Network Working Group K. Zeilenga
Request for Comments: 3671 OpenLDAP Foundation
Category: Standards Track December 2003
Collective Attributes in
the Lightweight Directory Access Protocol (LDAP)
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
X.500 collective attributes allow common characteristics to be shared
between collections of entries. This document summarizes the X.500
information model for collective attributes and describes use of
collective attributes in LDAP (Lightweight Directory Access
Protocol). This document provides schema definitions for collective
attributes for use in LDAP.
1. Introduction
In X.500 [X.500], a collective attribute is "a user attribute whose
values are the same for each member of an entry collection" [X.501].
This document details their use in the Lightweight Directory Access
Protocol (LDAP) [RFC3377].
1.1. Entry Collections
A collection of entries is a grouping of object and alias entries
based upon common properties or shared relationship between the
corresponding entries which share certain attributes. An entry
collection consists of all entries within scope of a collective
attributes subentry [RFC3672]. An entry can belong to several entry
collections.
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RFC 3671 Collective Attributes in LDAP December 2003
1.2. Collective Attributes
Attributes shared by the entries comprising an entry collection are
called collective attributes. Values of collective attributes are
visible but not updateable to clients accessing entries within the
collection. Collective attributes are updated (i.e., modified) via
their associated collective attributes subentry.
When an entry belongs to multiple entry collections, the entry's
values of each collective attribute are combined such that
independent sources of these values are not manifested to clients.
Entries can specifically exclude a particular collective attribute by
listing the attribute as a value of the collectiveExclusions
attribute. Like other user attributes, collective attributes are
subject to a variety of controls including access, administrative,
and content controls.
1.3. Conventions
Schema definitions are provided using LDAPv3 [RFC2251] description
formats [RFC2252]. Definitions provided here are formatted (line
wrapped) for readability.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14 [RFC2119].
2. System Schema for Collective Attributes
The following operational attributes are used to manage Collective
Attributes. LDAP servers [RFC3377] MUST act in accordance with the
X.500 Directory Models [X.501] when providing this service.
2.1. collectiveAttributeSubentry
Subentries of this object class are used to administer collective
attributes and are referred to as collective attribute subentries.
( 2.5.17.2 NAME 'collectiveAttributeSubentry' AUXILIARY )
A collective attribute subentry SHOULD contain at least one
collective attribute. The collective attributes contained within a
collective attribute subentry are available for finding, searching,
and comparison at every entry within the scope of the subentry. The
collective attributes, however, are administered (e.g., modified) via
the subentry.
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Implementations of this specification SHOULD support collective
attribute subentries in both collectiveAttributeSpecificArea
(2.5.23.5) and collectiveAttributeInnerArea (2.5.23.6) administrative
areas [RFC3672][X.501].
2.2. collectiveAttributeSubentries
The collectiveAttributeSubentries operational attribute identifies
all collective attribute subentries that affect the entry.
( 2.5.18.12 NAME 'collectiveAttributeSubentries'
EQUALITY distinguishedNameMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.12
USAGE directoryOperation NO-USER-MODIFICATION )
2.3. collectiveExclusions
The collectiveExclusions operational attribute allows particular
collective attributes to be excluded from an entry. It MAY appear in
any entry and MAY have multiple values.
( 2.5.18.7 NAME 'collectiveExclusions'
EQUALITY objectIdentifierMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.38
USAGE directoryOperation )
The descriptor excludeAllCollectiveAttributes is associated with the
OID 2.5.18.0. When this descriptor or OID is present as a value of
the collectiveExclusions attribute, all collective attributes are
excluded from an entry.
3. Collective Attribute Types
A userApplications attribute type can be defined to be COLLECTIVE
[RFC2252]. This indicates that the same attribute values will appear
in the entries of an entry collection subject to the use of the
collectiveExclusions attribute and other administrative controls.
These administrative controls MAY include DIT Content Rules, if
implemented.
Collective attribute types are commonly defined as subtypes of non-
collective attribute types. By convention, collective attributes are
named by prefixing the name of their non-collective supertype with
"c-". For example, the collective telephone attribute is named
c-TelephoneNumber after its non-collective supertype telephoneNumber.
Non-collective attributes types SHALL NOT subtype collective
attributes.
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Collective attributes SHALL NOT be SINGLE-VALUED. Collective
attribute types SHALL NOT appear in the attribute types of an object
class definition.
Operational attributes SHALL NOT be defined to be collective.
The remainder of section provides a summary of collective attributes
derived from those defined in [X.520]. The SUPerior attribute types
are described in [RFC 2256] for use with LDAP.
Implementations of this specification SHOULD support the following
collective attributes and MAY support additional collective
attributes.
3.1. Collective Locality Name
The c-l attribute type specifies a locality name for a collection of
entries.
( 2.5.4.7.1 NAME 'c-l'
SUP l COLLECTIVE )
3.2. Collective State or Province Name
The c-st attribute type specifies a state or province name for a
collection of entries.
( 2.5.4.8.1 NAME 'c-st'
SUP st COLLECTIVE )
3.3. Collective Street Address
The c-street attribute type specifies a street address for a
collection of entries.
( 2.5.4.9.1 NAME 'c-street'
SUP street COLLECTIVE )
3.4. Collective Organization Name
The c-o attribute type specifies an organization name for a
collection of entries.
( 2.5.4.10.1 NAME 'c-o'
SUP o COLLECTIVE )
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RFC 3671 Collective Attributes in LDAP December 2003
3.5. Collective Organizational Unit Name
The c-ou attribute type specifies an organizational unit name for a
collection of entries.
( 2.5.4.11.1 NAME 'c-ou'
SUP ou COLLECTIVE )
3.6. Collective Postal Address
The c-PostalAddress attribute type specifies a postal address for a
collection of entries.
