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X.500 URI Attribute Types and Object Class                   Mark





Network Working Group                                          M. Smith
INTERNET-DRAFT                                   University of Michigan
                                                        11 October 1995
Request for Comments: 2079                      Netscape Communications
Category: Standards Track                                  January 1997


   Definition of an X.500 Attribute Types Type and an Object Class to Hold
                  Uniform Resource Identifiers (URIs)
               Filename: draft-ietf-asid-x500-url-02.txt

Status of this Memo

   This document is specifies an Internet-Draft.  Internet-Drafts are working
   documents of Internet standards track protocol for the
   Internet Engineering Task Force (IETF), its
   areas, community, and its working groups.  Note that other groups may also
   distribute working documents as Internet-Drafts.

   Internet-Drafts are draft documents valid for a maximum of six
   months requests discussion and may be updated, replaced, or obsoleted by other
   documents at any time.  It is inappropriate to use Internet-
   Drafts as reference material or suggestions for
   improvements.  Please refer to cite them other than as
   ``work in progress.''

   To learn the current status edition of any Internet-Draft, please check
   the ``1id-abstracts.txt'' listing contained in the Internet-
   Drafts Shadow Directories on ds.internic.net (US East Coast),
   nic.nordu.net (Europe), ftp.isi.edu (US West Coast), or
   munnari.oz.au (Pacific Rim). "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.  Editorial comments should be
   sent to the author (mcs@umich.edu).  Technical discussion will take
   place on the IETF ASID mailing list (ietf-asid@umich.edu).

   This Internet Draft expires April 11, 1995.

Abstract

   Uniform Resource Locators (URLs) are being widely used to specify the
   location of Internet resources.  There is an urgent need to be able
   to include URLs in directories that conform to the LDAP and X.500 directory,
   information models, and a desire to include other types of Uniform
   Resource Identifiers (URIs) as they are defined.  A number of
   independent groups are already experimenting with the inclusion of
   URLs in the LDAP and X.500 directory. directories.  This document builds on the
   experimentation to date and defines two a new attribute types type and an
   auxiliary object class to allow URIs, including URLs, to be stored in
   directory entries in a standard way.






Smith                   IETF ASID Working Group                 [Page 1]

INTERNET-DRAFT    URI Attribute Types and Object Class   11 October 1995

Background and Intended Usage

   Uniform Resource Locators (URLs) as defined by [1] are the first of
   several types of Uniform Resource Identifiers (URIs) being defined by
   the IETF.  URIs are widely used on the Internet, most notably within
   Hypertext Markup Language [2] documents. This document defines two an
   X.500 [2,3] [3,4] attribute types
   (labeledURI and labeledURL) type called labeledURI and an auxiliary object
   class
   (labeledURIObject) called labeledURIObject to hold all types of URIs, including
   URLs.  It is
   assumed that as other kinds of URIs  These definitions are defined, additional attribute
   types may be created to support storing them in directory entries.

   The rationale for adding separate attribute types designed for the different
   kinds of URIs is to support efficient programmatic access to specific
   types of URIs.  For example, if an indexing service is only
   interested in URLs, having them available use in their own attribute
   makes pulling them out of a directory entry straightforward LDAP and
   efficient.

   It is intended that the schema elements defined in this document will
   be progressed according to the process defined by the Internet X.500
   Schema Working Group [4].
   directories, and may be used in other contexts as well.












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RFC 2079          URI Attribute Type and Object Class       January 1997


Schema Definition of the labeledURL labeledURI Attribute Type

   Name:             labeledURL             labeledURI
   ShortName:        None
   Description:      Uniform Resource Locator Identifier with optional label
   OID:              umichAttributeType.41 (1.3.6.1.4.1.250.1.41)              umichAttributeType.57 (1.3.6.1.4.1.250.1.57)
   Syntax:           caseExactString
   SizeRestriction:  None
   SingleValued:     False

Discussion of the labeledURL labeledURI Attribute Type

   The labeledURL labeledURI attribute type has the caseExactString syntax (since
   URLs
   URIs are case-sensitive) and it is multivalued.  Values placed in the
   attribute should consist of a URL as defined in [1] URI (at the present time, a URL)
   optionally followed by one or more space characters and a label.
   Since space characters are not allowed to appear un-encoded in URLs, URIs,
   there is no ambiguity about where the label begins.  At the present
   time, the URI portion must comply with the URL specification [1].
   Multiple labeledURL labeledURI values will generally indicate different
   resources that are all related to the X.500 object, but may indicate
   different locations for the same resource.







