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Network Working Group                                        M. MeallingRequest for Comments: 3553                                      VeriSignBCP: 73                                                      L. MasinterCategory: Best Current Practice                            Adobe Systems                                                               T. Hardie                                                                Qualcomm                                                                G. Klyne                                                            Nine by Nine                                                               June 2003An IETF URN Sub-namespace for Registered Protocol ParametersStatus of this Memo   This document specifies an Internet Best Current Practices for the   Internet Community, and requests discussion and suggestions for   improvements.  Distribution of this memo is unlimited.Copyright Notice   Copyright (C) The Internet Society (2003).  All Rights Reserved.Abstract   This document describes a new sub-delegation for the 'ietf' URN   namespace for registered protocol items.  The 'ietf' URN namespace is   defined inRFC 2648 as a root for persistent URIs that refer to   IETF-defined resources.1.  Introduction   From time to time IETF standards require the registration of various   protocol elements in well known central repository.  The Internet   Assigned Numbers Authority maintains this central repository and   takes direction from the IETF on what, how and when to add items to   it.  The IANA maintains lists of items such as all assigned port   numbers, MIME media types, enterprise numbers, etc.   Over time there has developed a need to be able to reference these   elements as URIs in various schema.  In the past this was done in a   very ad hoc way that easily led to interoperability problems.  This   document creates a new sub-delegation below the "ietf" [2]URN   namespace [1] called 'params' which acts as a standardized mechanism   for naming the items registered for IETF standards.  Any assignments   below that are specified in an RFC according to the IETF consensus   process and which include the template found inSection 4.Mealling, et. al.        Best Current Practice                  [Page 1]

RFC 3553                   IANA URN Namespace                  June 20032.  Terminology   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 inRFC 2119.3.  IETF Sub-namespace Specifics   Sub-namespace name:      params   Declared registrant of the namespace:      The Internet Engineering Task Force   Declaration of structure:      The namespace is primarily opaque.  The IANA, as operator of the      registry, may take suggestions for names to assign but they      reserve the right to assign whatever name they desire, within      guidelines set by the IESG.  The colon character (":") is used to      denote a very limited concept of hierarchy.  If a colon is present      then the items on both sides of it are valid names.  In general,      if a name has a colon then the item on the left hand side      represents a class of those items that would contain other items      of that class.  For example, a name can be assigned to the entire      list of DNS resource record type codes as well as for each      individual code.  The URN for the list might look like this:            urn:ietf:params:dns:rr-type-codes      while the URN for the SOA records type code might look like this:            urn:ietf:params:dns:rr-type-codes:soa   Relevant ancillary documentation:      [3], [2], [1]   Identifier uniqueness considerations:      The IESG uses the IETF consensus process to ensure that      sub-namespaces generate unique names within that      sub-namespace.  The IESG delegates to the IANA the task of      ensuring that the sub-namespace names themselves are unique.      Until and unless the IESG specifies differently, the IANA is      directed to ensure uniqueness by comparing the name to be assignedMealling, et. al.        Best Current Practice                  [Page 2]

RFC 3553                   IANA URN Namespace                  June 2003      with the list of previously assigned names.  In the case of a      conflict the IANA is to request a new string from the registrant      until the conflict is resolved.   Identifier persistence considerations:      Once a name has been allocated it MUST NOT be re-allocated for a      different purpose.  The rules provided for assignments of values      within a sub-namespace MUST be constructed so that the meaning of      values cannot change.  This registration mechanism is not      appropriate for naming values whose meaning may change over time.      If a value that changes over time the assignment MUST name the      container or concept that contains the value, not the value      itself.  For example, if a parameter called 'foo' has a value that      changes over time, it is valid to create the name      'urn:ietf:params:foo-params:foo' that identifies that 'slot'.  It      is not valid to actually create a name that contains that value      unless it is a persistent and unique value such as a version      number.   Process of identifier assignment:      Identifiers are assigned only after a particular protocol element      or number has been registered with the IANA using standard      policies and procedures, or documented in an RFC describing a      standards track protocol.  This means that the 'gating' function      for assignment is the "IETF Consensus" process documented inRFC2434 [4].   Process of identifier resolution:      At this time no resolution mechanism is defined.   Rules for Lexical Equivalence:      Lexical equivalence is achieved by exact string match according to      the rules for URN syntax found inRFC 2141 [1].  Specifically, due      to the URN syntax definitions, the 'stringprep' standard found inRFC 3454 [7] does not apply.   Conformance with URN Syntax:      There are no additional characters reserved.   Validation mechanism:      None.Mealling, et. al.        Best Current Practice                  [Page 3]

