action to be
 executed as the exceeding action.

7.3.2. The Reference "Dependent"

 This property is inherited from the Dependency association, and is
 overridden to become an object reference to a PolicyAction object.
 This represents a specific policy action that is used by a given
 QoSPolicyPoliceAction.  The [1..1] cardinality means that a exactly
 one policy action can be used as the "exceed" action by a
 QoSPolicyPoliceAction.  To execute more than one conforming action,
 use the PolicyCompoundAction class to model the exceeding action.

7.4. The Association "PolicyViolateAction"

 This association links a policing action with an object defining an
 action to be applied to traffic violating the associated traffic
 profile.  The class definition for this association is as follows:
 NAME              PolicyViolateAction
 DESCRIPTION       A class representing the association between
                   a policing action and the action that should be
                   applied to traffic violating an associated traffic
                   profile.
 DERIVED FROM      Dependency (see [PCIM])
 ABSTRACT          FALSE
 PROPERTIES        Antecedent[ref QoSPolicePoliceAction[0..n]]
                   Dependent[ref PolicyAction [1..1]]

7.4.1. The Reference "Antecedent"

 This property is inherited from the Dependency association.  Its type
 is overridden to become an object reference to a
 QoSPolicyPoliceAction object.  This represents the "independent" part
 of the association.  The [0..n] cardinality indicates that any number
 of QoSPolicyPoliceAction objects may be given the same action to be
 executed as the violating action.

Snir, et al. Standards Track [Page 46] RFC 3644 Policy QoS Information Model November 2003

7.4.2. The Reference "Dependent"

 This property is inherited from the Dependency association, and is
 overridden to become an object reference to a PolicyAction object.
 This represents a specific policy action that is used by a given
 QoSPolicyPoliceAction.  The [1..1] cardinality means that exactly one
 policy action can be used as the "violate" action by a
 QoSPolicyPoliceAction.  To execute more than one violating action,
 use the PolicyCompoundAction class to model the conforming action.

7.5. The Aggregation "QoSPolicyRSVPVariableInRSVPSimplePolicyAction"

 A simple RSVP policy action is represented as a pair {variable,
 value}. This aggregation provides the linkage between a
 QoSPolicyRSVPSimpleAction instance and a single
 QoSPolicyRSVPVariable.  The aggregation
 PolicyValueInSimplePolicyAction links the QoSPolicyRSVPSimpleAction
 to a single PolicyValue.
 The class definition for this aggregation is as follows:
 NAME             QoSPolicyRSVPVariableInRSVPSimplePolicyAction
 DERIVED FROM     PolicyVariableInSimplePolicyAction
 ABSTRACT         FALSE
 PROPERTIES       GroupComponent[ref QoSPolicyRSVPSimpleAction
                    [0..n]]
                  PartComponent[ref QoSPolicyRSVPVariable [1..1] ]

7.5.1. The Reference "GroupComponent"

 The reference property "GroupComponent" is inherited from
 PolicyComponent, and overridden to become an object reference to a
 QoSPolicyRSVPSimpleAction that contains exactly one
 QoSPolicyRSVPVariable.  Note that for any single instance of the
 aggregation class QoSPolicyRSVPVariableInRSVPSimplePolicyAction, this
 property is single-valued.  The [0..n] cardinality indicates that
 there may be 0, 1, or more QoSPolicyRSVPSimpleAction objects that
 contain any given RSVP variable object.

7.5.2. The Reference "PartComponent"

 The reference property "PartComponent" is inherited from
 PolicyComponent, and overridden to become an object reference to a
 QoSPolicyRSVPVariable that is defined within the scope of a
 QoSPolicyRSVPSimpleAction.  Note that for any single instance of the
 association class QoSPolicyRSVPVariableInRSVPSimplePolicyAction, this
 property (like all reference properties) is single-valued.  The

Snir, et al. Standards Track [Page 47] RFC 3644 Policy QoS Information Model November 2003

 [1..1] cardinality indicates that a
 QoSPolicyRSVPVariableInRSVPSimplePolicyAction must have exactly one
 RSVP variable defined within its scope in order to be meaningful.

8. Class Definitions: Inheritance Hierarchy

 The following sections define object classes that are specified by
 QPIM.

8.1. The Class QoSPolicyDiscardAction

 This class is used to specify that packets should be discarded.  This
 is the same as stating that packets should be denied forwarding.  The
 class definition is as follows:
 NAME           QoSPolicyDiscardAction
 DESCRIPTION    This action specifies that packets should be
                discarded.
 DERIVED FROM   PolicyAction (defined in [PCIM])
 ABSTRACT       FALSEFALSE
 PROPERTIES     None

8.2. The Class QoSPolicyAdmissionAction

 This class is the base class for performing admission decisions based
 on a comparison of a meter measuring the temporal behavior of a flow
 or a set of flow with a traffic profile.  The qpAdmissionScope
 property controls whether the comparison is done per flow or per
 class (of flows).  Only packets that conform to the traffic profile
 are admitted for further processing; other packets are discarded.
 The class definition is as follows:
 NAME           QoSPolicyAdmissionAction
 DESCRIPTION    This action controls admission decisions based on
                comparison of a meter to a traffic profile.
 DERIVED FROM   PolicyAction (defined in [PCIM])
 ABSTRACT       FALSEFALSE
 PROPERTIES     qpAdmissionScope

8.2.1. The Property qpAdmissionScope

 This attribute specifies whether the admission decision is done per
 flow or per the entire class of flows defined by the rule condition.
 If the scope is "flow", the actual or requested rate of each flow is
 compared against the traffic profile.  If the scope is set to
 "class", the aggregate actual or requested rate of all flows matching
 the rule condition is measured against the traffic profile.  The
 property is defined as follows:

Snir, et al. Standards Track [Page 48] RFC 3644 Policy QoS Information Model November 2003

 NAME         qpAdmissionScope
 DESCRIPTION  This property specifies whether the admission decision
              is done per flow or per the entire class of flows.
 SYNTAX       Integer
 VALUE        This is an enumerated integer.  A value of 0 specifies
              that admission is done on a per-flow basis, and a value
              of 1 specifies that admission is done on a per-class
              basis.

