Intelliden Corporation
B. Moore
IBM Corporation
R. Moats
Lemur Networks, Inc.
E. Ellesson
February 2004
Policy Core Lightweight Directory Access Protocol (LDAP) Schema
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 © The Internet Society (2004). All Rights Reserved.
Abstract
-
This document defines a mapping of the Policy Core Information Model to a form that can be implemented in a directory that uses Lightweight Directory Access Protocol (LDAP) as its access protocol. This model defines two hierarchies of object classes: structural classes representing information for representing and controlling policy data as specified in RFC 3060, and relationship classes that indicate how instances of the structural classes are related to each other. Classes are also added to the LDAP schema to improve the performance of a client's interactions with an LDAP server when the client is retrieving large amounts of policy-related information. These classes exist only to optimize LDAP retrievals: there are no classes in the information model that correspond to them.
Table of Contents
-
1. Introduction ................................................. 2 2. The Policy Core Information Model ............................ 4 3. Inheritance Hierarchy for the PCLS ........................... 5 4. General Discussion of Mapping the Information Model to LDAP .. 6 4.1. Summary of Class and Association Mappings .............. 7 4.2. Usage of DIT Content and Structure Rules and Name Forms. 9 4.3. Naming Attributes in the PCLS .......................... 10 4.4. Rule-Specific and Reusable Conditions and Actions ...... 11 4.5. Location and Retrieval of Policy Objects in the Directory .............................................. 16 4.5.1. Aliases and Other DIT-Optimization Techniques .. 19 5. Class Definitions ............................................ 19 5.1. The Abstract Class "pcimPolicy" ........................ 21 5.2. The Three Policy Group Classes ......................... 22 5.3. The Three Policy Rule Classes .......................... 23 5.4. The Class pcimRuleConditionAssociation ................. 30 5.5. The Class pcimRuleValidityAssociation .................. 32 5.6. The Class pcimRuleActionAssociation .................... 34 5.7. The Auxiliary Class pcimConditionAuxClass .............. 36 5.8. The Auxiliary Class pcimTPCAuxClass .................... 36 5.9. The Auxiliary Class pcimConditionVendorAuxClass ........ 40 5.10. The Auxiliary Class pcimActionAuxClass ................. 41 5.11. The Auxiliary Class pcimActionVendorAuxClass ........... 42 5.12. The Class pcimPolicyInstance ........................... 43 5.13. The Auxiliary Class pcimElementAuxClass ................ 44 5.14. The Three Policy Repository Classes .................... 45 5.15. The Auxiliary Class pcimSubtreesPtrAuxClass ............ 46 5.16. The Auxiliary Class pcimGroupContainmentAuxClass ....... 48 5.17. The Auxiliary Class pcimRuleContainmentAuxClass ........ 49 6. Extending the Classes Defined in This Document ............... 50 6.1. Subclassing pcimConditionAuxClass and pcimActionAuxClass 50 6.2. Using the Vendor Policy Attributes ..................... 50 6.3. Using Time Validity Periods ............................ 51 7. Security Considerations ...................................... 51 8. IANA Considerations .......................................... 53 8.1. Object Identifiers ..................................... 53 8.2. Object Identifier Descriptors .......................... 53 9. Acknowledgments .............................................. 56 10. Appendix: Constructing the Value of orderedCIMKeys .......... 57 11. References ................................................... 58 11.1. Normative References ................................... 58 11.2. Informative References ................................. 59 12. Authors' Addresses ........................................... 60 13. Full Copyright Statement ..................................... 61
1. Introduction
-
This document takes as its starting point the object-oriented information model for representing information for representing and controlling policy data as specified in [1]. Lightweight Directory Access Protocol (LDAP) [2] implementers, please note that the use of the term "policy" in this document does not refer to the use of the term "policy" as defined in X.501 [4]. Rather, the use of the term "policy" throughout this document is defined as follows:
-
Policy is defined as a set of rules to administer, manage, and control access to network resources.
This work is currently under joint development in the IETF's Policy Framework working group and in the Policy working group of the Distributed Management Task Force (DMTF). This model defines two hierarchies of object classes: structural classes representing policy information and control of policies, and relationship classes that indicate how instances of the structural classes are related to each other. In general, both of these class hierarchies will need to be mapped to a particular data store.
This document defines the mapping of these information model classes to a directory that uses LDAP as its access protocol. Two types of mappings are involved:
-
- For the structural classes in the information model, the mapping is basically one-for-one: information model classes map to LDAP classes, information model properties map to LDAP attributes.
- For the relationship classes in the information model, different mappings are possible. In this document, the Policy Core Information Model's (PCIM's) relationship classes and their properties are mapped in three ways: to LDAP auxiliary classes, to attributes representing distinguished name (DN) references, and to superior-subordinate relationships in the Directory Information Tree (DIT).
Implementations that use an LDAP directory as their policy repository and want to implement policy information according to RFC 3060 [1] SHALL use the LDAP schema defined in this document, or a schema that subclasses from the schema defined in this document. The use of the information model defined in reference [1] as the starting point enables the inheritance and the relationship class hierarchies to be extensible, such that other types of policy repositories, such as relational databases, can also use this information.
This document fits into the overall framework for representing, deploying, and managing policies being developed by the Policy Framework Working Group.
The LDAP schema described in this document uses the prefix "pcim" to identify its classes and attributes. It consists of ten very general classes: pcimPolicy (an abstract class), three policy group classes (pcimGroup, pcimGroupAuxClass, and pcimGroupInstance), three policy rule classes (pcimRule, pcimRuleAuxClass, and pcimRuleInstance), and three special auxiliary classes (pcimConditionAuxClass, pcimTPCAuxClass, and pcimActionAuxClass). (Note that the PolicyTimePeriodCondition auxiliary class defined in [1] would normally have been named pcimTimePeriodConditionAuxClass, but this name is too long for some directories. Therefore, we have abbreviated this name to be pcimTPCAuxClass).
The mapping for the PCIM classes pcimGroup and pcimRule is designed to be as flexible as possible. Three classes are defined for these two PCIM classes. First, an abstract superclass is defined that contains all required properties of each PCIM class. Then, both an auxiliary class as well as a structural class are derived from the abstract superclass. This provides maximum flexibility for the developer.
The schema also contains two less general classes: pcimConditionVendorAuxClass and pcimActionVendorAuxClass. To achieve the mapping of the information model's relationships, the schema also contains two auxiliary classes: pcimGroupContainmentAuxClass and pcimRuleContainmentAuxClass. Capturing the distinction between rule-specific and reusable policy conditions and policy actions introduces seven other classes: pcimRuleConditionAssociation, pcimRuleValidityAssociation, pcimRuleActionAssociation, pcimPolicyInstance, and three policy repository classes (pcimRepository, pcimRepositoryAuxClass, and pcimRepositoryInstance). Finally, the schema includes two classes (pcimSubtreesPtrAuxClass and pcimElementAuxClass) for optimizing LDAP retrievals. In all, the schema contains 23 classes.
Within the context of this document, the term "PCLS" (Policy Core LDAP Schema) is used to refer to the LDAP class definitions that this document contains. The term "PCIM" refers to classes defined in [1].
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [10].
-
2. The Policy Core Information Model
-
This document contains an LDAP schema representing the classes defined in the companion document "Policy Core Information Model -- Version 1 Specification" [1]. Other documents may subsequently be produced, with mappings of this same PCIM to other storage technologies. Since the detailed semantics of the PCIM classes appear only in [1], that document is a prerequisite for reading and understanding this document.
3. Inheritance Hierarchy for the PCLS
-
The following diagram illustrates the class hierarchy for the LDAP Classes defined in this document:
-
top
| +--dlm1ManagedElement (abstract) | | | +--pcimPolicy (abstract) | | | | | +--pcimGroup (abstract) | | | | | | | +--pcimGroupAuxClass (auxiliary) | | | | | | | +--pcimGroupInstance (structural) | | | | | +--pcimRule (abstract) | | | | | | | +--pcimRuleAuxClass (auxiliary) | | | | | | | +--pcimRuleInstance (structural) | | | | | +--pcimRuleConditionAssociation (structural) | | | | | +--pcimRuleValidityAssociation (structural) | | | | | +--pcimRuleActionAssociation (structural) | | | | | +--pcimPolicyInstance (structural) | | | | | +--pcimElementAuxClass (auxiliary) | | | +--dlm1ManagedSystemElement (abstract) | | | +--dlm1LogicalElement (abstract) | | | +--dlm1System (abstract) | | | +--dlm1AdminDomain (abstract) | | | +--pcimRepository (abstract) | | | +--pcimRepositoryAuxClass (auxiliary)-
top
| | | +--pcimRepositoryInstance | (structural) | +--pcimConditionAuxClass (auxiliary) | | | +---pcimTPCAuxClass (auxiliary) | | | +---pcimConditionVendorAuxClass (auxiliary) | +--pcimActionAuxClass (auxiliary) | | | +---pcimActionVendorAuxClass (auxiliary) | +--pcimSubtreesPtrAuxClass (auxiliary) | +--pcimGroupContainmentAuxClass (auxiliary) | +--pcimRuleContainmentAuxClass (auxiliary) -
Figure 1. LDAP Class Inheritance Hierarchy for the PCLS
4. General Discussion of Mapping the Information Model to LDAP
-
The classes described in Section 5 below contain certain optimizations for a directory that uses LDAP as its access protocol. One example of this is the use of auxiliary classes to represent some of the associations defined in the information model. Other data stores might need to implement these associations differently. A second example is the introduction of classes specifically designed to optimize retrieval of large amounts of policy-related data from a directory. This section discusses some general topics related to the mapping from the information model to LDAP.
The remainder of this section will discuss the following topics. Section 4.1 will discuss the strategy used in mapping the classes and associations defined in [1] to a form that can be represented in a directory that uses LDAP as its access protocol. Section 4.2 discusses DIT content and structure rules, as well as name forms. Section 4.3 describes the strategy used in defining naming attributes for the schema described in Section 5 of this document. Section 4.4 defines the strategy recommended for locating and retrieving PCIM-derived objects in the directory.
4.1. Summary of Class and Association Mappings
-
Fifteen of the classes in the PCLS come directly from the nine corresponding classes in the information model. Note that names of classes begin with an upper case character in the information model (although for CIM in particular, case is not significant in class and property names), but with a lower case character in LDAP. This is because although LDAP doesn't care, X.500 doesn't allow class names to begin with an uppercase character. Note also that the prefix "pcim" is used to identify these LDAP classes.
+---------------------------+-------------------------------+ | Information Model | LDAP Class(es) | +---------------------------+-------------------------------+ +---------------------------+-------------------------------+ | Policy | pcimPolicy | +---------------------------+-------------------------------+ | PolicyGroup | pcimGroup | | | pcimGroupAuxClass | | | pcimGroupInstance | +---------------------------+-------------------------------+ | PolicyRule | pcimRule | | | pcimRuleAuxClass | | | pcimRuleInstance | +---------------------------+-------------------------------+ | PolicyCondition | pcimConditionAuxClass | +---------------------------+-------------------------------+ | PolicyAction | pcimActionAuxClass | +---------------------------+-------------------------------+ | VendorPolicyCondition | pcimConditionVendorAuxClass | +---------------------------+-------------------------------+ | VendorPolicyAction | pcimActionVendorAuxClass | +---------------------------+-------------------------------+ | PolicyTimePeriodCondition | pcimTPCAuxClass | +---------------------------+-------------------------------+ | PolicyRepository | pcimRepository | | | pcimRepositoryAuxClass | | | pcimRepositoryInstance | +---------------------------+-------------------------------+
Figure 2. Mapping of Information Model Classes to LDAP
-
The associations in the information model map to attributes that reference DNs (Distinguished Names) or to Directory Information Tree (DIT) containment (i.e., superior-subordinate relationships) in LDAP. Two of the attributes that reference DNs appear in auxiliary classes, which allow each of them to represent several relationships from the information model.