( 2.5.4.16.1 NAME 'c-PostalAddress'
SUP postalAddress COLLECTIVE )
3.7. Collective Postal Code
The c-PostalCode attribute type specifies a postal code for a
collection of entries.
( 2.5.4.17.1 NAME 'c-PostalCode'
SUP postalCode COLLECTIVE )
3.8. Collective Post Office Box
The c-PostOfficeBox attribute type specifies a post office box for a
collection of entries.
( 2.5.4.18.1 NAME 'c-PostOfficeBox'
SUP postOfficeBox COLLECTIVE )
3.9. Collective Physical Delivery Office Name
The c-PhysicalDeliveryOfficeName attribute type specifies a physical
delivery office name for a collection of entries.
( 2.5.4.19.1 NAME 'c-PhysicalDeliveryOfficeName'
SUP physicalDeliveryOfficeName COLLECTIVE )
3.10. Collective Telephone Number
The c-TelephoneNumber attribute type specifies a telephone number for
a collection of entries.
( 2.5.4.20.1 NAME 'c-TelephoneNumber'
SUP telephoneNumber COLLECTIVE )
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3.11. Collective Telex Number
The c-TelexNumber attribute type specifies a telex number for a
collection of entries.
( 2.5.4.21.1 NAME 'c-TelexNumber'
SUP telexNumber COLLECTIVE )
3.13. Collective Facsimile Telephone Number
The c-FacsimileTelephoneNumber attribute type specifies a facsimile
telephone number for a collection of entries.
( 2.5.4.23.1 NAME 'c-FacsimileTelephoneNumber'
SUP facsimileTelephoneNumber COLLECTIVE )
3.14. Collective International ISDN Number
The c-InternationalISDNNumber attribute type specifies an
international ISDN number for a collection of entries.
( 2.5.4.25.1 NAME 'c-InternationalISDNNumber'
SUP internationalISDNNumber COLLECTIVE )
4. Security Considerations
Collective attributes, like other attributes, are subject to access
control restrictions and other administrative policy. Generally
speaking, collective attributes accessed via an entry in a collection
are governed by rules restricting access to attributes of that entry.
And collective attributes access via a subentry are governed by rules
restricting access to attributes of that subentry. However, as LDAP
does not have a standard access model, the particulars of each
server's access control system may differ.
General LDAP security considerations [RFC3377] also apply.
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5. IANA Considerations
The IANA has registered the LDAP descriptors [RFC3383] defined in
this technical specification. The following registration template is
suggested:
Subject: Request for LDAP Descriptor Registration
Descriptor see comments
Object Identifier: see comment
Person & email address to contact for further information:
Kurt Zeilenga <kurt@OpenLDAP.org>
Usage: see comment
Specification: RFC3671
Author/Change Controller: IESG
Comments:
NAME Type OID
------------------------ ---- -----------------
c-FacsimileTelephoneNumber A 2.5.4.23.1
c-InternationalISDNNumber A 2.5.4.25.1
c-PhysicalDeliveryOffice A 2.5.4.19.1
c-PostOfficeBox A 2.5.4.18.1
c-PostalAddress A 2.5.4.16.1
c-PostalCode A 2.5.4.17.1
c-TelephoneNumber A 2.5.4.20.1
c-TelexNumber A 2.5.4.21.1
c-l A 2.5.4.7.1
c-o A 2.5.4.10.1
c-ou A 2.5.4.11.1
c-st A 2.5.4.8.1
c-street A 2.5.4.9.1
collectiveAttributeSubentries A 2.5.18.12
collectiveAttributeSubentry O 2.5.17.2
collectiveExclusions A 2.5.18.7
where Type A is Attribute and Type O is ObjectClass.
The Object Identifiers used in this document were assigned by the
ISO/IEC Joint Technical Committee 1 - Subcommittee 6 to identify
elements of X.500 schema [X.520]. This document make no OID
assignments, it only provides LDAP schema descriptions with existing
elements of X.500 schema.
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6. Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances of
licenses to be made available, or the result of an attempt made to
obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification can
be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.
7. Acknowledgments
This document is based upon the ITU Recommendations for the Directory
[X.501][X.520].
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2251] Wahl, M., Howes, T. and S. Kille, "Lightweight Directory
Access Protocol (v3)", RFC 2251, December 1997.
[RFC2252] Wahl, M., Coulbeck, A., Howes, T. and S. Kille,
"Lightweight Directory Access Protocol (v3): Attribute
Syntax Definitions", RFC 2252, December 1997.
[RFC2256] Wahl, M., "A Summary of the X.500(96) User Schema for use
with LDAPv3", RFC 2256, December 1997.
[RFC3377] Hodges, J. and R. L. Morgan, "Lightweight Directory Access
Protocol (v3): Technical Specification", RFC 3377,
September 2002.
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[RFC3383] Zeilenga, K., "Internet Assigned Numbers Authority (IANA)
Considerations for the Lightweight Directory Access
Protocol (LDAP)", BCP 64, RFC 3383, September 2002.
[RFC3672] Zeilenga, K. and S. Legg, "Subentries in Lightweight
Directory Access Protocol (LDAP)", RFC 3672, December
2003.
[X.501] "The Directory: Models", ITU-T Recommendation X.501, 1993.
8.2. Informative References
[X.500] "The Directory: Overview of Concepts, Models", ITU-T
Recommendation X.500, 1993.
[X.520] "The Directory: Selected Attribute Types", ITU-T
Recommendation X.520, 1993.
9. Author's Address
Kurt D. Zeilenga
OpenLDAP Foundation
EMail: Kurt@OpenLDAP.org
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10. Full Copyright Statement
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Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
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