8.3. The Class QoSPolicyPoliceAction

 This is used for defining policing actions (i.e., those actions that
 restrict traffic based on a comparison with a traffic profile).
 Using the three associations QoSPolicyConformAction,
 QoSPolicyExceedAction and QoSPolicyViolateAction, it is possible to
 specify different actions to take based on whether the traffic is
 conforming, exceeding, or violating a traffic profile.  The traffic
 profile is specified in a subclass of the QoSPolicyTrfcProf class.
 The class definition is as follows:
 NAME         QoSPolicyPoliceAction
 DESCRIPTION  This action controls the operation of policers.  The
              rate of flows is measured against a traffic profile.
              The actions that need to be performed on conforming,
              exceeding and violating traffic are indicated using
              the conform, exceed and violate action associations.
 DERIVED FROM QoSPolicyAdmissionAction (defined in this document)
 ABSTRACT     FALSEFALSE
 PROPERTIES   None

8.4. The Class QoSPolicyShapeAction

 This class is used for defining shaping actions.  Shapers are used to
 delay some or all of the packets in a traffic stream in order to
 bring a particular traffic stream into compliance with a given
 traffic profile.  The traffic profile is specified in a subclass of
 the QoSPolicyTrfcProf class.  The class definition is as follows:
 NAME         QoSPolicyShapeAction
 DESCRIPTION  This action indicate that traffic should be shaped to be
              conforming with a traffic profile.
 DERIVED FROM QoSPolicyAdmissionAction (defined in this document)
 ABSTRACT     FALSEFALSE
 PROPERTIES   None

Snir, et al. Standards Track [Page 49] RFC 3644 Policy QoS Information Model November 2003

8.5. The Class QoSPolicyRSVPAdmissionAction

 This class determines whether to accept or reject a given RSVP
 request by comparing the RSVP request's TSPEC or RSPEC parameters
 against the associated traffic profile and/or by enforcing the pre-
 set maximum sessions limit.  The traffic profile is specified in the
 QoSPolicyIntServTrfcProf class.  This class inherits the
 qpAdmissionScope property from its superclass.  This property
 specifies whether admission should be done on a per-flow or per-class
 basis.  If the traffic profile is not larger than or equal to the
 requested reservation, or to the sum of the admitted reservation
 merged with the requested reservation, the result is a deny decision.
 If no traffic profile is specified, the assumption is that all
 traffic can be admitted.
 The class definition is as follows:
 NAME         QoSPolicyRSVPAdmissionAction
 DESCRIPTION  This action controls the admission of RSVP requests.
              Depending on the scope, either a single RSVP request or
              the total admitted RSVP requests matching the conditions
              are compared against a traffic profile.
 DERIVED FROM QoSPolicyAdmissionAction (defined in this document)
 ABSTRACT     FALSEFALSE
 PROPERTIES   qpRSVPWarnOnly, qpRSVPMaxSessions

8.5.1. The Property qpRSVPWarnOnly

 This property is applicable when fulfilling ("admitting") an RSVP
 request would violate the policer (traffic profile) limits or when
 the maximum number session would be exceeded (or both).
 When this property is set to TRUE, the RSVP request is admitted in
 spite of the violation, but an RSVP error message carrying a warning
 is sent to the originator (sender or receiver).  When set to FALSE,
 the request would be denied and an error message would be sent back
 to the originator.  So the meaning of the qpWarnOnly flag is: Based
 on property's value (TRUE or FALSE), determine whether to admit but
 warn the originator that the request is in violation or to deny the
 request altogether (and send back an error).
 Specifically, a PATHERR (in response to a Path message) or a RESVERR
 (in response of a RESV message) will be sent.  This follows the COPS
 for RSVP send error flag in the Decision Flags object.  This property
 is defined as follows:

Snir, et al. Standards Track [Page 50] RFC 3644 Policy QoS Information Model November 2003

 NAME      qpRSVPWarnOnly
 SYNTAX    Boolean
 Default   FALSE
 VALUE     The value TRUE means that the request should be admitted
           AND an RSVP warning message should be sent to the
           originator.  The value of FALSE means that the request
           should be not admitted and an appropriate error message
           should be sent back to the originator of the request.

8.5.2. The Property qpRSVPMaxSessions

 This attribute is used to limit the total number of RSVP requests
 admitted for the specified class of traffic.  For this property to be
 meaningful, the qpAdmissionScope property must be set to class.  The
 definition of this property is as follows:
 NAME     qpRSVPMaxSessions
 SYNTAX   Integer
 VALUE    Must be greater than 0.

8.6. The Class QoSPolicyPHBAction

 This class is a base class that is used to define the per-hop
 behavior that is to be assigned to behavior aggregates.  It defines a
 common property, qpMaxPacketSize, for use by its subclasses
 (QoSPolicyBandwidthAction and QoSPolicyCongestionControlAction).  The
 class definition is as follows:
 NAME           QoSPolicyPHBAction
 DESCRIPTION    This action controls the Per-Hop-Behavior provided to
                behavior aggregates.
 DERIVED FROM   PolicyAction  (defined in [PCIM])
 ABSTRACT       TRUE
 PROPERTIES     qpMaxPacketSize

8.6.1. The Property qpMaxPacketSize

 This property specifies the maximum packet size in bytes, of packets
 in the designated flow.  This attribute is used in translation of
 QPIM attributes to QoS mechanisms used within a PEP.  For example,
 queue length may be measured in bytes, while the minimum number of
 packets that should be kept in a PEP is defined within QPIM in number
 of packets.  This property is defined as follows:
 NAME       qpMaxPacketSize
 SYNTAX     Integer
 Value      Must be greater than 0

Snir, et al. Standards Track [Page 51] RFC 3644 Policy QoS Information Model November 2003

8.7. The Class QoSPolicyBandwidthAction

 This class is used to control the bandwidth, delay, and forwarding
 behavior of a PHB.  Its class definition is as follows:
 NAME           QoSPolicyBandwidthAction
 DESCRIPTION    This action controls the bandwidth, delay, and
                forwarding characteristics of the PHB.
 DERIVED FROM   QoSPolicyPBHAction (defined in this document)
 ABSTRACT       FALSE
 PROPERTIES     qpForwardingPriority, qpBandwidthUnits,
                qpMinBandwdith, qpMaxBandwidth, qpMaxDelay,
                qpMaxJitter, qpFairness

8.7.1. The Property qpForwardingPriority

 This property defines the forwarding priority for this set of flows.
 A non-zero value indicates that preemptive forwarding is required.
 Higher values represent higher forwarding priority.  This property is
 defined as follows:
 NAME        qpForwardingPriority
 SYNTAX      Integer
 VALUE       Must be non-negative.  The value 0 means that preemptive
             forwarding is not required.  A positive value indicates
             the priority that is to be assigned for this (set of)
             flow(s).  Larger values represent higher priorities.