+----------------------------------+----------------------------------+ | Information Model Association | LDAP Attribute / Class | +-----------------------------------+---------------------------------+ +-----------------------------------+---------------------------------+ | PolicyGroupInPolicyGroup | pcimGroupsAuxContainedSet in | | | pcimGroupContainmentAuxClass | +-----------------------------------+---------------------------------+ | PolicyRuleInPolicyGroup | pcimRulesAuxContainedSet in | | | pcimRuleContainmentAuxClass | +-----------------------------------+---------------------------------+ | PolicyConditionInPolicyRule | DIT containment or | | | pcimRuleConditionList in | | | pcimRule or | | | pcimConditionDN in | | | pcimRuleConditionAssociation | +-----------------------------------+---------------------------------+ | PolicyActionInPolicyRule | DIT containment or | | | pcimRuleActionList in | | | pcimRule or | | | pcimActionDN in | | | pcimRuleActionAssociation | +-----------------------------------+---------------------------------+ | PolicyRuleValidityPeriod | pcimRuleValidityPeriodList | | | in pcimRule or (if reusable) | | | referenced through the | | | pcimTimePeriodConditionDN in | | | pcimRuleValidityAssociation | +-----------------------------------+---------------------------------+ | PolicyConditionInPolicyRepository | DIT containment | +-----------------------------------+---------------------------------+ | PolicyActionInPolicyRepository | DIT containment | +-----------------------------------+---------------------------------+ | PolicyRepositoryInPolicyRepository| DIT containment | +-----------------------------------+---------------------------------+
-
-
Figure 3. Mapping of Information Model Associations to LDAP
Of the remaining classes in the PCLS, two (pcimElementAuxClass and pcimSubtreesPtrAuxClass) are included to make navigation through the DIT and retrieval of the entries found there more efficient. This topic is discussed below in Section 4.5.
The remaining four classes in the PCLS, pcimRuleConditionAssociation, pcimRuleValidityAssociation, pcimRuleActionAssociation, and pcimPolicyInstance, are all involved with the representation of policy conditions and policy actions in an LDAP directory. This topic is discussed below in Section 4.4.
-
4.2. Usage of DIT Content and Structure Rules and Name Forms
-
There are three powerful tools that can be used to help define schemata. The first, DIT content rules, is a way of defining the content of an entry for a structural object class. It can be used to specify the following characteristics of the entry:
- additional mandatory attributes that the entries are required to contain - additional optional attributes the entries are allowed to contain - the set of additional auxiliary object classes that these entries are allowed to be members of - any optional attributes from the structural and auxiliary object class definitions that the entries are required to precludeDIT content rules are NOT mandatory for any structural object class.
A DIT structure rule, together with a name form, controls the placement and naming of an entry within the scope of a subschema. Name forms define which attribute type(s) are required and are allowed to be used in forming the Relative Distinguished Names (RDNs) of entries. DIT structure rules specify which entries are allowed to be superior to other entries, and hence control the way that RDNs are added together to make DNs.
A name form specifies the following:
- the structural object class of the entries named by this name form - attributes that are required to be used in forming the RDNs of these entries - attributes that are allowed to be used in forming the RDNs of these entries - an object identifier to uniquely identify this name formNote that name forms can only be specified for structural object classes. However, every entry in the DIT must have a name form controlling it.
Unfortunately, current LDAP servers vary quite a lot in their support of these features. There are also three crucial implementation points that must be followed. First, X.500 use of structure rules requires that a structural object class with no superior structure rule be a subschema administrative point. This is exactly NOT what we want for policy information. Second, when an auxiliary class is subclassed, if a content rule exists for the structural class that the auxiliary class refers to, then that content rule needs to be augmented. Finally, most LDAP servers unfortunately do not support inheritance of structure and content rules.
Given these concerns, DIT structure and content rules have been removed from the PCLS. This is because, if included, they would be normative references and would require OIDs. However, we don't want to lose the insight gained in building the structure and content rules of the previous version of the schema. Therefore, we describe where such rules could be used in this schema, what they would control, and what their effect would be.
4.3. Naming Attributes in the PCLS
-
Instances in a directory are identified by distinguished names (DNs), which provide the same type of hierarchical organization that a file system provides in a computer system. A distinguished name is a sequence of RDNs. An RDN provides a unique identifier for an instance within the context of its immediate superior, in the same way that a filename provides a unique identifier for a file within the context of the folder in which it resides.
To preserve maximum naming flexibility for policy administrators, three optional (i.e., "MAY") naming attributes have been defined. They are:
-
- Each of the structural classes defined in this schema has its own unique ("MAY") naming attribute. Since the naming attributes are different, a policy administrator can, by using these attributes, guarantee that there will be no name collisions between instances of different classes, even if the same value is assigned to the instances' respective naming attributes.
- The LDAP attribute cn (corresponding to X.500's commonName) is included as a MAY attribute in the abstract class pcimPolicy, and thus by inheritance in all of its subclasses. In X.500, commonName typically functions as an RDN attribute, for naming instances of many classes (e.g., X.500's person class).
- A special attribute is provided for implementations that expect to map between native CIM and LDAP representations of policy information. This attribute, called orderedCimKeys, is defined in the class dlm1ManagedElement [6]. The value of this attribute is derived algorithmically from values that are already present in a CIM policy instance. The normative reference for this algorithm is contained in [6]. See the appendix of this document for a description of the algorithm.
Since any of these naming attributes MAY be used for naming an instance of a PCLS class, implementations MUST be able to accommodate instances named in any of these ways.
Note that it is recommended that two or more of these attributes SHOULD NOT be used together to form a multi-part RDN, since support for multi-part RDNs is limited among existing directory implementations.
-
4.4. Rule-Specific and Reusable Conditions and Actions
-
The PCIM [1] distinguishes between two types of policy conditions and policy actions: those associated with a single policy rule, and those that are reusable, in the sense that they may be associated with more than one policy rule. While there is no inherent functional difference between a rule-specific condition or action and a reusable one, there is both a usage, as well as, an implementation difference between them.
Defining a condition or action as reusable vs. rule-specific reflects a conscious decision on the part of the administrator in defining how they are used. In addition, there are variations that reflect implementing rule-specific vs. reusable policy conditions and actions and how they are treated in a policy repository. The major implementation differences between a rule-specific and a reusable condition or action are delineated below:
1. It is natural for a rule-specific condition or action to be removed from the policy repository at the same time the rule is. It is just the opposite for reusable conditions and actions. This is because the condition or action is conceptually attached to the rule in the rule-specific case, whereas it is referenced (e.g., pointed at) in the reusable case. The persistence of a pcimRepository instance is independent of the persistence of a pcimRule instance. 2. Access permissions for a rule-specific condition or action are usually identical to those for the rule itself. On the other hand, access permissions of reusable conditions and actions must be expressible without reference to a policy rule. 3. Rule-specific conditions and actions require fewer accesses, because the conditions and actions are "attached" to the rule. In contrast, reusable conditions and actions require more accesses, because each condition or action that is reusable requires a separate access. 4. Rule-specific conditions and actions are designed for use by a single rule. As the number of rules that use the same rule-specific condition increase, subtle problems are created (the most obvious being how to keep the rule-specific conditions and actions updated to reflect the same value). Reusable conditions and actions lend themselves for use by multiple independent rules. 5. Reusable conditions and actions offer an optimization when multiple rules are using the same condition or action. This is because the reusable condition or action only needs be updated once, and by virtue of DN reference, the policy rules will be automatically updated.The preceding paragraph does not contain an exhaustive list of the ways in which reusable and rule-specific conditions should be treated differently. Its purpose is merely to justify making a semantic distinction between rule-specific and reusable, and then reflecting this distinction in the policy repository itself.
When the policy repository is realized in an LDAP-accessible directory, the distinction between rule-specific and reusable conditions and actions is realized via placement of auxiliary classes and via DIT containment. Figure 4 illustrates a policy rule Rule1 with one rule-specific condition CA and one rule-specific action AB.
+-----+ |Rule1| | | +-----|- -|-----+ | +-----+ | | * * | | * * | | **** **** | | * * | v * * v +--------+ +--------+ | CA+ca | | AB+ab | +--------+ +--------+ +------------------------------+ |LEGEND: | | ***** DIT containment | | + auxiliary attachment | | ----> DN reference | +------------------------------+
Figure 4 Rule-Specific Policy Conditions and Actions
-
Because the condition and action are specific to Rule1, the auxiliary classes ca and ab that represent them are attached, respectively, to the structural classes CA and AB. These structural classes represent not the condition ca and action ab themselves, but rather the associations between Rule1 and ca, and between Rule1 and ab.
As Figure 4 illustrates, Rule1 contains DN references to the structural classes CA and AB that appear below it in the DIT. At first glance it might appear that these DN references are unnecessary, since a subtree search below Rule1 would find all of the structural classes representing the associations between Rule1 and its conditions and actions. Relying only on a subtree search, though, runs the risk of missing conditions or actions that should have appeared in the subtree, but for some reason did not, or of finding conditions or actions that were inadvertently placed in the subtree, or that should have been removed from the subtree, but for some reason were not. Implementation experience has suggested that many (but not all) of these risks are eliminated.
However, it must be noted that this comes at a price. The use of DN references, as shown in Figure 4 above, thwarts inheritance of access control information as well as existence dependency information. It also is subject to referential integrity considerations. Therefore, it is being included as an option for the designer.
Figure 5 illustrates a second way of representing rule-specific conditions and actions in an LDAP-accessible directory: attachment of the auxiliary classes directly to the instance representing the policy rule. When all of the conditions and actions are attached to a policy rule in this way, the rule is termed a "simple" policy rule. When conditions and actions are not attached directly to a policy rule, the rule is termed a "complex" policy rule.
+-----------+ |Rule1+ca+ab| | | +-----------+ +------------------------------+ |LEGEND: | | + auxiliary attachment | +------------------------------+
Figure 5. A Simple Policy Rule
-
The simple/complex distinction for a policy rule is not all or nothing. A policy rule may have its conditions attached to itself and its actions attached to other entries, or it may have its actions attached to itself and its conditions attached to other entries. However, it SHALL NOT have either its conditions or its actions attached both to itself and to other entries, with one exception: a policy rule may reference its validity periods with the pcimRuleValidityPeriodList attribute, but have its other conditions attached to itself.
The tradeoffs between simple and complex policy rules are between the efficiency of simple rules and the flexibility and greater potential for reuse of complex rules. With a simple policy rule, the semantic options are limited:
- All conditions are ANDed together. This combination can be represented in two ways in the Disjunctive Normal Form (DNF)/ Conjunctive Normal Form (CNF) (please see [1] for definitions of these terms) expressions characteristic of policy conditions: as a DNF expression with a single AND group, or as a CNF expression with multiple single-condition OR groups. The first of these is arbitrarily chosen as the representation for the ANDed conditions in a simple policy rule. - If multiple actions are included, no order can be specified for them.If a policy administrator needs to combine conditions in some other way, or if there is a set of actions that must be ordered, then the only option is to use a complex policy rule.
Finally, Figure 6 illustrates the same policy rule Rule1, but this time its condition and action are reusable. The association classes CA and AB are still present, and they are still DIT contained under Rule1. But rather than having the auxiliary classes ca and ab attached directly to the association classes CA and AB, each now contains DN references to other entries to which these auxiliary classes are attached. These other entries, CIA and AIB, are DIT contained under RepositoryX, which is an instance of the class pcimRepository. Because they are named under an instance of pcimRepository, ca and ab are clearly identified as reusable.
+-----+ +-------------+ |Rule1| | RepositoryX | +-|- -|--+ | | | +-----+ | +-------------+ | * * | * * | * * | * * | *** **** | * * | * * v * * | * +---+ * * | * |AB | +------+ * v * | -|-------->|AIB+ab| * +---+ +---+ +------+ * |CA | +------+ | -|------------------------>|CIA+ca| +---+ +------+ +------------------------------+ |LEGEND: | | ***** DIT containment | | + auxiliary attachment | | ----> DN reference | +------------------------------+
Figure 6. Reusable Policy Conditions and Actions
-
The classes pcimConditionAuxClass and pcimActionAuxClass do not themselves represent actual conditions and actions: these are introduced in their subclasses. What pcimConditionAuxClass and pcimActionAuxClass do introduce are the semantics of being a policy condition or a policy action. These are the semantics that all the subclasses of pcimConditionAuxClass and pcimActionAuxClass inherit. Among these semantics are those of representing either a rule-specific or a reusable policy condition or policy action.
In order to preserve the ability to represent a rule-specific or a reusable condition or action, as well as a simple policy rule, all the subclasses of pcimConditionAuxClass and pcimActionAuxClass MUST also be auxiliary classes.