RFC 3553                   IANA URN Namespace                  June 2003   Scope:      Global4.  Assigning Names   The creation of a new registry name will be simple for most flat   registries.  The only required elements will be the registry name, a   reference to relevant documents, a statement about which   current/proposed document repositories contains the authoritative   data for the registry, and a statement specifying which element in   the registry is the value to be used in the URN.  In most cases this   last element will be the index value assigned by the IANA.   More complex registries (DNS Parameters for example) will need to   repeat that information for any sub-namespaces.  It should also be   clear as to whether or not a name is assigned to the sub-namespace   itself (i.e., is 'urn:ietf:params:dns:rr-types' valid by itself and   if so, what does it name?).   The template:   Registry name: -- The name of the sub-namespace.  In many cases this      should be the same name that the IANA calls the registry itself.   Specification: -- Relevant IETF published documents that define the      registry and the items in it.   Repository: -- A pointer to the 'current' location of the registry in      the protocol parameters repository or the relevant RFCs that      document the items being named.  This value will change over time      as the entity that maintains the repository moves files and or      fileservers.  It is not meant as a permanent binding to the      filename but as a hint to the IANA for what the initial mapping      would be.   Index value: -- Description of how a registered value is to be      embedded in the URI form.  This MUST include details of any      transformations that may be needed for the resulting string to      conform to URN syntax rules and any canonicalization needed so      that the case-sensitive string comparison yields the expected      equivalences.   The process for requesting that a URN be assigned is currently to put   the above template or a reference to it in the IANA considerations   section of the specifying document.  Other more automated processes   may be proposed at a latter time if demand requires it.Mealling, et. al.        Best Current Practice                  [Page 4]

RFC 3553                   IANA URN Namespace                  June 20035.  Security Considerations   None not already inherent to using URNs.  Security considerations for   URNs in general can be found inRFC 2141 [1].  Further security   considerations for one specific URN resolution method can be found in   Dynamic Delegation  Discovery System (DDDS) Part Four: The Uniform   Resource Identifiers (URI) Resolution Application (RFC 3404) [5]   which is part of a series starting with Dynamic  Delegation Discovery   System (DDDS) Part One: The Comprehensive DDDS  (RFC 3401) [6].6.  IANA Considerations   This document puts a new and significant burden on the IANA since it   may require an additional assignment process to happen for each new   IANA registry.  To minimize the administrative burden on IANA, any   parameter namespace registration is very clear about the criteria for   inclusion in that namespace.   Defining a registry that fits the constraints of a URN namespace will   impose extra discipline that should take some of the guess-work about   creating and maintaining that registry.7.  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 inBCP-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.Mealling, et. al.        Best Current Practice                  [Page 5]

RFC 3553                   IANA URN Namespace                  June 20038.  Normative References   [1]  Moats, R., "URN Syntax",RFC 2141, May 1997.   [2]  Moats, R., "A URN Namespace for IETF Documents",RFC 2648,        August 1999.   [3]  Daigle, L., van Gulik, D., Iannella, R. and P. Faltstrom,        "Uniform Resource Names (URN) Namespace Definition Mechanisms",BCP 66,RFC 3406, October 2002.   [4]  Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA        Considerations Section in RFCs",BCP 26,RFC 2434, October 1998.   [5]  Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part        Four: The Uniform Resource Identifiers (URI)",RFC 3404,        February 2002.   [6]  Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part        One: The Comprehensive DDDS",RFC 3401, May 2002.   [7]  Hoffman, P. and M. Blanchet, "Preparation of Internationalized        Strings ("stringprep")",RFC 3454, December 2002.Mealling, et. al.        Best Current Practice                  [Page 6]

RFC 3553                   IANA URN Namespace                  June 20039.  Authors' Addresses   Michael Mealling   VeriSign   21345 Ridgetop Circle   Sterling, VA  20166   US   EMail: michael@verisignlabs.com, michael@neonym.net   URI:http://www.verisign.com   Larry Masinter   Adobe Systems Incorporated   345 Park Ave   San Jose, CA  95110   US   Phone: +1 408 536-3024   EMail: LMM@acm.org   URI:http://larry.masinter.net   Ted Hardie   Qualcomm, Inc.   675 Campbell Technology Parkway   Suite 200   Campbell, CA   U.S.A.   EMail: hardie@qualcomm.com   Graham Klyne   Nine by Nine   EMail: GK-IETF@ninebynine.org   URI:http://www.ninebynine.net/Mealling, et. al.        Best Current Practice                  [Page 7]

RFC 3553                   IANA URN Namespace                  June 200310.  Full Copyright Statement   Copyright (C) The Internet Society (2003).  All Rights Reserved.   This document and translations of it may be copied and furnished to   others, and derivative works that comment on or otherwise explain it   or assist in its implementation may be prepared, copied, published   and distributed, in whole or in part, without restriction of any   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   Internet organizations, except as needed for the purpose of   developing Internet standards in which case the procedures for   copyrights defined in the Internet Standards process must be   followed, or as required to translate it into languages other than   English.   The limited permissions granted above are perpetual and will not be   revoked by the Internet Society or its successors or assigns.   This document and the information contained herein is provided on an   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.Acknowledgement   Funding for the RFC Editor function is currently provided by the   Internet Society.Mealling, et. al.        Best Current Practice                  [Page 8]