8.7.2. The Property qpBandwidthUnits

 This property defines the units that the properties qpMinBandwidth
 and qpMaxBandwidth have.  Bandwidth can either be defined in bits/sec
 or as a percentage of the available bandwidth or scheduler resources.
 This property is defined as follows:
 NAME        qpBandwidthUnits
 SYNTAX      Integer
 VALUE       Two values are possible.  The value of 0 is used to
             specify units of bits/sec, while the value of 1 is used
             to specify units as a percentage of the available
             bandwidth.  If this property indicates that the bandwidth
             units are percentages, then each of the bandwidth
             properties expresses a whole-number percentage, and hence
             its maximum value is 100.

Snir, et al. Standards Track [Page 52] RFC 3644 Policy QoS Information Model November 2003

8.7.3. The Property qpMinBandwidth

 This property defines the minimum bandwidth that should be reserved
 for this class of traffic.  Both relative (i.e., a percentage of the
 bandwidth) and absolute (i.e., bits/second) values can be specified
 according to the value of the qpBandwidthUnits property.  This
 property is defined as follows:
 NAME        qpMinBandwidth
 SYNTAX      Integer
 VALUE       The value must be greater than 0.  If the property
             qpMaxBandwidth is defined, then the value of
             qpMinBandwidth must be less than or equal to the value of
             qpMaxBandwidth.

8.7.4. The Property qpMaxBandwidth

 This property defines the maximum bandwidth that should be allocated
 to this class of traffic.  Both relative (i.e., a percentage of the
 bandwidth)and absolute (i.e., bits/second) values can be specified
 according to the value of the qpBandwidthUnits property.  This
 property is defined as follows:
 NAME        qpMaxBandwidth
 SYNTAX      Integer
 VALUE       The value must be greater than 0.  If the property
             qpMaxBandwidth is defined, then the value of
             qpMinBandwidth must be less than or equal to the value of
             qpMaxBandwidth.

8.7.5. The Property qpMaxDelay

 This property defines the maximal per-hop delay that traffic of this
 class should experience while being forwarded through this hop.  The
 maximum delay is measured in microseconds.  This property is defined
 as follows:
 NAME        qpMaxDelay
 SYNTAX      Integer (microseconds)
 VALUE       The value must be greater than 0.

8.7.6. The Property qpMaxJitter

 This property defines the maximal per-hop delay variance that traffic
 of this class should experience while being forwarded through this
 hop. The maximum jitter is measured in microseconds.  This property
 is defined as follows:

Snir, et al. Standards Track [Page 53] RFC 3644 Policy QoS Information Model November 2003

 NAME        qpMaxJitter
 SYNTAX      Integer (microseconds)
 VALUE       The value must be greater than 0.

8.7.7. The Property qpFairness

 This property defines whether fair queuing is required for this class
 of traffic.  This property is defined as follows:
 NAME        qpFairness
 SYNTAX      Boolean
 VALUE       The value of FALSE means that fair queuing is not
             required for this class of traffic, while the value of
             TRUE means that fair queuing is required for this class
             of traffic.

8.8. The Class QoSPolicyCongestionControlAction

 This class is used to control the characteristics of the congestion
 control algorithm being used.  The class definition is as follows:
 NAME         QoSPolicyCongestionControlAction
 DESCRIPTION  This action control congestion control characteristics
              of the PHB.
 DERIVED FROM QoSPolicyPBHAction (defined in this document)
 ABSTRACT     FALSE
 PROPERTIES   qpQueueSizeUnits, qpQueueSize, qpDropMethod,
              qpDropThresholdUnits, qpDropMinThresholdValue,
              qpDropMaxThresholdValue

8.8.1. The property qpQueueSizeUnits

 This property specifies the units in which the qpQueueSize attribute
 is measured.  The queue size is measured either in number of packets
 or in units of time.  The time interval specifies the time needed to
 transmit all packets within the queue if the link speed is dedicated
 entirely to transmission of packets within this queue.  The property
 definition is:
 NAME        qpQueueSizeUnits
 SYNTAX      Integer
 VALUE       This property can have two values.  If the value is set
             to 0, then the unit of measurement is number of packets.
             If the value is set to 1, then the unit of measurement is
             milliseconds.

Snir, et al. Standards Track [Page 54] RFC 3644 Policy QoS Information Model November 2003

8.8.2. The Property qpQueueSize

 This property specifies the maximum queue size in packets or in
 milliseconds, depending on the value of the qpQueueSizeUnits (0
 specifies packets, and 1 specifies milliseconds).  This property is
 defined as follows:
 NAME        qpQueueSize
 SYNTAX      Integer
 VALUE       This value must be greater than 0.

8.8.3. The Property qpDropMethod

 This property specifies the congestion control drop algorithm that
 should be used for this type of traffic.  This property is defined as
 follows:
 NAME        qpDropMethod
 SYNTAX      Integer
 VALUES      Three values are currently defined.  The value 0
             specifies a random drop algorithm, the value 1 specifies
             a tail drop algorithm, and the value 2 specifies a head
             drop algorithm.

8.8.4. The Property qpDropThresholdUnits

 This property specifies the units in which the two properties
 qpDropMinThresholdValue and qpDropMaxThresholdValue are measured.
 Thresholds can be measured either in packets or as a percentage of
 the available queue sizes.  This property is defined as follows:
 NAME        qpDropThresholdUnits
 SYNTAX      Integer
 VALUES      Three values are defined.  The value 0 defines the units
             as number of packets, the value 1 defines the units as a
             percentage of the queue size and the value 2 defines the
             units in milliseconds.  If this property indicates that
             the threshold units are percentages, then each of the
             threshold properties expresses a whole-number percentage,
             and hence its maximum value is 100.