4.5. Location and Retrieval of Policy Objects in the Directory
-
When a Policy Decision Point (PDP) goes to an LDAP directory to retrieve the policy object instances relevant to the Policy Enforcement Points (PEPs) it serves, it is faced with two related problems:
- How does it locate and retrieve the directory entries that apply to its PEPs? These entries may include instances of the PCLS classes, instances of domain-specific subclasses of these classes, and instances of other classes modeling such resources as user groups, interfaces, and address ranges. - How does it retrieve the directory entries it needs in an efficient manner, so that retrieval of policy information from the directory does not become a roadblock to scalability? There are two facets to this efficiency: retrieving only the relevant directory entries, and retrieving these entries using as few LDAP calls as possible.The placement of objects in the Directory Information Tree (DIT) involves considerations other than how the policy-related objects will be retrieved by a PDP. Consequently, all that the PCLS can do is to provide a "toolkit" of classes to assist the policy administrator as the DIT is being designed and built. A PDP SHOULD be able to take advantage of any tools that the policy administrator is able to build into the DIT, but it MUST be able to use a less efficient means of retrieval if that is all it has available to it.
The basic idea behind the LDAP optimization classes is a simple one: make it possible for a PDP to retrieve all the policy-related objects it needs, and only those objects, using as few LDAP calls as possible. An important assumption underlying this approach is that the policy administrator has sufficient control over the underlying DIT structure to define subtrees for storing policy information. If the policy administrator does not have this level of control over DIT structure, a PDP can still retrieve the policy-related objects it needs individually. But it will require more LDAP access operations to do the retrieval in this way. Figure 7 illustrates how LDAP optimization is accomplished.
+-----+ ---------------->| A | DN reference to | | DN references to subtrees +---+ starting object +-----+ +-------------------------->| C | | o--+----+ +---+ +---+ | o--+------------->| B | / \ +-----+ +---+ / \ / \ / \ / ... \ / \ / \ / \ / ... \-
Figure 7. Using the pcimSubtreesPtrAuxClass to Locate Policies
The PDP is configured initially with a DN reference to some entry in the DIT. The structural class of this entry is not important; the PDP is interested only in the pcimSubtreesPtrAuxClass attached to it. This auxiliary class contains a multi-valued attribute with DN references to objects that anchor subtrees containing policy-related objects of interest to the PDP. Since pcimSubtreesPtrAuxClass is an auxiliary class, it can be attached to an entry that the PDP would need to access anyway - perhaps an entry containing initial configuration settings for the PDP, or for a PEP that uses the PDP.
Once it has retrieved the DN references, the PDP will direct to each of the objects identified by them an LDAP request that all entries in its subtree be evaluated against the selection criteria specified in the request. The LDAP-enabled directory then returns all entries in that subtree that satisfy the specified criteria.
The selection criteria always specify that object class="pcimPolicy". Since all classes representing policy rules, policy conditions, and policy actions, both in the PCLS and in any domain-specific schema derived from it, are subclasses of the abstract class policy, this criterion evaluates to TRUE for all instances of these classes. To accommodate special cases where a PDP needs to retrieve objects that are not inherently policy-related (for example, an IP address range object referenced by a subclass of pcimActionAuxClass representing the DHCP action "assign from this address range"), the auxiliary class pcimElementAuxClass can be used to "tag" an entry, so that it will be found by the selection criterion "object class=pcimPolicy".
The approach described in the preceding paragraph will not work for certain directory implementations, because these implementations do not support matching of auxiliary classes in the objectClass attribute. For environments where these implementations are expected to be present, the "tagging" of entries as relevant to policy can be accomplished by inserting the special value "POLICY" into the list of values contained in the pcimKeywords attribute (provided by the pcimPolicy class).
If a PDP needs only a subset of the policy-related objects in the indicated subtrees, then it can be configured with additional selection criteria based on the pcimKeywords attribute defined in the pcimPolicy class. This attribute supports both standardized and administrator- defined values. For example, a PDP could be configured to request only those policy-related objects containing the keywords "DHCP" and "Eastern US".
To optimize what is expected to be a typical case, the initial request from the client includes not only the object to which its "seed" DN references, but also the subtree contained under this object. The filter for searching this subtree is whatever the client is going to use later to search the other subtrees: object class="pcimPolicy" or the presence of the keyword "POLICY", and/or presence of a more specific value of pcimKeywords (e.g., "QoS Edge Policy"). Returning to the example in Figure 7, we see that in the best case, a PDP can get all the policy-related objects it needs, and only those objects, with exactly three LDAP requests: one to its starting object A to get the references to B and C, as well as the policy-related objects it needs from the subtree under A, and then one each to B and C to get all the policy-related objects that pass the selection criteria with which it was configured. Once it has retrieved all of these objects, the PDP can then traverse their various DN references locally to understand the semantic relationships among them. The PDP should also be prepared to find a reference to another subtree attached to any of the objects it retrieves, and to follow this reference first, before it follows any of the semantically significant references it has received. This recursion permits a structured approach to identifying related policies. In Figure 7, for example, if the subtree under B includes departmental policies and the one under C includes divisional policies, then there might be a reference from the subtree under C to an object D that roots the subtree of corporate-level policies.
A PDP SHOULD understand the pcimSubtreesPtrAuxClass class, SHOULD be capable of retrieving and processing the entries in the subtrees it references, and SHOULD be capable of doing all of this recursively. The same requirements apply to any other entity needing to retrieve policy information from the directory. Thus, a Policy Management Tool that retrieves policy entries from the directory in order to perform validation and conflict detection SHOULD also understand and be capable of using the pcimSubtreesPtrAuxClass. All of these requirements are "SHOULD"s rather than "MUST"s because an LDAP client that doesn't implement them can still access and retrieve the directory entries it needs. The process of doing so will just be less efficient than it would have been if the client had implemented these optimizations.
When it is serving as a tool for creating policy entries in the directory, a Policy Management Tool SHOULD support creation of pcimSubtreesPtrAuxClass entries and their references to object instances.
-
4.5.1. Aliases and Other DIT-Optimization Techniques
-
Additional flexibility in DIT structure is available to the policy administrator via LDAP aliasing and other techniques. Previous versions of this document have used aliases. However, because aliases are experimental, the use of aliases has been removed from this version of this document. This is because the IETF has yet to produce a specification on how aliases are represented in the directory or how server implementations are to process aliases.
5. Class Definitions
-
The semantics for the policy information classes that are to be mapped directly from the information model to an LDAP representation are detailed in [1]. Consequently, all that this document presents for these classes is the specification for how to do the mapping from the information model (which is independent of repository type and access protocol) to a form that can be accessed using LDAP. Remember that some new classes needed to be created (that were not part of [1]) to implement the LDAP mapping. These new LDAP-only classes are fully documented in this document.
The formal language for specifying the classes, attributes, and DIT structure and content rules is that defined in reference [3]. If your implementation does not support auxiliary class inheritance, you will have to list auxiliary classes in content rules explicitly or define them in another (implementation-specific) way.
The following notes apply to this section in its entirety.
Note 1: in the following definitions, the class and attribute definitions follow RFC 2252 [3] but they are line-wrapped to enhance human readability.
Note 2: where applicable, the possibilities for specifying DIT structure and content rules are noted. However, care must be taken in specifying DIT structure rules. This is because X.501 [4] states that an entry may only exist in the DIT as a subordinate to another superior entry (the superior) if a DIT structure rule exists in the governing subschema which:
1) indicates a name form for the structural object class of the subordinate entry, and 2) either includes the entry's superior structure rule as a possible superior structure rule, or 3) does not specify a superior structure rule.If this last case (3) applies, then the entry is defined to be a subschema administrative point. This is not what is desired. Therefore, care must be taken in defining structure rules, and in particular, they must be locally augmented.
Note 3: Wherever possible, both an equality and a substring matching rule are defined for a particular attribute (as well as an ordering match rule to enable sorting of matching results). This provides two different choices for the developer for maximum flexibility.
For example, consider the pcimRoles attribute (section 5.3). Suppose that a PEP has reported that it is interested in pcimRules for three roles R1, R2, and R3. If the goal is to minimize queries, then the PDP can supply three substring filters containing the three role names.
These queries will return all of the pcimRules that apply to the PEP, but they may also get some that do not apply (e.g., ones that contain one of the roles R1, R2, or R3 and one or more other roles present in a role-combination [1]).
Another strategy would be for the PDP to use only equality filters. This approach eliminates the extraneous replies, but it requires the PDP to explicitly build the desired role-combinations itself. It also requires extra queries. Note that this approach is practical only because the role names in a role combination are required to appear in alphabetical order.
Note 4: in the following definitions, note that all LDAP matching rules are defined in [3] and in [9]. The corresponding X.500 matching rules are defined in [8].
Note 5: some of the following attribute definitions specify additional constraints on various data types (e.g., this integer has values that are valid from 1..10). Text has been added to instruct servers and applications what to do if a value outside of this range
is encountered. In all cases, if a constraint is violated, then the policy rule SHOULD be treated as being disabled, meaning that execution of the policy rule SHOULD be stopped.
5.1. The Abstract Class pcimPolicy
-
The abstract class pcimPolicy is a direct mapping of the abstract class Policy from the PCIM. The class value "pcimPolicy" is also used as the mechanism for identifying policy-related instances in the Directory Information Tree. An instance of any class may be "tagged" with this class value by attaching to it the auxiliary class pcimElementAuxClass. Since pcimPolicy is derived from the class dlm1ManagedElement defined in reference [6], this specification has a normative dependency on that element of reference [6].
The class definition is as follows:
( 1.3.6.1.1.6.1.1 NAME 'pcimPolicy' DESC 'An abstract class that is the base class for all classes that describe policy-related instances.' SUP dlm1ManagedElement ABSTRACT MAY ( cn $ dlmCaption $ dlmDescription $ orderedCimKeys $ pcimKeywords ) )The attribute cn is defined in RFC 2256 [7]. The dlmCaption, dlmDescription, and orderedCimKeys attributes are defined in [6].
The pcimKeywords attribute is a multi-valued attribute that contains a set of keywords to assist directory clients in locating the policy objects identified by these keywords. It is defined as follows:
( 1.3.6.1.1.6.2.3 NAME 'pcimKeywords' DESC 'A set of keywords to assist directory clients in locating the policy objects applicable to them.' EQUALITY caseIgnoreMatch ORDERING caseIgnoreOrderingMatch SUBSTR caseIgnoreSubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 )
5.2. The Three Policy Group Classes
-
PCIM [1] defines the PolicyGroup class to serve as a generalized aggregation mechanism, enabling PolicyRules and/or PolicyGroups to be aggregated together. PCLS maps this class into three LDAP classes, called pcimGroup, pcimGroupAuxClass, and pcimGroupInstance. This is done in order to provide maximum flexibility for the DIT designer.
The class definitions for the three policy group classes are listed below. These class definitions do not include attributes to realize the PolicyRuleInPolicyGroup and PolicyGroupInPolicyGroup associations from the PCIM. This is because a pcimGroup object refers to instances of pcimGroup and pcimRule via, respectively, the attribute pcimGroupsAuxContainedSet in the pcimGroupContainmentAuxClass object class and the attribute pcimRulesAuxContainedSet in the pcimRuleContainmentAuxClass object class.
To maximize flexibility, the pcimGroup class is defined as abstract. The subclass pcimGroupAuxClass provides for auxiliary attachment to another entry, while the structural subclass pcimGroupInstance is available to represent a policy group as a standalone entry.
The class definitions are as follows. First, the definition of the abstract class pcimGroup:
( 1.3.6.1.1.6.1.2 NAME 'pcimGroup' DESC 'A container for a set of related pcimRules and/or a set of related pcimGroups.' SUP pcimPolicy ABSTRACT MAY ( pcimGroupName ) )The one attribute of pcimGroup is pcimGroupName. This attribute is used to define a user-friendly name of this policy group, and may be used as a naming attribute if desired. It is defined as follows:
( 1.3.6.1.1.6.2.4 NAME 'pcimGroupName' DESC 'The user-friendly name of this policy group.' EQUALITY caseIgnoreMatch ORDERING caseIgnoreOrderingMatch SUBSTR caseIgnoreSubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 SINGLE-VALUE )The two subclasses of pcimGroup are defined as follows. The class pcimGroupAuxClass is an auxiliary class that can be used to collect a set of related pcimRule and/or pcimGroup classes. It is defined as follows:
( 1.3.6.1.1.6.1.3 NAME 'pcimGroupAuxClass' DESC 'An auxiliary class that collects a set of related pcimRule and/or pcimGroup entries.' SUP pcimGroup AUXILIARY )The class pcimGroupInstance is a structural class that can be used to collect a set of related pcimRule and/or pcimGroup classes. It is defined as follows:
( 1.3.6.1.1.6.1.4 NAME 'pcimGroupInstance' DESC 'A structural class that collects a set of related pcimRule and/or pcimGroup entries.' SUP pcimGroup STRUCTURAL )A DIT content rule could be written to enable an instance of pcimGroupInstance to have attached to it either references to one or more policy groups (using pcimGroupContainmentAuxClass) or references to one or more policy rules (using pcimRuleContainmentAuxClass). This would be used to formalize the semantics of the PolicyGroup class [1]. Since these semantics do not include specifying any properties of the PolicyGroup class, the content rule would not need to specify any attributes.