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INTERNET-DRAFT    URI Attribute Types and Object Class   11 October 1995

   The label is used to describe the resource to which the URL URI points,
   and is intended as a friendly name fit for human consumption.  This
   document does not propose any specific syntax for the label part.
   Note that in  In
   some cases it may be helpful to include in the label some indication
   of the kind and/or size of the resource referenced by the URL. URI.

   Note that the label may include any characters allowed by the
   caseExactString syntax, but that the use of non-IA5 (non-ASCII)
   characters is discouraged as not all directory clients may handle
   them in the same manner.

   Some examples of valid labeledURL values (the first does  If non-IA5 characters are included, they
   should be represented using the X.500 conventions, not have the HTML
   conventions (e.g., the character that is an "a" with a
   label):

     ftp://ds.internic.net/rfc/rfc822.txt

     http://www.umich.edu/ University of Michigan Home Page

     http://champagne.inria.fr/Unites/rennes.gif Rennes [photo]


Schema Definition of ring above it
   should be encoded using the T.61 sequence 0xCA followed by an "a"
   character; do not use the HTML escape sequence "&aring").

Examples of labeledURI Attribute Type

   Name:             labeledURI
   ShortName:        None
   Description:      Uniform Resource Identifier with optional label
   OID:              umichAttributeType.57 (1.3.6.1.4.1.250.1.57)
   Syntax:           caseExactString
   SizeRestriction:  None
   SingleValued:     False


Discussion Values

   An example of the a labeledURI attribute value that does not include a
   label:

                   ftp://ds.internic.net/rfc/rfc822.txt







Smith                       Standards Track                     [Page 2]

RFC 2079          URI Attribute Type

   The labeledURI attribute type has the caseExactString syntax (since
   URIs are case-sensitive) and it is multivalued.  Values placed in the
   attribute should consist Object Class       January 1997


   An example of a URI (at labeledURI attribute value that contains a tilde
   character in the present time, URL (special characters in a URL)
   optionally followed URL must be encoded as
   specified by the URL document [1]).  The label is "LDAP Home Page":

             http://www.umich.edu/%7Ersug/ldap/ LDAP Home Page

   Another example.  This one or more space characters and includes a label.
   Since space characters are not allowed to appear un-encoded hint in URIs,
   there is no ambiguity about where the label begins.  At the present
   time, to help the URI portion must comply with
   user realize that the URL specification [1].
   Multiple labeledURI values will generally indicate different
   resources that are all related points to a photo image.

        http://champagne.inria.fr/Unites/rennes.gif Rennes [photo]

Schema Definition of the X.500 object, but may indicate
   different locations for labeledURIObject Object Class

   Name:              labeledURIObject
   Description:       object that contains the same resource.






Smith                   IETF ASID Working Group                 [Page 3]

INTERNET-DRAFT URI Attribute Types and attribute type
   OID:               umichObjectClass.15 (1.3.6.1.4.1.250.3.15)
   SubclassOf:        top
   MustContain:
   MayContain:        labeledURI

Discussion of the labeledURIObject Object Class   11 October 1995

   The label labeledURIObject class is used to describe the resource to which the URI points, a subclass of top and may contain the
   labeledURI attribute.  The intent is intended as a friendly name fit that this object class can be
   added to existing directory objects to allow for human consumption. inclusion of URI
   values.  This
   document approach does not propose any specific syntax for preclude including the label part.
   Note that labeledURI
   attribute type directly in some cases it may be helpful to include other object classes as appropriate.

Security Considerations

   Security considerations are not discussed in the label
   some indication of the kind and/or size of the resource referenced by
   the URI.

   Note this memo, except to
   note that blindly inserting the label may include any characters allowed by the
   caseExactString syntax, but that the use portion of non-IA5 (non-ASCII)
   characters a labeledURI
   attribute value into an HTML document is discouraged as not all directory clients recommended, as this may handle
   them
   allow a malicious individual to include HTML tags in the same manner.