8.8.5. The Property qpDropMinThresholdValue

 This property specifies the minimum number of queuing and buffer
 resources that should be reserved for this class of flows.  The
 threshold can be specified as either relative (i.e., a percentage) or
 absolute (i.e., number of packets or millisecond) value according to
 the value of the qpDropThresholdUnits property.  If this property

Snir, et al. Standards Track [Page 55] RFC 3644 Policy QoS Information Model November 2003

 specifies a value of 5 packets, then enough buffer and queuing
 resources should be reserved to hold 5 packets before running the
 specified congestion control drop algorithm.  This property is
 defined as follows:
 NAME        qpDropMinThresholdValue
 SYNTAX      Integer
 VALUE       This value must be greater than or equal to 0.  If the
             property qpDropMaxThresholdValue is defined, then the
             value of the qpDropMinThresholdValue property must be
             less than or equal to the value of the
             qpDropMaxThresholdValue property.

8.8.6. The Property qpDropMaxThresholdValue

 This property specifies the maximum number of queuing and buffer
 resources that should be reserved for this class of flows.  The
 threshold can be specified as either relative (i.e., a percentage) or
 absolute (i.e., number of packets or milliseconds) value according to
 the value of the qpDropThresholdUnits property.  Congestion Control
 droppers should not keep more packets than the value specified in
 this property.  Note, however, that some droppers may calculate queue
 occupancy averages, and therefore the actual maximum queue resources
 should be larger.  This property is defined as follows:
 NAME        qpDropMaxThresholdValue
 SYNTAX      Integer
 VALUE       This value must be greater than or equal to 0.  If the
             property qpDropMinThresholdValue is defined, then the
             value of the qpDropMinThresholdValue property must be
             less than or equal to the value of the
             qpDropMaxThresholdValue property.

8.9. Class QoSPolicyTrfcProf

 This is an abstract base class that models a traffic profile.
 Traffic profiles specify the maximum rate parameters used within
 admission decisions.  The association
 QoSPolicyTrfcProfInAdmissionAction binds the admission decision to
 the traffic profile.  The class definition is as follows:
 NAME          QoSPolicyTrfcProf
 DERIVED FROM  Policy (defined in [PCIM])
 ABSTRACT      TRUE
 PROPERTIES    None

Snir, et al. Standards Track [Page 56] RFC 3644 Policy QoS Information Model November 2003

8.10. Class QoSPolicyTokenBucketTrfcProf

 This class models a two- or three-level Token Bucket traffic profile.
 Additional profiles can be modeled by cascading multiple instances of
 this class (e.g., by connecting the output of one instance to the
 input of another instance).  This traffic profile carries the policer
 or shaper rate values to be enforced on a flow or a set of flows.
 The class definition is as follows:
 NAME          QoSPolicyTokenBucketTrfcProf
 DERIVED FROM  QoSPolicyTrfcProf (defined in this document)
 ABSTRACT      FALSE
 PROPERTIES    qpTBRate, qpTBNormalBurst, qpTBExcessBurst

8.10.1. The Property qpTBRate

 This is a non-negative integer that defines the token rate in
 kilobits per second.  A rate of zero means that all packets will be
 out of profile.  This property is defined as follows:
 NAME        qpTBRate
 SYNTAX      Integer
 VALUE       This value must be greater than to 0

8.10.2. The Property qpTBNormalBurst

 This property is an integer that defines the normal size of a burst
 measured in bytes.  This property is defined as follows:
 NAME        qpTBNormalBurst
 SYNTAX      Integer
 VALUE       This value must be greater than to 0

8.10.3. The Property qpTBExcessBurst

 This property is an integer that defines the excess burst size
 measured in bytes.  This property is defined as follows:
 NAME        qpTBExcessBurst
 SYNTAX      Integer
 VALUE       This value must be greater than or equal to
             qpTBNormalBurst

8.11. Class QoSPolicyIntServTrfcProf

 This class represents an IntServ traffic profile.  Values of IntServ
 traffic profiles are compared against Traffic specification (TSPEC)
 and QoS Reservation (FLOWSPEC) requests carried in RSVP requests.

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 The class definition is as follows:
 NAME          QoSPolicyIntServTrfcProf
 DERIVED FROM  QoSPolicyTrfcProf (defined in this document)
 ABSTRACT      FALSE
 PROPERTIES    qpISTokenRate, qpISPeakRate, qpISBucketSize,
               qpISResvRate, qpISResvSlack, qpISMinPolicedUnit,
               qpISMaxPktSize

8.11.1. The Property qpISTokenRate

 This property is a non-negative integer that defines the token rate
 parameter, measured in kilobits per second.  This property is defined
 as follows:
 NAME        qpISTokenRate
 SYNTAX      Integer
 VALUE       This value must be greater than or equal to 0

8.11.2. The Property qpISPeakRate

 This property is a non-negative integer that defines the peak rate
 parameter, measured in kilobits per second.  This property is defined
 as follows:
 NAME        qpISPeakRate
 SYNTAX      Integer
 VALUE       This value must be greater than or equal to 0

8.11.3. The Property qpISBucketSize

 This property is a non-negative integer that defines the token bucket
 size parameter, measured in bytes.  This property is defined as
 follows:
 NAME        qpISBucketSize
 SYNTAX      Integer
 VALUE       This value must be greater than or equal to 0

8.11.4. The Property qpISResvRate

 This property is a non-negative integer that defines the reservation
 rate (R-Spec) in the RSVP guaranteed service reservation.  It is
 measured in kilobits per second.  This property is defined as
 follows:

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 NAME        qpISResvRate
 SYNTAX      Integer
 VALUE       This value must be greater than or equal to 0

8.11.5. The Property qpISResvSlack

 This property is a non-negative integer that defines the RSVP slack
 term in the RSVP guaranteed service reservation.  It is measured in
 microseconds.  This property is defined as follows:
 NAME        qpISResvSlack
 SYNTAX      Integer
 VALUE       This value must be greater than or equal to 0

8.11.6. The Property qpISMinPolicedUnit

 This property is a non-negative integer that defines the minimum RSVP
 policed unit, measured in bytes.  This property is defined as
 follows:
 NAME        qpISMinPolicedUnit
 SYNTAX      Integer
 VALUE       This value must be greater than or equal to 0

8.11.7. The Property qpISMaxPktSize

 This property is a positive integer that defines the maximum allowed
 packet size for RSVP messages, measured in bytes.  This property is
 defined as follows:
 NAME        qpISMaxPktSize
 SYNTAX      Integer
 VALUE       This value must be a positive integer, denoting the
             number of bytes in the largest payload packet of an RSVP
             signaled flow or class.