Similarly, three separate DIT structure rules could be written, each of which would refer to a specific name form that identified one of the three possible naming attributes (i.e., pcimGroupName, cn, and orderedCIMKeys) for the pcimGroup object class. This structure rule SHOULD include a superiorStructureRule (see Note 2 at the beginning of section 5). The three name forms referenced by the three structure rules would each define one of the three naming attributes.
5.3. The Three Policy Rule Classes
-
The information model defines a PolicyRule class to represent the "If Condition then Action" semantics associated with processing policy information. For maximum flexibility, the PCLS maps this class into three LDAP classes.
To maximize flexibility, the pcimRule class is defined as abstract. The subclass pcimRuleAuxClass provides for auxiliary attachment to another entry, while the structural subclass pcimRuleInstance is available to represent a policy rule as a standalone entry.
The conditions and actions associated with a policy rule are modeled, respectively, with auxiliary subclasses of the auxiliary classes pcimConditionAuxClass and pcimActionAuxClass. Each of these auxiliary subclasses is attached to an instance of one of three structural classes. A subclass of pcimConditionAuxClass is attached to an instance of pcimRuleInstance, to an instance of pcimRuleConditionAssociation, or to an instance of pcimPolicyInstance. Similarly, a subclass of pcimActionAuxClass is attached to an instance of pcimRuleInstance, to an instance of pcimRuleActionAssociation, or to an instance of pcimPolicyInstance.
The pcimRuleValidityPeriodList attribute (defined below) realizes the PolicyRuleValidityPeriod association defined in the PCIM. Since this association has no additional properties besides those that tie the association to its associated objects, this association can be realized by simply using an attribute. Thus, the pcimRuleValidityPeriodList attribute is simply a multi-valued attribute that provides an unordered set of DN references to one or more instances of the pcimTPCAuxClass, indicating when the policy rule is scheduled to be active and when it is scheduled to be inactive. A policy rule is scheduled to be active if it is active according to AT LEAST ONE of the pcimTPCAuxClass instances referenced by this attribute.
The PolicyConditionInPolicyRule and PolicyActionInPolicyRule associations, however, do have additional attributes. The association PolicyActionInPolicyRule defines an integer attribute to sequence the actions, and the association PolicyConditionInPolicyRule has both an integer attribute to group the condition terms as well as a Boolean property to specify whether a condition is to be negated.
In the PCLS, these additional association attributes are represented as attributes of two classes introduced specifically to model these associations. These classes are the pcimRuleConditionAssociation class and the pcimRuleActionAssociation class, which are defined in Sections 5.4 and 5.5, respectively. Thus, they do not appear as attributes of the class pcimRule. Instead, the pcimRuleConditionList and pcimRuleActionList attributes can be used to reference these classes.
The class definitions for the three pcimRule classes are as follows.
The abstract class pcimRule is a base class for representing the "If Condition then Action" semantics associated with a policy rule. It is defined as follows:
( 1.3.6.1.1.6.1.5 NAME 'pcimRule' DESC 'The base class for representing the "If Condition then Action" semantics associated with a policy rule.' SUP pcimPolicy ABSTRACT MAY ( pcimRuleName $ pcimRuleEnabled $ pcimRuleConditionListType $ pcimRuleConditionList $ pcimRuleActionList $ pcimRuleValidityPeriodList $ pcimRuleUsage $ pcimRulePriority $ pcimRuleMandatory $ pcimRuleSequencedActions $ pcimRoles ) )The PCIM [1] defines seven properties for the PolicyRule class. The PCLS defines eleven attributes for the pcimRule class, which is the LDAP equivalent of the PolicyRule class. Of these eleven attributes, seven are mapped directly from corresponding properties in PCIM's PolicyRule class. The remaining four attributes are a class-specific optional naming attribute, and three attributes used to realize the three associations that the pcimRule class participates in.
The pcimRuleName attribute is used as a user-friendly name of this policy rule, and can also serve as the class-specific optional naming attribute. It is defined as follows:
( 1.3.6.1.1.6.2.5 NAME 'pcimRuleName' DESC 'The user-friendly name of this policy rule.' EQUALITY caseIgnoreMatch ORDERING caseIgnoreOrderingMatch SUBSTR caseIgnoreSubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 SINGLE-VALUE )The pcimRuleEnabled attribute is an integer enumeration indicating whether a policy rule is administratively enabled (value=1), administratively disabled (value=2), or enabled for debug (value=3). It is defined as follows:
( 1.3.6.1.1.6.2.6 NAME 'pcimRuleEnabled' DESC 'An integer indicating whether a policy rule is administratively enabled (value=1), disabled (value=2), or enabled for debug (value=3).' EQUALITY integerMatch ORDERING integerOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE )Note: All other values for the pcimRuleEnabled attribute are considered errors, and the administrator SHOULD treat this rule as being disabled if an invalid value is found.
The pcimRuleConditionListType attribute is used to indicate whether the list of policy conditions associated with this policy rule is in disjunctive normal form (DNF, value=1) or conjunctive normal form (CNF, value=2). It is defined as follows:
( 1.3.6.1.1.6.2.7 NAME 'pcimRuleConditionListType' DESC 'A value of 1 means that this policy rule is in disjunctive normal form; a value of 2 means that this policy rule is in conjunctive normal form.' EQUALITY integerMatch ORDERING integerOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE )Note: any value other than 1 or 2 for the pcimRuleConditionListType attribute is considered an error. Administrators SHOULD treat this rule as being disabled if an invalid value is found, since it is unclear how to structure the condition list.
The pcimRuleConditionList attribute is a multi-valued attribute that is used to realize the policyRuleInPolicyCondition association defined in [1]. It contains a set of DNs of pcimRuleConditionAssociation entries representing associations between this policy rule and its conditions. No order is implied. It is defined as follows:
( 1.3.6.1.1.6.2.8 NAME 'pcimRuleConditionList' DESC 'Unordered set of DNs of pcimRuleConditionAssociation entries representing associations between this policy rule and its conditions.' EQUALITY distinguishedNameMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.12 )The pcimRuleActionList attribute is a multi-valued attribute that is used to realize the policyRuleInPolicyAction association defined in [1]. It contains a set of DNs of pcimRuleActionAssociation entries representing associations between this policy rule and its actions. No order is implied. It is defined as follows:
( 1.3.6.1.1.6.2.9 NAME 'pcimRuleActionList' DESC 'Unordered set of DNs of pcimRuleActionAssociation entries representing associations between this policy rule and its actions.' EQUALITY distinguishedNameMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.12 )The pcimRuleValidityPeriodList attribute is a multi-valued attribute that is used to realize the pcimRuleValidityPeriod association that is defined in [1]. It contains a set of DNs of pcimRuleValidityAssociation entries that determine when the pcimRule is scheduled to be active or inactive. No order is implied. It is defined as follows:
( 1.3.6.1.1.6.2.10 NAME 'pcimRuleValidityPeriodList' DESC 'Unordered set of DNs of pcimRuleValidityAssociation entries that determine when the pcimRule is scheduled to be active or inactive.' EQUALITY distinguishedNameMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.12 )The pcimRuleUsage attribute is a free-form string providing guidelines on how this policy should be used. It is defined as follows:
( 1.3.6.1.1.6.2.11 NAME 'pcimRuleUsage' DESC 'This attribute is a free-form sting providing guidelines on how this policy should be used.' EQUALITY caseIgnoreMatch ORDERING caseIgnoreOrderingMatch SUBSTR caseIgnoreSubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 SINGLE-VALUE )The pcimRulePriority attribute is a non-negative integer that is used to prioritize this pcimRule relative to other pcimRules. A larger value indicates a higher priority. It is defined as follows:
( 1.3.6.1.1.6.2.12 NAME 'pcimRulePriority' DESC 'A non-negative integer for prioritizing this pcimRule relative to other pcimRules. A larger value indicates a higher priority.' EQUALITY integerMatch ORDERING integerOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE )Note: if the value of the pcimRulePriority field is 0, then it SHOULD be treated as "don't care". On the other hand, if the value is negative, then it SHOULD be treated as an error and Administrators SHOULD treat this rule as being disabled.
The pcimRuleMandatory attribute is a Boolean attribute that, if TRUE, indicates that for this policy rule, the evaluation of its conditions and execution of its actions (if the condition is satisfied) is required. If it is FALSE, then the evaluation of its conditions and execution of its actions (if the condition is satisfied) is not required. This attribute is defined as follows:
( 1.3.6.1.1.6.2.13 NAME 'pcimRuleMandatory' DESC 'If TRUE, indicates that for this policy rule, the evaluation of its conditions and execution of its actions (if the condition is satisfied) is required.' EQUALITY booleanMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.7 SINGLE-VALUE ) The pcimRuleSequencedActions attribute is an integer enumeration that is used to indicate that the ordering of actions defined by the pcimActionOrder attribute is either mandatory(value=1), recommended(value=2), or dontCare(value=3). It is defined as follows: ( 1.3.6.1.1.6.2.14 NAME 'pcimRuleSequencedActions' DESC 'An integer enumeration indicating that the ordering of actions defined by the pcimActionOrder attribute is mandatory(1), recommended(2), or dontCare(3).' EQUALITY integerMatch ORDERING integerOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE )Note: if the value of pcimRulesSequencedActions field is not one of these three values, then Administrators SHOULD treat this rule as being disabled.
The pcimRoles attribute represents the policyRoles property of [1]. Each value of this attribute represents a role-combination, which is a string of the form: <RoleName>[&&<RoleName>]* where the individual role names appear in alphabetical order according to the collating sequence for UCS-2. This attribute is defined as follows: ( 1.3.6.1.1.6.2.15 NAME 'pcimRoles' DESC 'Each value of this attribute represents a role- combination.' EQUALITY caseIgnoreMatch ORDERING caseIgnoreOrderingMatch SUBSTR caseIgnoreSubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 )Note: if the value of the pcimRoles attribute does not conform to the format "<RoleName>[&&<RoleName>]*" (see Section 6.3.7 of [1]), then this attribute is malformed and its policy rule SHOULD be treated as being disabled.
The two subclasses of the pcimRule class are defined as follows. First, the pcimRuleAuxClass is an auxiliary class for representing the "If Condition then Action" semantics associated with a policy rule. Its class definition is as follows:
( 1.3.6.1.1.6.1.6 NAME 'pcimRuleAuxClass' DESC 'An auxiliary class for representing the "If Condition then Action" semantics associated with a policy rule.' SUP pcimRule AUXILIARY )The pcimRuleInstance is a structural class for representing the "If Condition then Action" semantics associated with a policy rule. Its class definition is as follows:
( 1.3.6.1.1.6.1.7 NAME 'pcimRuleInstance' DESC 'A structural class for representing the "If Condition then Action" semantics associated with a policy rule.' SUP pcimRule STRUCTURAL )A DIT content rule could be written to enable an instance of pcimRuleInstance to have attached to it either references to one or more policy conditions (using pcimConditionAuxClass) or references to one or more policy actions (using pcimActionAuxClass). This would be used to formalize the semantics of the PolicyRule class [1]. Since these semantics do not include specifying any properties of the PolicyRule class, the content rule would not need to specify any attributes.
Similarly, three separate DIT structure rules could be written, each of which would refer to a specific name form that identified one of its three possible naming attributes (i.e., pcimRuleName, cn, and orderedCIMKeys). This structure rule SHOULD include a superiorStructureRule (see Note 2 at the beginning of section 5). The three name forms referenced by the three structure rules would each define one of the three naming attributes.
