RFC 3061 INFORMATIONAL URN · IDENTIFIERS · NAMING

A URN Namespace of Object Identifiers

A standard way to write Object Identifiers as Uniform Resource Names.

On rfc-editor.org ↗
PUBLISHED
February 2001
AUTHORS
M. Mealling
STREAM
INDEPENDENT
BUILDS ON
RFC 3001 — A URN Namespace of Object Identifiers
NAMESPACE IDENTIFIER
oid
ALLOWED CHARACTERS
Digits 0-9 and period
RESOLUTION MECHANISM
None defined
DOI
10.17487/RFC3061
ERRATA
Reported errata

RFC text

Contents
Original text · RFC Editor View on rfc-editor.org ↗
Network Working Group                                        M. Mealling
Request for Comments: 3061                                      Verisign
Category: Informational                                    February 2001
Obsoletes: 3001


                 A URN Namespace of Object Identifiers

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

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

Abstract

   This document describes a Uniform Resource Name (URN) namespace that
   contains Object Identifiers (OIDs).  It obsoletes RFC 3001.

1. Introduction

   An Object Identifier is a tree of nodes where each node is simply a
   sequence of digits.  The rules roughly state that once an entity is
   assigned a node in the Object Identifier (OID) tree, it has sole
   discretion to further subdelegate sub-trees off of that node. Some
   examples of OIDs include:

   o  1.3.6.1 - the Internet OID
   o  1.3.6.1.4.1 - IANA-assigned company OIDs, used for private MIBs
      and such things
   o  1.3.6.1.2.1.27 - The Applications MIB
   o  0.9.2342.19200300.100.4 - Object ID's used in the directory pilot
      project to identify X.500 Object Classes.  Mostly defined in RFC
      1274.

   This document specifies the "oid" URN namespace [2].  This namespace
   is for encoding an Object Identifier as specified in ASN.1 [3] as a
   URI.  RFC 3001 [1] is obsoleted by this specification.

   The namespace specification is for a formal namespace.

2. Specification Template

   Namespace ID:

      "oid" requested.

   Registration Information:

       Registration Version Number: 1
       Registration Date: 2000-04-30

   Declared registrant of the namespace:

      The ISO/IEC Joint Technical Committee 1 - SubCommittee 6

         The real authority is the ASN.1 specification itself but SC6 is
         the committee that has the authority to interpret what that
         means, thus that committee is listed as the registrant.

   Declaration of structure:

      The NSS portion of the identifier is based on the string encoding
      rules found in RFC 1778 Section 2.15 [4] which specifies a series
      of digits separated by a period with the most significant digit
      being at the left and the least significant being at the right.
      At no time shall the NSS portion of the URN contain the human
      readable description of a particular node in the OID tree.  The
      NSS portion of the name is strictly limited to the digits 0-9 and
      the '.' character with no leading zeros. No other characters are
      permitted. This is all expressed in the following ABNF:

           oid             = number *( DOT number )
           number          = DIGIT / ( LEADDIGIT 1*DIGIT )
           LEADDIGIT       = %x31-39 ; 1-9
           DIGIT           = %x30 / LEADDIGIT ; 0-9
           DOT             = %x2E ; period

      No changes are anticipated since Object Identifiers are fairly
      simple and have been standardized with no changes for many years.

   Relevant ancillary documentation:

      Relevant documentation can be found in X.660/Amd 2 | ISO/IEC
      9834-1/Amd 2[3].

   Identifier uniqueness considerations:

      The rules for assignment of OIDs requires that each OID be unique
      to the OID space and that it cannot be reassigned or reused.  By
      reference this URN namespace inherents those rules.

   Identifier persistence considerations:

      The rules concerning the use of OIDs requires that they not be
      reused once assigned.  By reference this URN namespace inherents
      those rules.

   Process of identifier assignment:

      Once an OID is assigned to some entity, that entity can then
      create and assign new OIDs below that particular OID.  There are
      multiple entities that assign new OIDs to the general public.  The
      top three levels are pre-assigned as follows:

         0 - ITU-T assigned
         1 - ISO assigned
         2 - Joint ISO/ITU-T assignment

      several assigned OIDs that are of importance to the Internet are:

         1.3.6.1 - the Internet OID
         1.3.6.1.4.1 - IANA-assigned company OIDs, used for private
         MIBs and such things

   Process of identifier resolution:

      At this time no resolution mechanism is defined.