8.12. The Class QoSPolicyAttributeValue

 This class can be used for representing an indirection in variable
 and value references either in a simple condition ("<x> match <y>")
 or a simple action ("<x> = <y>").  In both cases, <x> and <y> are
 known as the variable and the value of either the condition or
 action.  The value of the properties qpAttributeName and
 qpAttributeValueList are used to substitute <x> and <y> in the
 condition or action respectively.

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 The substitution is done as follows: The value of the property
 qpAttributeName is used to substitute <x> and the value of the
 property qpAttributeValueList is used to substitute <y>.
 Once the substitution is done, the condition can be evaluated and the
 action can be performed.
 For example, suppose we want to define a condition over a user name
 of the form "user == 'Smith'", using the QoSPolicyRSVPUserVariable
 class.  The user information in the RSVP message provides a DN.  The
 DN points to a user objects holding many attributes.  If the relevant
 attribute is "last name", we would use the QoSPolicyAttributeValue
 class with qpAttributeName = "Last Name", qpAttributeValueList =
 {"Smith"}.
 The class definition is as follows:
 NAME           QoSPolicyAttributeValue
 DERIVED FROM   PolicyValue (defined in [PCIMe])
 ABSTRACT       FALSE
 PROPERTIES     qpAttributeName, qpAttributeValueList

8.12.1. The Property qpAttributeName

 This property carries the name of the attribute that is to be used to
 substitute <x> in a simple condition or simple condition of the forms
 "<x> match <y>" or "<x> = <y>" respectively.  This property is
 defined as follows:
 NAME       qpAttributeName
 SYNTAX     String

8.12.2. The Property qpAttributeValueList

 This property carries a list of values that is to be used to
 substitute <y> in a simple condition or simple action of the forms
 "<x> match <y>" or "<x> = <y>" respectively.
 This property is defined as follows:
 NAME       qpAttributeValueList
 SYNTAX     String

8.13. The Class "QoSPolicyRSVPVariable"

 This is an abstract class that serves as the base class for all
 implicit variables that have to do with RSVP conditioning.  The class
 definition is as follows:

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 NAME           QoSPolicyRSVPVariable
 DESCRIPTION    An abstract base class used to build other classes
                that specify different attributes of an RSVP request
 DERIVED FROM   PolicyImplicitVariable (defined in [PCIMe])
 ABSTRACT       TRUE
 PROPERTIES     None

8.14. The Class "QoSPolicyRSVPSourceIPv4Variable"

 This is a concrete class that contains the source IPv4 address of the
 RSVP signaled flow, as defined in the RSVP PATH SENDER_TEMPLATE and
 RSVP RESV FILTER_SPEC [RSVP] objects.  The class definition is as
 follows:
 NAME           QoSPolicyRSVPSourceIPv4Variable
 DESCRIPTION    The source IPv4 address of the RSVP signaled flow, as
                defined in the RSVP PATH SENDER_TEMPLATE and RSVP RESV
                FILTER_SPEC [RSVP] objects.
                ALLOWED VALUE TYPES: PolicyIPv4AddrValue
 DERIVED FROM   QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT       FALSE
 PROPERTIES     None

8.15. The Class "QoSPolicyRSVPDestinationIPv4Variable"

 This is a concrete class that contains the destination IPv4 address
 of the RSVP signaled flow, as defined in the RSVP PATH
 SENDER_TEMPLATE and RSVP RESV FILTER_SPEC [RSVP] objects.  The class
 definition is as follows:
 NAME           QoSPolicyRSVPDestinationIPv4Variable
 DESCRIPTION    The destination IPv4 address of the RSVP signaled
                flow, as defined in the RSVP PATH and RESV SESSION
                [RSVP] objects.
                ALLOWED VALUE TYPES: PolicyIPv4AddrValue
 DERIVED FROM   QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT       FALSE
 PROPERTIES     None

Snir, et al. Standards Track [Page 61] RFC 3644 Policy QoS Information Model November 2003

8.16. The Class "QoSPolicyRSVPSourceIPv6Variable"

 This is a concrete class that contains the source IPv6 address of the
 RSVP signaled flow, as defined in the RSVP PATH SENDER_TEMPLATE and
 RSVP RESV FILTER_SPEC [RSVP] objects.  The class definition is as
 follows:
 NAME           QoSPolicyRSVPSourceIPv6Variable
 DESCRIPTION    The source IPv6 address of the RSVP signaled flow, as
                defined in the RSVP PATH SENDER_TEMPLATE and RSVP RESV
                FILTER_SPEC [RSVP] objects.
                ALLOWED VALUE TYPES: PolicyIPv6AddrValue
 DERIVED FROM   QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT       FALSE
 PROPERTIES     None

8.17. The Class "QoSPolicyRSVPDestinationIPv6Variable"

 This is a concrete class that contains the destination IPv6 address
 of the RSVP signaled flow, as defined in the RSVP PATH
 SENDER_TEMPLATE and RSVP RESV FILTER_SPEC [RSVP] objects.  The class
 definition is as follows:
 NAME           QoSPolicyRSVPDestinationIPv6Variable
 DESCRIPTION    The destination IPv6 address of the RSVP signaled
                flow, as defined in the RSVP PATH and RESV SESSION
                [RSVP] objects.
                ALLOWED VALUE TYPES: PolicyIPv6AddrValue
 DERIVED FROM   QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT       FALSE
 PROPERTIES     None