5.4. The Class pcimRuleConditionAssociation
-
This class contains attributes to represent the properties of the PCIM's PolicyConditionInPolicyRule association. Instances of this class are related to an instance of pcimRule via DIT containment. The policy conditions themselves are represented by auxiliary subclasses of the auxiliary class pcimConditionAuxClass. These auxiliary classes are attached directly to instances of pcimRuleConditionAssociation for rule-specific policy conditions. For a reusable policy condition, the policyCondition auxiliary subclass is attached to an instance of the class pcimPolicyInstance (which is presumably associated with a pcimRepository by DIT containment), and the policyConditionDN attribute (of this class) is used to reference the reusable policyCondition instance.
The class definition is as follows:
( 1.3.6.1.1.6.1.8 NAME 'pcimRuleConditionAssociation' DESC 'This class contains attributes characterizing the relationship between a policy rule and one of its policy conditions.' SUP pcimPolicy MUST ( pcimConditionGroupNumber $ pcimConditionNegated ) MAY ( pcimConditionName $ pcimConditionDN ) )The attributes of this class are defined as follows.
The pcimConditionGroupNumber attribute is a non-negative integer. It is used to identify the group to which the condition referenced by this association is assigned. This attribute is defined as follows:
( 1.3.6.1.1.6.2.16 NAME 'pcimConditionGroupNumber' DESC 'The number of the group to which a policy condition belongs. This is used to form the DNF or CNF expression associated with a policy rule.' EQUALITY integerMatch ORDERING integerOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE )Note that this number is non-negative. A negative value for this attribute is invalid, and any policy rule that refers to an invalid entry SHOULD be treated as being disabled.
The pcimConditionNegated attribute is a Boolean attribute that indicates whether this policy condition is to be negated or not. If it is TRUE (FALSE), it indicates that a policy condition IS (IS NOT) negated in the DNF or CNF expression associated with a policy rule. This attribute is defined as follows:
( 1.3.6.1.1.6.2.17 NAME 'pcimConditionNegated' DESC 'If TRUE (FALSE), it indicates that a policy condition IS (IS NOT) negated in the DNF or CNF expression associated with a policy rule.' EQUALITY booleanMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.7 SINGLE-VALUE )The pcimConditionName is a user-friendly name for identifying this policy condition, and may be used as a naming attribute if desired. This attribute is defined as follows:
( 1.3.6.1.1.6.2.18 NAME 'pcimConditionName' DESC 'A user-friendly name for a policy condition.' EQUALITY caseIgnoreMatch ORDERING caseIgnoreOrderingMatch SUBSTR caseIgnoreSubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 SINGLE-VALUE )The pcimConditionDN attribute is a DN that references an instance of a reusable policy condition. This attribute is defined as follows:
( 1.3.6.1.1.6.2.19 NAME 'pcimConditionDN' DESC 'A DN that references an instance of a reusable policy condition.' EQUALITY distinguishedNameMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.12 SINGLE-VALUE )A DIT content rule could be written to enable an instance of pcimRuleConditionAssociation to have attached to it an instance of the auxiliary class pcimConditionAuxClass, or one of its subclasses. This would be used to formalize the semantics of the PolicyConditionInPolicyRule association. Specifically, this would be used to represent a rule-specific policy condition [1]. Similarly, three separate DIT structure rules could be written. Each of these DIT structure rules would refer to a specific name form that defined two important semantics. First, each name form would identify one of the three possible naming attributes (i.e., pcimConditionName, cn, and orderedCIMKeys) for the pcimRuleConditionAssociation object class. Second, each name form would require that an instance of the pcimRuleConditionAssociation class have as its superior an instance of the pcimRule class. This structure rule SHOULD also include a superiorStructureRule (see Note 2 at the beginning of section 5).
5.5. The Class pcimRuleValidityAssociation
-
The policyRuleValidityPeriod aggregation is mapped to the PCLS pcimRuleValidityAssociation class. This class represents the scheduled activation and deactivation of a policy rule by binding the definition of times that the policy is active to the policy rule itself. The "scheduled" times are either identified through an attached auxiliary class pcimTPCAuxClass, or are referenced through its pcimTimePeriodConditionDN attribute.
This class is defined as follows:
( 1.3.6.1.1.6.1.9 NAME 'pcimRuleValidityAssociation' DESC 'This defines the scheduled activation or deactivation of a policy rule.' SUP pcimPolicy STRUCTURAL MAY ( pcimValidityConditionName $ pcimTimePeriodConditionDN ) )The attributes of this class are defined as follows:
The pcimValidityConditionName attribute is used to define a user-friendly name of this condition, and may be used as a naming attribute if desired. This attribute is defined as follows:
( 1.3.6.1.1.6.2.20 NAME 'pcimValidityConditionName' DESC 'A user-friendly name for identifying an instance of a pcimRuleValidityAssociation entry.' EQUALITY caseIgnoreMatch ORDERING caseIgnoreOrderingMatch SUBSTR caseIgnoreSubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 SINGLE-VALUE )The pcimTimePeriodConditionDN attribute is a DN that references a reusable time period condition. It is defined as follows:
( 1.3.6.1.1.6.2.21 NAME 'pcimTimePeriodConditionDN' DESC 'A reference to a reusable policy time period condition.' EQUALITY distinguishedNameMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.12 SINGLE-VALUE )A DIT content rule could be written to enable an instance of pcimRuleValidityAssociation to have attached to it an instance of the auxiliary class pcimTPCAuxClass, or one of its subclasses. This would be used to formalize the semantics of the PolicyRuleValidityPeriod aggregation [1].
Similarly, three separate DIT structure rules could be written. Each of these DIT structure rules would refer to a specific name form that defined two important semantics. First, each name form would identify one of the three possible naming attributes (i.e., pcimValidityConditionName, cn, and orderedCIMKeys) for the pcimRuleValidityAssociation object class. Second, each name form would require that an instance of the pcimRuleValidityAssociation class have as its superior an instance of the pcimRule class. This structure rule SHOULD also include a superiorStructureRule (see Note 2 at the beginning of section 5).
5.6. The Class pcimRuleActionAssociation
-
This class contains an attribute to represent the one property of the PCIM PolicyActionInPolicyRule association, ActionOrder. This property is used to specify an order for executing the actions associated with a policy rule. Instances of this class are related to an instance of pcimRule via DIT containment. The actions themselves are represented by auxiliary subclasses of the auxiliary class pcimActionAuxClass.
These auxiliary classes are attached directly to instances of pcimRuleActionAssociation for rule-specific policy actions. For a reusable policy action, the pcimAction auxiliary subclass is attached to an instance of the class pcimPolicyInstance (which is presumably associated with a pcimRepository by DIT containment), and the pcimActionDN attribute (of this class) is used to reference the reusable pcimCondition instance.
The class definition is as follows:
( 1.3.6.1.1.6.1.10 NAME 'pcimRuleActionAssociation' DESC 'This class contains attributes characterizing the relationship between a policy rule and one of its policy actions.' SUP pcimPolicy MUST ( pcimActionOrder ) MAY ( pcimActionName $ pcimActionDN ) )The pcimActionName attribute is used to define a user-friendly name of this action, and may be used as a naming attribute if desired. This attribute is defined as follows:
( 1.3.6.1.1.6.2.22 NAME 'pcimActionName' DESC 'A user-friendly name for a policy action.' EQUALITY caseIgnoreMatch ORDERING caseIgnoreOrderingMatch SUBSTR caseIgnoreSubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 SINGLE-VALUE )The pcimActionOrder attribute is an unsigned integer that is used to indicate the relative position of an action in a sequence of actions that are associated with a given policy rule. When this number is positive, it indicates a place in the sequence of actions to be performed, with smaller values indicating earlier positions in the sequence. If the value is zero, then this indicates that the order is irrelevant. Note that if two or more actions have the same non-zero value, they may be performed in any order as long as they are each performed in the correct place in the overall sequence of actions. This attribute is defined as follows:
( 1.3.6.1.1.6.2.23 NAME 'pcimActionOrder' DESC 'An integer indicating the relative order of an action in the context of a policy rule.' EQUALITY integerMatch ORDERING integerOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE )Note: if the value of the pcimActionOrder field is negative, then it SHOULD be treated as an error and any policy rule that refers to such an entry SHOULD be treated as being disabled.
The pcimActionDN attribute is a DN that references a reusable policy action. It is defined as follows:
( 1.3.6.1.1.6.2.24 NAME 'pcimActionDN' DESC 'A DN that references a reusable policy action.' EQUALITY distinguishedNameMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.12 SINGLE-VALUE )A DIT content rule could be written to enable an instance of pcimRuleActionAssociation to have attached to it an instance of the auxiliary class pcimActionAuxClass, or one of its subclasses. This would be used to formalize the semantics of the PolicyActionInPolicyRule association. Specifically, this would be used to represent a rule-specific policy action [1].
Similarly, three separate DIT structure rules could be written. Each of these DIT structure rules would refer to a specific name form that defined two important semantics. First, each name form would identify one of the three possible naming attributes (i.e., pcimActionName, cn, and orderedCIMKeys) for the pcimRuleActionAssociation object class. Second, each name form would require that an instance of the pcimRuleActionAssociation class have as its superior an instance of the pcimRule class. This structure rule should also include a superiorStructureRule (see Note 2 at the beginning of section 5).
5.7. The Auxiliary Class pcimConditionAuxClass
-
The purpose of a policy condition is to determine whether or not the set of actions (contained in the pcimRule that the condition applies to) should be executed or not. This class defines the basic organizational semantics of a policy condition, as specified in [1]. Subclasses of this auxiliary class can be attached to instances of three other classes in the PCLS. When a subclass of this class is attached to an instance of pcimRuleConditionAssociation, or to an instance of pcimRule, it represents a rule-specific policy condition. When a subclass of this class is attached to an instance of pcimPolicyInstance, it represents a reusable policy condition.
Since all of the classes to which subclasses of this auxiliary class may be attached are derived from the pcimPolicy class, the attributes of pcimPolicy will already be defined for the entries to which these subclasses attach. Thus, this class is derived directly from "top".
The class definition is as follows:
( 1.3.6.1.1.6.1.11 NAME 'pcimConditionAuxClass' DESC 'A class representing a condition to be evaluated in conjunction with a policy rule.' SUP top AUXILIARY )
5.8. The Auxiliary Class pcimTPCAuxClass
-
The PCIM defines a time period class, PolicyTimePeriodCondition, to provide a means of representing the time periods during which a policy rule is valid, i.e., active. It also defines an aggregation, PolicyRuleValidityPeriod, so that time periods can be associated with a PolicyRule. The LDAP mapping also provides two classes, one for the time condition itself, and one for the aggregation.
In the PCIM, the time period class is named PolicyTimePeriodCondition. However, the resulting name of the auxiliary class in this mapping (pcimTimePeriodConditionAuxClass) exceeds the length of a name that some directories can store. Therefore, the name has been shortened to pcimTPCAuxClass.
The class definition is as follows:
( 1.3.6.1.1.6.1.12 NAME 'pcimTPCAuxClass' DESC 'This provides the capability of enabling or disabling a policy rule according to a predetermined schedule.' SUP pcimConditionAuxClass AUXILIARY MAY ( pcimTPCTime $ pcimTPCMonthOfYearMask $ pcimTPCDayOfMonthMask $ pcimTPCDayOfWeekMask $ pcimTPCTimeOfDayMask $ pcimTPCLocalOrUtcTime ) )The attributes of the pcimTPCAuxClass are defined as follows.
The pcimTPCTime attribute represents the time period that a policy rule is enabled for. This attribute is defined as a string in [1] with a special format which defines a time period with a starting date and an ending date separated by a forward slash ("/"), as follows:
yyyymmddThhmmss/yyyymmddThhmmss
where the first date and time may be replaced with the string "THISANDPRIOR" or the second date and time may be replaced with the string "THISANDFUTURE". This attribute is defined as follows:
( 1.3.6.1.1.6.2.25 NAME 'pcimTPCTime' DESC 'The start and end times on which a policy rule is valid.' EQUALITY caseIgnoreMatch ORDERING caseIgnoreOrderingMatch SUBSTR caseIgnoreSubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.44 SINGLE-VALUE )The value of this attribute SHOULD be checked against its defined format ("yyyymmddThhmmss/yyyymmddThhmmss", where the first and second date strings may be replaced with the strings "THISANDPRIOR" and "THISANDFUTURE"). If the value of this attribute does not conform to this syntax, then this SHOULD be considered an error and the policy rule SHOULD be treated as being disabled.