Schema Definition label that
   mislead viewers of the labeledURIObject Object Class

   Name:              labeledURIObject
   Description:       object that contains entire document in which the labeledURI value
   was inserted.

Acknowledgments

   Paul-Andre Pays, Martijn Koster, Tim Howes, Rakesh Patel, Russ
   Wright, and Hallvard Furuseth provided invaluable assistance in the URI attribute types
   OID:               umichObjectClass.15 (1.3.6.1.4.1.250.3.15)
   SubclassOf:        top
   MustContain:
   MayContain:        labeledURI, labeledURL


Discussion
   creation of this document.

   This material is based in part upon work supported by the labeledURIObject National
   Science Foundation under Grant No. NCR-9416667.






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RFC 2079          URI Attribute Type and Object Class       January 1997


Appendix:  The labeledURIObject class labeledURL Attribute Type (Deprecated)

   An earlier draft of this document defined an additional attribute
   type called labeledURL.  This attribute type is deprecated, and
   should not be used when adding new values to directory entries.  The
   original motivation for including a subclass separate attribute type to hold
   URLs was that this would better enable efficient progammatic access
   to specific types of top and may contain URIs.  After some deliberation, the
   labeledURI and labeledURL attributes. IETF-ASID
   working group concluded that it was better to simply have one
   attribute than two.

   The intent schema definition for labeledURL is that included here for historical
   reference only.  Directory client software may want to support this object
   class can be added
   schema definition (in addition to existing directory objects labeledURI) to allow for
   inclusion of URI values.  This approach does not preclude including ease the labeledURI and transition
   away from labeledURL attribute types directly in other
   object classes as appropriate. for those sites that are using it.

   Name:             labeledURL
   ShortName:        None
   Description:      Uniform Resource Locator with optional label
   OID:              umichAttributeType.41 (1.3.6.1.4.1.250.1.41)
   Syntax:           caseExactString
   SizeRestriction:  None
   SingleValued:     False
   OID:              umichAttributeType.41 (1.3.6.1.4.1.250.1.41)

References

   [1] Berners-Lee, T., Masinter, L., and M. McCahill, M., "Uniform
   Resource Locators (URL)", RFC 1738, CERN, Xerox Corporation,
   University of Minnesota, December 1994, 1994.
   <URL:ftp://ds.internic.net/rfc/rfc1738.txt>

   [2] Berners-Lee, T., and D. Connolly, "Hypertext Markup Language -
   2.0", RFC 1866, <URL:ftp://ds.internic.net/rfc/rfc1866.txt>

   [3] The Directory: Overview of Concepts, Models and Service.  CCITT
   Recommendation X.500, 1988.

   [3]

   [4] Information Processing Systems -- Open Systems Interconnection --
   The Directory: Overview of Concepts, Models and Service.  ISO/IEC JTC
   1/SC21; International Standard 9594-1, 1988.










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INTERNET-DRAFT

RFC 2079          URI Attribute Types Type and Object Class   11 October 1995


   [4] Howes, T., Rossen, K., Sataluri, S., and Wright, R., "Procedures
   for Formalizing, Evolving, and Maintaining the Internet X.500
   Directory Schema", Internet Draft (Work In Progress) of the Schema
   Working Group, <URL:ftp://ds.internic.net/internet-drafts/
   draft-howes-x500-schema-03.txt>


Security Considerations

   Security considerations are not discussed in this memo.


Acknowledgments

   Paul-Andre Pays, Martijn Koster, Tim Howes, Rakesh Patel, and Russ
   Wright provided invaluable assistance in the creation of this
   document.

   This material is based upon work supported by the National Science
   Foundation under Grant No. NCR-9416667.       January 1997


Author's Address

   Mark Smith
   University of Michigan
   Information Technology Division
   535 W. William St.
   Ann Arbor, MI 48103-4943,
   Netscape Communications Corp.
   501 E. Middlefield Rd.
   Mountain View, CA 94043, USA

   Phone:  +1 313 764-2277
   Fax:    +1 313 765-5140 415 937-3477
   EMail:  mcs@umich.edu

                This Internet Draft expires April 11, 1995.  mcs@netscape.com










































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