8.18. The Class "QoSPolicyRSVPSourcePortVariable"

 This class contains the source port of the RSVP signaled flow, as
 defined in the RSVP PATH SENDER_TEMPLATE and RSVP RESV FILTER_SPEC
 [RSVP] objects.  The class definition is as follows:
 NAME           QoSPolicyRSVPSourcePortVariable
 DESCRIPTION    The source port of the RSVP signaled flow, as defined
                in the RSVP PATH SENDER_TEMPLATE and RSVP RESV
                FILTER_SPEC [RSVP] objects.
                ALLOWED VALUE TYPES: PolicyIntegerValue (0..65535)

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 DERIVED FROM   QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT       FALSE
 PROPERTIES     None

8.19. The Class "QoSPolicyRSVPDestinationPortVariable"

 This is a concrete class that contains the destination port of the
 RSVP signaled flow, as defined in the RSVP PATH SENDER_TEMPLATE and
 RSVP RESV FILTER_SPEC [RSVP] objects.  The class definition is as
 follows:
 NAME           QoSPolicyRSVPDestinationPortVariable
 DESCRIPTION    The destination port of the RSVP signaled flow, as
                defined in the RSVP PATH and RESV SESSION [RSVP]
                objects.
                ALLOWED VALUE TYPES: PolicyIntegerValue (0..65535)
 DERIVED FROM   QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT       FALSE
 PROPERTIES     None

8.20. The Class "QoSPolicyRSVPIPProtocolVariable"

 This is a concrete class that contains the IP Protocol number of the
 RSVP signaled flow, as defined in the RSVP PATH and RESV SESSION
 [RSVP] objects.  The class definition is as follows:
 NAME           QoSPolicyRSVPIPProtocolVariable
 DESCRIPTION    The IP Protocol number of the RSVP signaled flow, as
                defined in the RSVP PATH and RESV SESSION [RSVP]
                objects.
                ALLOWED VALUE TYPES: PolicyIntegerValue
 DERIVED FROM   QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT       FALSE
 PROPERTIES     None

8.21. The Class "QoSPolicyRSVPIPVersionVariable"

 This is a concrete class that contains the IP Protocol version number
 of the RSVP signaled flow, as defined in the RSVP PATH and RESV
 SESSION [RSVP] objects.  The well-known version numbers are 4 and 6.
 This variable allows a policy definition of the type:
    "If IP version = IPv4 then ...".

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 The class definition is as follows:
 NAME           QoSPolicyRSVPIPVersionVariable
 DESCRIPTION    The IP version number of the IP Addresses carried the
                RSVP signaled flow, as defined in the RSVP PATH and
                RESV SESSION [RSVP] objects.
                ALLOWED VALUE TYPES: PolciIntegerValue
 DERIVED FROM   QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT       FALSE
 PROPERTIES     None

8.22. The Class "QoSPolicyRSVPDCLASSVariable"

 This is a concrete class that contains the DSCP value as defined in
 the RSVP DCLASS [DCLASS] object.  The class definition is as follows:
 NAME           QoSPolicyRSVPDCLASSVariable
 DESCRIPTION    The DSCP value as defined in the RSVP DCLASS [DCLASS]
                object.
                ALLOWED VALUE TYPES: PolicyIntegerValue,
                                     PolicyBitStringValue
 DERIVED FROM   QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT       FALSE
 PROPERTIES     None

8.23. The Class "QoSPolicyRSVPStyleVariable"

 This is a concrete class that contains the reservation style as
 defined in the RSVP STYLE object in the RESV message [RSVP].  The
 class definition is as follows:
 NAME           QoSPolicyRSVPStyleVariable
 DESCRIPTION    The reservation style as defined in the RSVP STYLE
                object in the RESV message [RSVP].
                ALLOWED VALUE TYPES:  PolicyBitStringValue,
                                      PolicyIntegerValue (Integer has
                                      an enumeration of
                                      { Fixed-Filter=1,
                                       Shared-Explicit=2,
                                       Wildcard-Filter=3}

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 DERIVED FROM   QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT       FALSE
 PROPERTIES     None

8.24. The Class "QoSPolicyIntServVariable"

 This is a concrete class that contains the Integrated Service
 requested in the RSVP Reservation message, as defined in the FLOWSPEC
 RSVP Object [RSVP].  The class definition is as follows:
 NAME           QoSPolicyRSVPIntServVariable
 DESCRIPTION    The integrated Service requested in the RSVP
                Reservation message, as defined in the FLOWSPEC RSVP
                Object [RSVP].
               ALLOWED VALUE TYPES: PolicyIntegerValue (An enumerated
                                    value of { CL=1 , GS=2, NULL=3}
 DERIVED FROM   QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT       FALSE
 PROPERTIES     None

8.25. The Class "QoSPolicyRSVPMessageTypeVariable"

 This is a concrete class that contains the RSVP message type, as
 defined in the RSVP message common header [RSVP] object.  The class
 definition is as follows:
 NAME          QoSPolicyRSVPMessageTypeVariable
 DESCRIPTION   The RSVP message type, as defined in the RSVP message
               common header [RSVP] object.
               ALLOWED VALUE TYPES: Integer (An enumerated value of
                                     {PATH=1 , PATHTEAR=2, RESV=3,
                                      RESVTEAR=4, RESVERR=5, CONF=6,
                                      PATHERR=7}
 DERIVED FROM  QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT      FALSE
 PROPERTIES    None

8.26. The Class "QoSPolicyRSVPPreemptionPriorityVariable"

 This is a concrete class that contains the RSVP reservation priority,
 as defined in [RFC3181] object.  The class definition is as follows:
 NAME          QoSPolicyRSVPPreemptionPriorityVariable
 DESCRIPTION   The RSVP reservation priority as defined in [RFC3181].