The next four attributes (pcimTPCMonthOfYearMask, pcimTPCDayOfMonthMask, pcimTPCDayOfWeekMask, and pcimTPCTimeOfDayMask) are all defined as octet strings in [1]. However, the semantics of each of these attributes are contained in bit strings of various fixed lengths. Therefore, the PCLS uses a syntax of Bit String to represent each of them. The definition of these four attributes are as follows.
The pcimTPCMonthOfYearMask attribute defines a 12-bit mask identifying the months of the year in which a policy rule is valid. The format is a bit string of length 12, representing the months of the year from January through December. The definition of this attribute is as follows:
( 1.3.6.1.1.6.2.26 NAME 'pcimTPCMonthOfYearMask' DESC 'This identifies the valid months of the year for a policy rule using a 12-bit string that represents the months of the year from January through December.' EQUALITY bitStringMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.6 SINGLE-VALUE )The value of this attribute SHOULD be checked against its defined format. If the value of this attribute does not conform to this syntax, then this SHOULD be considered an error and the policy rule SHOULD be treated as being disabled.
The pcimTPCMonthOfDayMask attribute defines a mask identifying the days of the month on which a policy rule is valid. The format is a bit string of length 62. The first 31 positions represent the days of the month in ascending order, from day 1 to day 31. The next 31 positions represent the days of the month in descending order, from the last day to the day 31 days from the end. The definition of this attribute is as follows:
( 1.3.6.1.1.6.2.27 NAME 'pcimTPCDayOfMonthMask' DESC 'This identifies the valid days of the month for a policy rule using a 62-bit string. The first 31 positions represent the days of the month in ascending order, and the next 31 positions represent the days of the month in descending order.' EQUALITY bitStringMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.6 SINGLE-VALUE )The value of this attribute SHOULD be checked against its defined format. If the value of this attribute does not conform to this syntax, then this SHOULD be considered an error and the policy rule SHOULD be treated as being disabled.
The pcimTPCDayOfWeekMask attribute defines a mask identifying the days of the week on which a policy rule is valid. The format is a bit string of length 7, representing the days of the week from Sunday through Saturday. The definition of this attribute is as follows:
( 1.3.6.1.1.6.2.28 NAME 'pcimTPCDayOfWeekMask' DESC 'This identifies the valid days of the week for a policy rule using a 7-bit string. This represents the days of the week from Sunday through Saturday.' EQUALITY bitStringMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.6 SINGLE-VALUE )The value of this attribute SHOULD be checked against its defined format. If the value of this attribute does not conform to this syntax, then this SHOULD be considered an error and the policy rule SHOULD be treated as being disabled.
The pcimTPCTimeOfDayMask attribute defines the range of times at which a policy rule is valid. If the second time is earlier than the first, then the interval spans midnight. The format of the string is Thhmmss/Thhmmss. The definition of this attribute is as follows:
( 1.3.6.1.1.6.2.29 NAME 'pcimTPCTimeOfDayMask' DESC 'This identifies the valid range of times for a policy using the format Thhmmss/Thhmmss.' EQUALITY caseIgnoreMatch ORDERING caseIgnoreOrderingMatch SUBSTR caseIgnoreSubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.44 SINGLE-VALUE )The value of this attribute SHOULD be checked against its defined format. If the value of this attribute does not conform to this syntax, then this SHOULD be considered an error and the policy rule SHOULD be treated as being disabled.
Finally, the pcimTPCLocalOrUtcTime attribute is used to choose between local or UTC time representation. This is mapped as a simple integer syntax, with the value of 1 representing local time and the value of 2 representing UTC time. The definition of this attribute is as follows:
( 1.3.6.1.1.6.2.30 NAME 'pcimTPCLocalOrUtcTime' DESC 'This defines whether the times in this instance represent local (value=1) times or UTC (value=2) times.' EQUALITY integerMatch ORDERING integerOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE )Note: if the value of the pcimTPCLocalOrUtcTime is not 1 or 2, then this SHOULD be considered an error and the policy rule SHOULD be disabled. If the attribute is not present at all, then all times are interpreted as if it were present with the value 2, that is, UTC time.
5.9. The Auxiliary Class pcimConditionVendorAuxClass
-
This class provides a general extension mechanism for representing policy conditions that have not been modeled with specific properties. Instead, its two properties are used to define the content and format of the condition, as explained below. This class is intended for vendor-specific extensions that are not amenable to using pcimCondition; standardized extensions SHOULD NOT use this class.
The class definition is as follows:
( 1.3.6.1.1.6.1.13 NAME 'pcimConditionVendorAuxClass' DESC 'A class that defines a registered means to describe a policy condition.' SUP pcimConditionAuxClass AUXILIARY MAY ( pcimVendorConstraintData $ pcimVendorConstraintEncoding ) )The pcimVendorConstraintData attribute is a multi-valued attribute. It provides a general mechanism for representing policy conditions that have not been modeled as specific attributes. This information is encoded in a set of octet strings. The format of the octet strings is identified by the OID stored in the pcimVendorConstraintEncoding attribute. This attribute is defined as follows:
( 1.3.6.1.1.6.2.31 NAME 'pcimVendorConstraintData' DESC 'Mechanism for representing constraints that have not been modeled as specific attributes. Their format is identified by the OID stored in the attribute pcimVendorConstraintEncoding.' EQUALITY octetStringMatch ORDERING octetStringOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.40 )The pcimVendorConstraintEncoding attribute is used to identify the format and semantics for the pcimVendorConstraintData attribute. This attribute is defined as follows:
( 1.3.6.1.1.6.2.32 NAME 'pcimVendorConstraintEncoding' DESC 'An OID identifying the format and semantics for the pcimVendorConstraintData for this instance.' EQUALITY objectIdentifierMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.38 SINGLE-VALUE )
5.10. The Auxiliary Class pcimActionAuxClass
-
The purpose of a policy action is to execute one or more operations that will affect network traffic and/or systems, devices, etc. in order to achieve a desired policy state. This class is used to represent an action to be performed as a result of a policy rule whose condition clause was satisfied.
Subclasses of this auxiliary class can be attached to instances of three other classes in the PCLS. When a subclass of this class is attached to an instance of pcimRuleActionAssociation, or to an instance of pcimRule, it represents a rule-specific policy action. When a subclass of this class is attached to an instance of pcimPolicyInstance, it represents a reusable policy action.
Since all of the classes to which subclasses of this auxiliary class may be attached are derived from the pcimPolicy class, the attributes of the pcimPolicy class will already be defined for the entries to which these subclasses attach. Thus, this class is derived directly from "top".
The class definition is as follows:
( 1.3.6.1.1.6.1.14 NAME 'pcimActionAuxClass' DESC 'A class representing an action to be performed as a result of a policy rule.' SUP top AUXILIARY )
5.11. The Auxiliary Class pcimActionVendorAuxClass
-
The purpose of this class is to provide a general extension mechanism for representing policy actions that have not been modeled with specific properties. Instead, its two properties are used to define the content and format of the action, as explained below.
As its name suggests, this class is intended for vendor-specific extensions that are not amenable to using the standard pcimAction class. Standardized extensions SHOULD NOT use this class.
The class definition is as follows:
( 1.3.6.1.1.6.1.15 NAME 'pcimActionVendorAuxClass' DESC 'A class that defines a registered means to describe a policy action.' SUP pcimActionAuxClass AUXILIARY MAY ( pcimVendorActionData $ pcimVendorActionEncoding ) )The pcimVendorActionData attribute is a multi-valued attribute. It provides a general mechanism for representing policy actions that have not been modeled as specific attributes. This information is encoded in a set of octet strings. The format of the octet strings is identified by the OID stored in the pcimVendorActionEncoding attribute. This attribute is defined as follows:
( 1.3.6.1.1.6.2.33 NAME 'pcimVendorActionData' DESC ' Mechanism for representing policy actions that have not been modeled as specific attributes. Their format is identified by the OID stored in the attribute pcimVendorActionEncoding.' EQUALITY octetStringMatch ORDERING octetStringOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.40 )The pcimVendorActionEncoding attribute is used to identify the format and semantics for the pcimVendorActionData attribute. This attribute is defined as follows:
( 1.3.6.1.1.6.2.34 NAME 'pcimVendorActionEncoding' DESC 'An OID identifying the format and semantics for the pcimVendorActionData attribute of this instance.' EQUALITY objectIdentifierMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.38 SINGLE-VALUE )
5.12. The Class pcimPolicyInstance
-
This class is not defined in the PCIM. Its role is to serve as a structural class to which auxiliary classes representing policy information are attached when the information is reusable. For auxiliary classes representing policy conditions and policy actions, there are alternative structural classes that may be used. See Section 4.4 for a complete discussion of reusable policy conditions and actions, and of the role that this class plays in how they are represented.
The class definition is as follows:
( 1.3.6.1.1.6.1.16 NAME 'pcimPolicyInstance' DESC 'A structural class to which aux classes containing reusable policy information can be attached.' SUP pcimPolicy MAY ( pcimPolicyInstanceName ) )The pcimPolicyInstanceName attribute is used to define a user-friendly name of this class, and may be used as a naming attribute if desired. It is defined as follows:
( 1.3.6.1.1.6.2.35 NAME 'pcimPolicyInstanceName' DESC 'The user-friendly name of this policy instance.' EQUALITY caseIgnoreMatch ORDERING caseIgnoreOrderingMatch SUBSTR caseIgnoreSubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 SINGLE-VALUE )A DIT content rule could be written to enable an instance of pcimPolicyInstance to have attached to it either instances of one or more of the auxiliary object classes pcimConditionAuxClass and pcimActionAuxClass. Since these semantics do not include specifying any properties, the content rule would not need to specify any attributes. Note that other content rules could be defined to enable other policy-related auxiliary classes to be attached to pcimPolicyInstance.
Similarly, three separate DIT structure rules could be written. Each of these DIT structure rules would refer to a specific name form that defined two important semantics. First, each name form would identify one of the three possible naming attributes (i.e., pcimPolicyInstanceName, cn, and orderedCIMKeys) for this object class. Second, each name form would require that an instance of the pcimPolicyInstance class have as its superior an instance of the pcimRepository class. This structure rule SHOULD also include a superiorStructureRule (see Note 2 at the beginning of section 5).
5.13. The Auxiliary Class pcimElementAuxClass
-
This class introduces no additional attributes, beyond those defined in the class pcimPolicy from which it is derived. Its role is to "tag" an instance of a class defined outside the realm of policy information as represented by PCIM as being nevertheless relevant to a policy specification. This tagging can potentially take place at two levels:
- Every instance to which pcimElementAuxClass is attached becomes an instance of the class pcimPolicy, since pcimElementAuxClass is a subclass of pcimPolicy. Searching for object class="pcimPolicy" will return the instance. (As noted earlier, this approach does NOT work for some directory implementations. To accommodate these implementations, policy-related entries SHOULD be tagged with the pcimKeyword "POLICY".) - With the pcimKeywords attribute that it inherits from pcimPolicy, an instance to which pcimElementAuxClass is attached can be tagged as being relevant to a particular type or category of policy information, using standard keywords, administrator-defined keywords, or both.The class definition is as follows:
( 1.3.6.1.1.6.1.17 NAME 'pcimElementAuxClass' DESC 'An auxiliary class used to tag instances of classes defined outside the realm of policy as relevant to a particular policy specification.' SUP pcimPolicy AUXILIARY )
5.14. The Three Policy Repository Classes
-
These classes provide a container for reusable policy information, such as reusable policy conditions and/or reusable policy actions. This document is concerned with mapping just the properties that appear in these classes. Conceptually, this may be thought of as a special location in the DIT where policy information may reside. Since pcimRepository is derived from the class dlm1AdminDomain defined in reference [6], this specification has a normative dependency on that element of reference [6] (as well as on its entire derivation hierarchy, which also appears in reference [6]). To maximize flexibility, the pcimRepository class is defined as abstract. A subclass pcimRepositoryAuxClass provides for auxiliary attachment to another entry, while a structural subclass pcimRepositoryInstance is available to represent a policy repository as a standalone entry.