   Rules for Lexical Equivalence:

      OIDs are composed of multiple occurrences of digits and the "."
      character.  Lexical equivalence is achieved by exact string match.

   Conformance with URN Syntax:

      There are no additional characters reserved.

   Validation mechanism:

      None.

   Scope:

      Global

3. Examples

   The following examples are taken from the example OIDs from the
   Introduction:

      urn:oid:1.3.6.1
      urn:oid:1.3.6.1.4.1
      urn:oid:1.3.6.1.2.1.27
      URN:OID:0.9.2342.19200300.100.4

4. Security Considerations

   None not already inherent to using unverifiable OIDs.

5. Acknowledgements

   The author would like to thank Harald Alvestrand for the use of his
   OID database as a source for examples and references.

References

   [1]  Mealling, M., "A URN Namespace of Object Identifiers", RFC 3001,
        November 2000.

   [2]  Moats, R., "URN Syntax", RFC 2141, May 1997.

   [3]  CCITT, "Specification of Basic Encoding Rules for Abstract
        Syntax Notation One (ASN.1)", CCITT Recommendation X.209,
        January 1988.

   [4]  Howes, T., Kille, S., Yeong, W. and C. Robbins, "The String
        Representation of Standard Attribute Syntaxes", RFC 1778, March
        1995.

Author's Address

   Michael Mealling
   Verisign
   505 Huntmar Park Drive
   Herndon, VA  22070
   US

   Phone: +1 770 935 5492
   EMail: michaelm@netsol.com
   URI:   http://www.netsol.com

Full Copyright Statement

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

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
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   followed, or as required to translate it into languages other than
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   The limited permissions granted above are perpetual and will not be
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   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
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Acknowledgement

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

ISO Plain Language

On this page
PROBLEMObject Identifiers are dotted sequences of numbers, and this memo defines how to represent them in the Uniform Resource Name system.
MECHANISMThe registered namespace identifier is oid. The name contains the OID digits separated by periods, with no leading zeroes in a number.
WHY IT MATTERSThe form urn:oid:1.3.6.1 names an OID, but RFC 3061 defines no lookup or validation service. It obsoletes RFC 3001.

§1Putting an Object Identifier in a URN

An Object Identifier (OID) is a sequence of numbered branches in a tree. Once an entity receives a branch, it can assign branches below it under the OID rules.

RFC 3061 registers the namespace identifier oid so an OID can be written as a Uniform Resource Name (URN). Examples in the memo include urn:oid:1.3.6.1 and urn:oid:1.3.6.1.4.1.

An OID is a path of numbers in an identifier tree. Add the urn:oid: prefix to write that path as a URN.

§2The Characters and Number Rules

The part after urn:oid: contains digits from 0 to 9 with periods between numbers. It must not contain a human-readable label, and a number cannot have leading zeroes.

The memo defines lexical equivalence as an exact string match. It does not add any reserved characters to the URN syntax.

Write only digits with periods between them. Two names match only when their text is exactly the same.

§2Assignment and Resolution

OID assignment rules require each identifier to be unique and not reused. An organization assigned a node can create identifiers below it. The RFC lists the first three branches as assigned to ITU-T, ISO, and joint ISO/ITU-T assignment.

RFC 3061 defines no resolution mechanism and no validation mechanism. A correctly formatted URN therefore does not by itself prove that its OID was assigned or identify a service that can retrieve information about it.

The numbering authority controls which branches it assigns. This RFC gives no online lookup that confirms who owns a number or retrieves information about it.

EXAMPLES OF THE TOP OID BRANCHES IN RFC 3061
  • OID tree
    • 0 ITU-T assignment
    • 1 ISO assignment
      • 1.3.6.1 Internet OID
        • 1.3.6.1.4.1 IANA-assigned company OIDs
    • 2 joint ISO/ITU-T assignment

§4Security Considerations

The RFC says the namespace introduces no security considerations beyond those already inherent in using OIDs that cannot be verified. It defines a name format, not an authentication or trust mechanism.

The name format does not check whether an OID is genuine. Users must not treat the written name as proof of ownership.

§5References