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               ALLOWED VALUE TYPES: PolicyIntegerValue
 DERIVED FROM  QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT      FALSE
 PROPERTIES    None

8.27. The Class "QoSPolicyRSVPPreemptionDefPriorityVariable"

 This is a concrete class that contains the RSVP reservation defending
 priority, as defined in [RFC3181] object.  The class definition is as
 follows:
 NAME          QoSPolicyRSVPPreemptionDefPriorityVariable
 DESCRIPTION   The RSVP preemption reservation defending priority as
               defined in [RFC3181].
               ALLOWED VALUE TYPES: PolicyIntegerValue
 DERIVED FROM  QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT      FALSE
 PROPERTIES    None

8.28. The Class "QoSPolicyRSVPUserVariable"

 This is a concrete class that contains the ID of the user that
 initiated the flow as defined in the User Locator string in the
 Identity Policy Object [RFC3182].  The class definition is as
 follows:
 NAME          QoSPolicyRSVPUserVariable
 DESCRIPTION   The ID of the user that initiated the flow as defined
               in the User Locator string in the Identity Policy
               Object [RFC3182].
               ALLOWED VALUE TYPES: QoSPolicyDNValue,
                                    PolicyStringValue,
                                    QoSPolicyAttributeValue
 DERIVED FROM  QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT      FALSE
 PROPERTIES    None

8.29. The Class "QoSPolicyRSVPApplicationVariable"

 This is a concrete class that contains the ID of the application that
 generated the flow as defined in the application locator string in
 the Application policy object [RFC2872].  The class definition is as
 follows:

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 NAME          QoSPolicyRSVPApplicationVariable
 DESCRIPTION   The ID of the application that generated the flow as
               defined in the application locator string in the
               Application policy object [RFC2872].
               ALLOWED VALUE TYPES: QoSPolicyDNValue,
                                    PolicyStringValue,
                                    QoSPolicyAttributeValue
 DERIVED FROM  QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT      FALSE
 PROPERTIES    None

8.30. The Class "QoSPolicyRSVPAuthMethodVariable"

 This is a concrete class that contains the type of authentication
 used in the Identity Policy Object [RFC3182].  The class definition
 is as follows:
 NAME          QoSPolicyRSVPAuthMethodVariable
 DESCRIPTION   The RSVP Authentication type used in the Identity
               Policy Object [RFC3182].
               ALLOWED VALUE TYPES: PolicyIntegerValue (An enumeration
                                    of { NONE=0, PLAIN-TEXT=1,
                                    DIGITAL-SIG = 2, KERBEROS_TKT=3,
                                    X509_V3_CERT=4, PGP_CERT=5}
 DERIVED FROM  QoSPolicyRSVPVariable (defined in this document)
 ABSTRACT      FALSE
 PROPERTIES    None

8.31. The Class QoSPolicyDNValue

 This class is used to represent a single or set of Distinguished Name
 [DNDEF] values, including wildcards.  A Distinguished Name is a name
 that can be used as a key to retrieve an object from a directory
 service. This value can be used in comparison to reference values
 carried in RSVP policy objects, as specified in [RFC3182].  The class
 definition is as follows:
 NAME           QoSPolicyDNValue
 DERIVED FROM   PolicyValue
 ABSTRACT       FALSE
 PROPERTIES     qpDNList

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8.31.1. The Property qpDNList

 This attribute provides an unordered list of strings, each
 representing a Distinguished Name (DN) with wildcards.  The format of
 a DN is defined in [DNDEF].  The asterisk character ("*") is used as
 wildcard for either a single attribute value or a wildcard for an
 RDN.  The order of RDNs is significant.  For example: A qpDNList
 attribute carrying the following value:
    "CN=*, OU=Sales, O=Widget Inc., *, C=US" matches:
    "CN=J. Smith, OU=Sales, O=Widget Inc, C=US"
 and also matches:
    "CN=J. Smith, OU=Sales, O=Widget Inc, L=CA, C=US".
 The attribute is defined as follows:
 NAME     qpDNList
 SYNTAX   List of Distinguished Names implemented as strings, each of
          which serves as a reference to another object.

8.32. The Class QoSPolicyRSVPSimpleAction

 This action controls the content of RSVP messages and the way RSVP
 requests are admitted.  Depending on the value of its
 qpRSVPActionType property, this action directly translates into
 either a COPS Replace Decision or a COPS Stateless Decision, or both
 as defined in COPS for RSVP.  Only variables that are subclasses of
 the QoSPolicyRSVPVariable are allowed to be associated with this
 action.  The property definition is as follows:
 NAME          QoSPolicyRSVPSimpleAction
 DESCRIPTION   This action controls the content of RSVP messages and
               the way RSVP requests are admitted.
 DERIVED FROM  SimplePolicyAction (defined in [PCIMe])
 ABSTRACT      FALSE
 PROPERTIES    qpRSVPActionType

8.32.1. The Property qpRSVPActionType

 This property is an enumerated integer denoting the type(s) of RSVP
 action.  The value 'REPLACE' denotes a COPS Replace Decision action.
 The value 'STATELESS' denotes a COPS Stateless Decision action.  The
 value REPLACEANDSTATELESS denotes both decision actions.  Refer to
 [RFC2749] for details.

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 NAME          qpRSVPActionType
 DESCRIPTION   This property specifies whether the action type is for
               COPS Replace, Stateless, or both types of decisions.
 SYNTAX        Integer
 VALUE         This is an enumerated integer.  A value of 0 specifies
               a COPS Replace decision.  A value of 1 specifies a COPS
               Stateless Decision.  A value of 2 specifies both COPS
               Replace and COPS Stateless decisions.

9. Intellectual Property Rights Statement

 The IETF takes no position regarding the validity or scope of any
 intellectual property or other rights that might be claimed to
 pertain to the implementation or use of the technology described in
 this document or the extent to which any license under such rights
 might or might not be available; neither does it represent that it
 has made any effort to identify any such rights.  Information on the
 IETF's procedures with respect to rights in standards-track and
 standards-related documentation can be found in BCP-11.
 Copies of claims of rights made available for publication and any
 assurances of licenses to be made available, or the result of an
 attempt made to obtain a general license or permission for the use of
 such proprietary rights by implementers or users of this
 specification can be obtained from the IETF Secretariat.
 The IETF invites any interested party to bring to its attention any
 copyrights, patents or patent applications, or other proprietary
 rights which may cover technology that may be required to practice
 this standard.  Please address the information to the IETF Executive
 Director.