The definition for the pcimRepository class is as follows:
( 1.3.6.1.1.6.1.18 NAME 'pcimRepository' DESC 'A container for reusable policy information.' SUP dlm1AdminDomain ABSTRACT MAY ( pcimRepositoryName ) )The pcimRepositoryName attribute is used to define a user-friendly name of this class, and may be used as a naming attribute if desired. It is defined as follows:
( 1.3.6.1.1.6.2.36 NAME 'pcimRepositoryName' DESC 'The user-friendly name of this policy repository.' EQUALITY caseIgnoreMatch ORDERING caseIgnoreOrderingMatch SUBSTR caseIgnoreSubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 SINGLE-VALUE )The two subclasses of pcimRepository are defined as follows. First, the pcimRepositoryAuxClass is an auxiliary class that can be used to aggregate reusable policy information. It is defined as follows:
( 1.3.6.1.1.6.1.19 NAME 'pcimRepositoryAuxClass' DESC 'An auxiliary class that can be used to aggregate reusable policy information.' SUP pcimRepository AUXILIARY )In cases where structural classes are needed instead of an auxiliary class, the pcimRepositoryInstance class is a structural class that can be used to aggregate reusable policy information. It is defined as follows:
( 1.3.6.1.1.6.1.20 NAME 'pcimRepositoryInstance' DESC 'A structural class that can be used to aggregate reusable policy information.' SUP pcimRepository STRUCTURAL )Three separate DIT structure rules could be written for this class. Each of these DIT structure rules would refer to a specific name form that enabled an instance of the pcimRepository class to be named under any superior using one of the three possible naming attributes (i.e., pcimRepositoryName, cn, and orderedCIMKeys). This structure rule SHOULD also include a superiorStructureRule (see Note 2 at the beginning of section 5).
5.15. The Auxiliary Class pcimSubtreesPtrAuxClass
-
This auxiliary class provides a single, multi-valued attribute that references a set of objects that are at the root of DIT subtrees containing policy-related information. By attaching this attribute to instances of various other classes, a policy administrator has a flexible way of providing an entry point into the directory that allows a client to locate and retrieve the policy information relevant to it.
It is intended that these entries are placed in the DIT such that well-known DNs can be used to reference a well-known structural entry that has the pcimSubtreesPtrAuxClass attached to it. In effect, this defines a set of entry points. Each of these entry points can contain and/or reference all related policy entries for any well-known policy domains. The pcimSubtreesPtrAuxClass functions as a tag to identify portions of the DIT that contain policy information.
This object does not provide the semantic linkages between individual policy objects, such as those between a policy group and the policy rules that belong to it. Its only role is to enable efficient bulk retrieval of policy-related objects, as described in Section 4.5.
Once the objects have been retrieved, a directory client can determine the semantic linkages by following references contained in multi-valued attributes, such as pcimRulesAuxContainedSet.
Since policy-related objects will often be included in the DIT subtree beneath an object to which this auxiliary class is attached, a client SHOULD request the policy-related objects from the subtree under the object with these references at the same time that it requests the references themselves.
Since clients are expected to behave in this way, the policy administrator SHOULD make sure that this subtree does not contain so many objects unrelated to policy that an initial search done in this way results in a performance problem. The pcimSubtreesPtrAuxClass SHOULD NOT be attached to the partition root for a large directory partition containing a relatively few number of policy-related objects along with a large number of objects unrelated to policy (again, "policy" here refers to the PCIM, not the X.501, definition and use of "policy"). A better approach would be to introduce a container object immediately below the partition root, attach pcimSubtreesPtrAuxClass to this container object, and then place all of the policy-related objects in that subtree.
The class definition is as follows:
( 1.3.6.1.1.6.1.21 NAME 'pcimSubtreesPtrAuxClass' DESC 'An auxiliary class providing DN references to roots of DIT subtrees containing policy-related objects.' SUP top AUXILIARY MAY ( pcimSubtreesAuxContainedSet ) )The attribute pcimSubtreesAuxContainedSet provides an unordered set of DN references to instances of one or more objects under which policy-related information is present. The objects referenced may or may not themselves contain policy-related information. The attribute definition is as follows:
( 1.3.6.1.1.6.2.37 NAME 'pcimSubtreesAuxContainedSet' DESC 'DNs of objects that serve as roots for DIT subtrees containing policy-related objects.' EQUALITY distinguishedNameMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.12 )Note that the cn attribute does NOT need to be defined for this class. This is because an auxiliary class is used as a means to collect common attributes and treat them as properties of an object. A good analogy is a #include file, except that since an auxiliary class is a class, all the benefits of a class (e.g., inheritance) can be applied to an auxiliary class.
5.16. The Auxiliary Class pcimGroupContainmentAuxClass
-
This auxiliary class provides a single, multi-valued attribute that references a set of pcimGroups. By attaching this attribute to instances of various other classes, a policy administrator has a flexible way of providing an entry point into the directory that allows a client to locate and retrieve the pcimGroups relevant to it.
As is the case with pcimRules, a policy administrator might have several different references to a pcimGroup in the overall directory structure. The pcimGroupContainmentAuxClass is the mechanism that makes it possible for the policy administrator to define all these different references.
The class definition is as follows:
( 1.3.6.1.1.6.1.22 NAME 'pcimGroupContainmentAuxClass' DESC 'An auxiliary class used to bind pcimGroups to an appropriate container object.' SUP top AUXILIARY MAY ( pcimGroupsAuxContainedSet ) )The attribute pcimGroupsAuxContainedSet provides an unordered set of references to instances of one or more pcimGroups associated with the instance of a structural class to which this attribute has been appended.
The attribute definition is as follows:
( 1.3.6.1.1.6.2.38 NAME 'pcimGroupsAuxContainedSet' DESC 'DNs of pcimGroups associated in some way with the instance to which this attribute has been appended.' EQUALITY distinguishedNameMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.12 )Note that the cn attribute does NOT have to be defined for this class for the same reasons as those given for the pcimSubtreesPtrAuxClass in section 5.15.
5.17. The Auxiliary Class pcimRuleContainmentAuxClass
-
This auxiliary class provides a single, multi-valued attribute that references a set of pcimRules. By attaching this attribute to instances of various other classes, a policy administrator has a flexible way of providing an entry point into the directory that allows a client to locate and retrieve the pcimRules relevant to it.
A policy administrator might have several different references to a pcimRule in the overall directory structure. For example, there might be references to all pcimRules for traffic originating in a particular subnet from a directory entry that represents that subnet. At the same time, there might be references to all pcimRules related to a particular DiffServ setting from an instance of a pcimGroup explicitly introduced as a container for DiffServ-related pcimRules. The pcimRuleContainmentAuxClass is the mechanism that makes it possible for the policy administrator to define all these separate references.
The class definition is as follows:
( 1.3.6.1.1.6.1.23 NAME 'pcimRuleContainmentAuxClass' DESC 'An auxiliary class used to bind pcimRules to an appropriate container object.' SUP top AUXILIARY MAY ( pcimRulesAuxContainedSet ) )The attribute pcimRulesAuxContainedSet provides an unordered set of references to one or more instances of pcimRules associated with the instance of a structural class to which this attribute has been appended. The attribute definition is as follows:
( 1.3.6.1.1.6.2.39 NAME 'pcimRulesAuxContainedSet' DESC 'DNs of pcimRules associated in some way with the instance to which this attribute has been appended.' EQUALITY distinguishedNameMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.12 )The cn attribute does NOT have to be defined for this class for the same reasons as those given for the pcimSubtreesPtrAuxClass in section 5.15.
6. Extending the Classes Defined in This Document
-
The following subsections provide general guidance on how to create a domain-specific schema derived from this document, discuss how the vendor classes in the PCLS should be used, and explain how policyTimePeriodConditions are related to other policy conditions.
6.1. Subclassing pcimConditionAuxClass and pcimActionAuxClass
-
In Section 4.4, there is a discussion of how, by representing policy conditions and policy actions as auxiliary classes in a schema, the flexibility is retained to instantiate a particular condition or action as either rule-specific or reusable. This flexibility is lost if a condition or action class is defined as structural rather than auxiliary. For standardized schemata, this document specifies that domain-specific information MUST be expressed in auxiliary subclasses of pcimConditionAuxClass and pcimActionAuxClass. It is RECOMMENDED that non-standardized schemata follow this practice as well.
6.2. Using the Vendor Policy Attributes
-
As discussed Section 5.9, the attributes pcimVendorConstraintData and pcimVendorConstraintEncoding are included in the pcimConditionVendorAuxClass to provide a mechanism for representing vendor-specific policy conditions that are not amenable to being represented with the pcimCondition class (or its subclasses). The attributes pcimVendorActionData and pcimVendorActionEncoding in the pcimActionVendorAuxClass class play the same role with respect to actions. This enables interoperability between different vendors who could not otherwise interoperate.
For example, imagine a network composed of access devices from vendor A, edge and core devices from vendor B, and a policy server from vendor C. It is desirable for this policy server to be able to configure and manage all of the devices from vendors A and B. Unfortunately, these devices will in general have little in common (e.g., different mechanisms, different ways for controlling those mechanisms, different operating systems, different commands, and so forth). The extension conditions provide a way for vendor-specific commands to be encoded as octet strings, so that a single policy server can commonly manage devices from different vendors.
6.3. Using Time Validity Periods
-
Time validity periods are defined as an auxiliary subclass of pcimConditionAuxClass, called pcimTPCAuxClass. This is to allow their inclusion in the AND/OR condition definitions for a pcimRule. Care should be taken not to subclass pcimTPCAuxClass to add domain-specific condition properties.
For example, it would be incorrect to add IPsec- or QoS-specific condition properties to the pcimTPCAuxClass class, just because IPsec or QoS includes time in its condition definition. The correct subclassing would be to create IPsec or QoS-specific subclasses of pcimConditionAuxClass and then combine instances of these domain-specific condition classes with the appropriate validity period criteria. This is accomplished using the AND/OR association capabilities for policy conditions in pcimRules.
7. Security Considerations
-
The PCLS, presented in this document, provides a mapping of the object-oriented model for describing policy information (PCIM) into a data model that forms the basic framework for describing the structure of policy data, in the case where the policy repository takes the form of an LDAP-accessible directory.
PCLS is not intended to represent any particular system design or implementation. PCLS is not directly useable in a real world system, without the discipline-specific mappings that are works in progress in the Policy Framework Working Group of the IETF.
These other derivative documents, which use PCIM and its discipline-specific extensions as a base, will need to convey more specific security considerations (refer to RFC 3060 for more information.)
The reason that PCLS, as defined here, is not representative of any real-world system, is that its object classes were designed to be independent of any specific discipline, or policy domain. For example, DiffServ and IPsec represent two different policy domains. Each document that extends PCIM to one of these domains will derive subclasses from the classes and relationships defined in PCIM, in order to represent extensions of a generic model to cover specific technical domains.
PCIM-derived documents will thus subclass the PCIM classes into classes specific to each technical policy domain (QOS, IPsec, etc.), which will, in turn, be mapped, to directory-specific schemata consistent with the PCLS documented here.
Even though discipline-specific security requirements are not appropriate for PCLS, specific security requirements MUST be defined for each operational real-world application of PCIM. Just as there will be a wide range of operational, real-world systems using PCIM, there will also be a wide range of security requirements for these systems. Some operational, real-world systems that are deployed using PCLS may have extensive security requirements that impact nearly all object classes utilized by such a system, while other systems' security requirements might have very little impact.
The derivative documents, discussed above, will create the context for applying operational, real-world, system-level security requirements against the various models that derive from PCIM, consistent with PCLS.
In some real-world scenarios, the values associated with certain properties, within certain instantiated object classes, may represent information associated with scarce, and/or costly (and therefore valuable) resources. It may be the case that these values must not be disclosed to, or manipulated by, unauthorized parties.
Since this document forms the basis for the representation of a policy data model in a specific format (an LDAP-accessible directory), it is herein appropriate to reference the data model-specific tools and mechanisms that are available for achieving the authentication and authorization implicit in a requirement that restricts read and/or read- write access to these values stored in a directory.
General LDAP security considerations apply, as documented in RFC 3377 [2]. LDAP-specific authentication and authorization tools and mechanisms are found in the following standards track documents, which are appropriate for application to the management of security applied to policy data models stored in an LDAP-accessible directory:
- RFC 2829 (Authentication Methods for LDAP) - RFC 2830 (Lightweight Directory Access Protocol (v3): Extension for Transport Layer Security)
Any identified security requirements that are not dealt with in the appropriate discipline-specific information model documents, or in this document, MUST be dealt with in the derivative data model documents which are specific to each discipline.
8. IANA Considerations
-
Refer to RFC 3383, "Internet Assigned Numbers Authority (IANA) Considerations for the Lightweight Directory Access Protocol (LDAP)" [16].
8.1. Object Identifiers
-
The IANA has registered an LDAP Object Identifier for use in this technical specification according to the following template:
Subject: Request for LDAP OID Registration Person & email address to contact for further information: Bob Moore (remoore@us.ibm.com) Specification: RFC 3703 Author/Change Controller: IESG Comments: The assigned OID will be used as a base for identifying a number of schema elements defined in this document.IANA has assigned an OID of 1.3.6.1.1.6 with the name of pcimSchema to this registration as recorded in the following registry:
http://www.iana.org/assignments/smi-numbers
8.2. Object Identifier Descriptors
-
The IANA has registered the LDAP Descriptors used in this technical specification as detailed in the following template:
Subject: Request for LDAP Descriptor Registration Update Descriptor (short name): see comment
Object Identifier: see commentPerson & email address to contact for further information: Bob Moore (remoore@us.ibm.com) Usage: see comment Specification: RFC 3703 Author/Change Controller: IESG Comments:The following descriptors have been added:
NAME Type OID -------------- ---- ------------ pcimPolicy O 1.3.6.1.1.6.1.1 pcimGroup O 1.3.6.1.1.6.1.2 pcimGroupAuxClass O 1.3.6.1.1.6.1.3 pcimGroupInstance O 1.3.6.1.1.6.1.4 pcimRule O 1.3.6.1.1.6.1.5 pcimRuleAuxClass O 1.3.6.1.1.6.1.6 pcimRuleInstance O 1.3.6.1.1.6.1.7 pcimRuleConditionAssociation O 1.3.6.1.1.6.1.8 pcimRuleValidityAssociation O 1.3.6.1.1.6.1.9 pcimRuleActionAssociation O 1.3.6.1.1.6.1.10 pcimConditionAuxClass O 1.3.6.1.1.6.1.11 pcimTPCAuxClass O 1.3.6.1.1.6.1.12 pcimConditionVendorAuxClass O 1.3.6.1.1.6.1.13 pcimActionAuxClass O 1.3.6.1.1.6.1.14 pcimActionVendorAuxClass O 1.3.6.1.1.6.1.15 pcimPolicyInstance O 1.3.6.1.1.6.1.16 pcimElementAuxClass O 1.3.6.1.1.6.1.17 pcimRepository O 1.3.6.1.1.6.1.18 pcimRepositoryAuxClass O 1.3.6.1.1.6.1.19 pcimRepositoryInstance O 1.3.6.1.1.6.1.20 pcimSubtreesPtrAuxClass O 1.3.6.1.1.6.1.21 pcimGroupContainmentAuxClass O 1.3.6.1.1.6.1.22 pcimRuleContainmentAuxClass O 1.3.6.1.1.6.1.23 pcimKeywords A 1.3.6.1.1.6.2.3 pcimGroupName A 1.3.6.1.1.6.2.4 pcimRuleName A 1.3.6.1.1.6.2.5 pcimRuleEnabled A 1.3.6.1.1.6.2.6 pcimRuleConditionListType A 1.3.6.1.1.6.2.7 pcimRuleConditionList A 1.3.6.1.1.6.2.8 pcimRuleActionList A 1.3.6.1.1.6.2.9 pcimRuleValidityPeriodList A 1.3.6.1.1.6.2.10 pcimRuleUsage A 1.3.6.1.1.6.2.11 pcimRulePriority A 1.3.6.1.1.6.2.12 pcimRuleMandatory A 1.3.6.1.1.6.2.13 pcimRuleSequencedActions A 1.3.6.1.1.6.2.14 pcimRoles A 1.3.6.1.1.6.2.15 pcimConditionGroupNumber A 1.3.6.1.1.6.2.16 NAME Type OID -------------- ---- ------------ pcimConditionNegated A 1.3.6.1.1.6.2.17 pcimConditionName A 1.3.6.1.1.6.2.18 pcimConditionDN A 1.3.6.1.1.6.2.19 pcimValidityConditionName A 1.3.6.1.1.6.2.20 pcimTimePeriodConditionDN A 1.3.6.1.1.6.2.21 pcimActionName A 1.3.6.1.1.6.2.22 pcimActionOrder A 1.3.6.1.1.6.2.23 pcimActionDN A 1.3.6.1.1.6.2.24 pcimTPCTime A 1.3.6.1.1.6.2.25 pcimTPCMonthOfYearMask A 1.3.6.1.1.6.2.26 pcimTPCDayOfMonthMask A 1.3.6.1.1.6.2.27 pcimTPCDayOfWeekMask A 1.3.6.1.1.6.2.28 pcimTPCTimeOfDayMask A 1.3.6.1.1.6.2.29 pcimTPCLocalOrUtcTime A 1.3.6.1.1.6.2.30 pcimVendorConstraintData A 1.3.6.1.1.6.2.31 pcimVendorConstraintEncoding A 1.3.6.1.1.6.2.32 pcimVendorActionData A 1.3.6.1.1.6.2.33 pcimVendorActionEncoding A 1.3.6.1.1.6.2.34 pcimPolicyInstanceName A 1.3.6.1.1.6.2.35 pcimRepositoryName A 1.3.6.1.1.6.2.36 pcimSubtreesAuxContainedSet A 1.3.6.1.1.6.2.37 pcimGroupsAuxContainedSet A 1.3.6.1.1.6.2.38 pcimRulesAuxContainedSet A 1.3.6.1.1.6.2.39
where Type A is Attribute, Type O is ObjectClass
These assignments are recorded in the following registry:
http://www.iana.org/assignments/ldap-parameters
9. Acknowledgments
-
We would like to thank Kurt Zeilenga, Roland Hedburg, and Steven Legg for doing a review of this document and making many helpful suggestions and corrections.
Several of the policy classes in this model first appeared in early IETF drafts on IPsec policy and QoS policy. The authors of these drafts were Partha Bhattacharya, Rob Adams, William Dixon, Roy Pereira, Raju Rajan, Jean-Christophe Martin, Sanjay Kamat, Michael See, Rajiv Chaudhury, Dinesh Verma, George Powers, and Raj Yavatkar.
This document is closely aligned with the work being done in the Distributed Management Task Force (DMTF) Policy and Networks working groups. We would especially like to thank Lee Rafalow, Glenn Waters, David Black, Michael Richardson, Mark Stevens, David Jones, Hugh Mahon, Yoram Snir, and Yoram Ramberg for their helpful comments.
10. Appendix: Constructing the Value of orderedCIMKeys
-
This appendix is non-normative, and is included in this document as a guide to implementers that wish to exchange information between CIM schemata and LDAP schemata.
Within a CIM name space, the naming is basically flat; all instances are identified by the values of their key properties, and each combination of key values must be unique. A limited form of hierarchical naming is available in CIM, however, by using weak associations: since a weak association involves propagation of key properties and their values from the superior object to the subordinate one, the subordinate object can be thought of as being named "under" the superior object. Once they have been propagated, however, propagated key properties and their values function in exactly the same way that native key properties and their values do in identifying a CIM instance.
The CIM mapping document [6] introduces a special attribute, orderedCIMKeys, to help map from the CIM_ManagedElement class to the LDAP class dlm1ManagedElement. This attribute SHOULD only be used in an environment where it is necessary to map between an LDAP-accessible directory and a CIM repository. For an LDAP environment, other LDAP naming attributes are defined (i.e., cn and a class-specific naming attribute) that SHOULD be used instead.
The role of orderedCIMKeys is to represent the information necessary to correlate an entry in an LDAP-accessible directory with an instance in a CIM name space. Depending on how naming of CIM-related entries is handled in an LDAP directory, the value of orderedCIMKeys represents one of two things:
- If the DIT hierarchy does not mirror the "weakness hierarchy" of the CIM name space, then orderedCIMKeys represents all the keys of the CIM instance, both native and propagated. - If the DIT hierarchy does mirror the "weakness hierarchy" of the CIM name space, then orderedCIMKeys may represent either all the keys of the instance, or only the native keys.Regardless of which of these alternatives is taken, the syntax of orderedCIMKeys is the same - a DirectoryString of the form
<className>.<key>=<value>[,<key>=<value>]*
where the <key>=<value> elements are ordered by the names of the key properties, according to the collating sequence for US ASCII. The only spaces allowed in the DirectoryString are those that fall within a <value> element. As with alphabetizing the key properties, the goal of suppressing the spaces is once again to make the results of string operations predictable.
The values of the <value> elements are derived from the various CIM syntaxes according to a grammar specified in [5].
11. References
11.1. Normative References
-
[1] Moore, B., Ellesson,E., Strassner, J. and A. Westerinen "Policy Core Information Model -- Version 1 Specification", RFC 3060, February 2001. [2] Hodges, J. and R. Morgan, "Lightweight Directory Access Protocol (v3): Technical Specification", RFC 3377, September 2002. [3] Wahl, M., Coulbeck, A., Howes,T. and S. Kille, "Lightweight Directory Access Protocol (v3): Attribute Syntax Definitions", RFC 2252, December 1997. [4] The Directory: Models. ITU-T Recommendation X.501, 2001. [5] Distributed Management Task Force, Inc., "Common Information Model (CIM) Specification", Version 2.2, June 14, 1999. This document is available on the following DMTF web page: http://www.dmtf.org/standards/documents/CIM/DSP0004.pdf [6] Distributed Management Task Force, Inc., "DMTF LDAP Schema for the CIM v2.5 Core Information Model", April 15, 2002. This document is available on the following DMTF web page: http://www.dmtf.org/standards/documents/DEN/DSP0123.pdf [7] Wahl, M., "A Summary of the X.500(96) User Schema for use with LDAPv3", RFC 2256, December 1997. [8] The Directory: Selected Attribute Types. ITU-T Recommendation X.520, 2001. [9] Zeilenga, K., Ed., "Lightweight Directory Access Protocol (LDAP): Additional Matching Rules", RFC 3698, February 2004. [10] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
11.2. Informative References
-
[11] Hovey, R. and S. Bradner, "The Organizations Involved in the IETF Standards Process", BCP 11, RFC 2028, October 1996. [12] Strassner, J., policy architecture BOF presentation, 42nd IETF Meeting, Chicago, Illinois, October 1998. Minutes of this BOF are available at the following location: http://www.ietf.org/proceedings/98aug/index.html. [13] Yavatkar, R., Guerin, R. and D. Pendarakis, "A Framework for Policy-based Admission Control", RFC 2753, January 2000. [14] Wahl, M., Alvestrand, H., Hodges, J. and R. Morgan, "Authentication Methods for LDAP", RFC 2829, May 2000 [15] Hodges, J., Morgan, R. and M. Wahl, "Lightweight Directory Access Protocol (v3): Extension for Transport Layer Security", RFC 2830, May 2000. [16] Zeilenga, K., "Internet Assigned Numbers Authority (IANA) Considerations for the Lightweight Directory Access Protocol (LDAP)", BCP 64, RFC 3383, September 2002.
12. Authors' Addresses
-
John Strassner Intelliden Corporation 90 South Cascade Avenue Colorado Springs, CO 80903 Phone: +1.719.785.0648 Fax: +1.719.785.0644 EMail: john.strassner@intelliden.com Bob Moore IBM Corporation P. O. Box 12195, BRQA/B501/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
Ryan Moats
Lemur Networks, Inc.
15621 Drexel Circle
Omaha, NE 68135Phone: +1-402-894-9456 EMail: rmoats@lemurnetworks.net
Ed Ellesson
3026 Carriage Trail
Hillsborough, NC 27278Phone: +1 919-644-3977 EMail: ellesson@mindspring.com
13. Full Copyright Statement
-
Copyright © The Internet Society (2004). This document is subject to the rights, licenses and restrictions contained in BCP 78 and except as set forth therein, the authors retain all their rights.
This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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.
Intellectual Property
-
The IETF takes no position regarding the validity or scope of any Intellectual Property Rights 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; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat 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 on-line IPR repository at http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org.
Acknowledgement
-
Funding for the RFC Editor function is currently provided by the Internet Society.