10. Acknowledgements

 The authors wish to thank the input of the participants of the Policy
 Framework working group, and especially the combined group of the
 PCIMe coauthors, Lee Rafalow, Andrea Westerinen, Ritu Chadha and
 Marcus Brunner.  In addition, we'd like to acknowledge the valuable
 contribution from Ed Ellesson, Joel Halpern and Mircea Pana.  Thank
 you all for your comments, critique, ideas and general contribution.

11. Security Considerations

 The Policy Core Information Model [PCIM] describes the general
 security considerations related to the general core policy model.
 The extensions defined in this document do not introduce any
 additional considerations related to security.

Snir, et al. Standards Track [Page 69] RFC 3644 Policy QoS Information Model November 2003

12. References

12.1. Normative References

 [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
            Requirement Levels", BCP 14, RFC 2119, March 1997.
 [PCIM]     Moore, B., Ellesson, E., Strassner, J. and A. Westerinen,
            "Policy Core Information Model -- Version 1
            Specification", RFC 3060, February 2001.
 [PCIMe]    Moore, B., Ed., "Policy Core Information Model
            Extensions", RFC 3460, January 2003.

12.2. Informative References

 [TERMS]    Westerinen, A., Schnizlein, J., Strassner, J., Scherling,
            M., Quinn, B., Herzog, S., Huynh, A., Carlson, M., Perry,
            J. and M. Waldbusser, "Terminology for Policy-based
            Management", RFC 3198, November 2001.
 [DIFFSERV] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.
            and W. Weiss, "An Architecture for Differentiated
            Services", RFC 2475, December 1998.
 [INTSERV]  Braden, R., Clark, D. and S. Shenker, "Integrated Services
            in the Internet Architecture: an Overview", RFC 1633, June
            1994.
 [RSVP]     Braden, R., Ed., Zhang, L., Berson, S.,  Herzog, S. and S.
            Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
            Functional Specification", RFC 2205, September 1997.
 [RFC2749]  Herzog, S., Ed., Boyle, J., Cohen, R., Durham, D., Rajan,
            R. and A. Sastry, "COPS usage for RSVP", RFC 2749, January
            2000.
 [RFC3181]  Herzog, S., "Signaled Preemption Priority Policy Element",
            RFC 3181, October 2001.
 [DIFF-MIB] Baker, F., Chan, K. and A. Smith, "Management Information
            Base for the Differentiated Services Architecture", RFC
            3289, May 2002.
 [AF]       Heinanen, J., Baker, F., Weiss, W. and J. Wroclawski,
            "Assured Forwarding PHB Group", RFC 2597, June 1999.

Snir, et al. Standards Track [Page 70] RFC 3644 Policy QoS Information Model November 2003

 [CL]       Wroclawski, J., "Specification of the Controlled-Load
            Network Element Service", RFC 2211, September 1997.
 [RSVP-IS]  Wroclawski, J., "The Use of RSVP with IETF Integrated
            Services", RFC 2210, September 1997.
 [GS]       Shenker, S., Partridge, C. and R. Guerin, "Specification
            of the Guaranteed Quality of Service", RFC 2212, September
            1997.
 [DCLASS]   Bernet, Y., "Format of the RSVP DCLASS Object", RFC 2996,
            November 2000.
 [RFC3182]  Yadav, S., Yavatkar, R., Pabbati, R., Ford, P., Moore, T.,
            Herzog, S. and R. Hess, "Identity Representation for
            RSVP", RFC 3182, October 2001.
 [RFC2872]  Bernet, Y. and R. Pabbati, "Application and Sub
            Application Identity Policy Element for Use with RSVP",
            RFC 2872, June 2000.
 [DNDEF]    Wahl, M., Kille, S. and T. Howes, "Lightweight Directory
            Access Protocol (v3): UTF-8 String Representation of
            Distinguished Names", RFC 2253, December 1997.

Snir, et al. Standards Track [Page 71] RFC 3644 Policy QoS Information Model November 2003

13. Authors' Addresses

 Yoram Ramberg
 Cisco Systems
 4 Maskit Street
 Herzliya Pituach, Israel  46766
 Phone:  +972-9-970-0081
 Fax:    +972-9-970-0219
 EMail:  yramberg@cisco.com
 Yoram Snir
 Cisco Systems
 300 East Tasman Drive
 San Jose, CA 95134
 Phone:  +1 408-853-4053
 Fax:    +1 408 526-7864
 EMail:  ysnir@cisco.com
 John Strassner
 Intelliden Corporation
 90 South Cascade Avenue
 Colorado Springs, Colorado  80903
 Phone:  +1-719-785-0648
 Fax:    +1-719-785-0644
 EMail: john.strassner@intelliden.com
 Ron Cohen
 Ntear LLC
 Phone: +972-8-9402586
 Fax:   +972-9-9717798
 EMail: ronc@lyciumnetworks.com
 Bob Moore
 IBM Corporation
 P. O. Box 12195, BRQA/501/G206
 3039 Cornwallis Rd.
 Research Triangle Park, NC 27709-2195
 Phone:   +1 919-254-4436
 Fax:     +1 919-254-6243
 EMail: remoore@us.ibm.com

Snir, et al. Standards Track [Page 72] RFC 3644 Policy QoS Information Model November 2003

14. Full Copyright Statement

 Copyright (C) The Internet Society (2003).  All Rights Reserved.
 This document and translations of it may be copied and furnished to
 others, and derivative works that comment on or otherwise explain it
 or assist in its implementation may be prepared, copied, published
 and distributed, in whole or in part, without restriction of any
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 included on all such copies and derivative works.  However, this
 document itself may not be modified in any way, such as by removing
 the copyright notice or references to the Internet Society or other
 Internet organizations, except as needed for the purpose of
 developing Internet standards in which case the procedures for
 copyrights defined in the Internet Standards process must be
 followed, or as required to translate it into languages other than
 English.
 The limited permissions granted above are perpetual and will not be
 revoked by the Internet Society or its successors or assignees.
 This document and the information contained herein is provided on an
 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

 Funding for the RFC Editor function is currently provided by the
 Internet Society.

Snir, et al. Standards Track [Page 73]

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