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Network Working Group                                            S. KangRequest for Comments: 4179               National Computerization AgencyCategory: Informational                                     October 2005Using Universal Content Identifier (UCI)as Uniform Resource Names (URN)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 (2005).Abstract   This document describes a Uniform Resource Name (URN) namespace for   the National Computerization Agency (NCA) for naming persistent   digital resources such as music, videos, texts, images, e-books, and   other types of digital resources produced or managed by NCA.1.  Introduction   NCA is a non-profit organization with a mandate to develop and   promote information infrastructure and manage public digital contents   in Korea and possibly worldwide.   NCA has been supervising digitalization projects with various   organizations.  The contents involved in such projects include   millions of technical papers, cultural properties, educational   materials, scientific research reports.  Those organizations manage   the digital contents in a standardized way set by NCA and provide   users with various content services via internet.   NCA wishes to issue globally unique and persistent IDs to digital   resources and assign relevant organizations as its registration   agencies under the Universal Content Identifier (UCI) scheme.  It is   beneficial for NCA, its registration agencies, and the value chain   players in e-commerce, to have the UCI URN namespace, under which all   the contents and components produced and managed by NCA are digitally   registered, identified, and resolved.   NCA has been developing and operating the UCI system that provides   registration, resolution, search, and administration functionalities.Kang                         Informational                      [Page 1]

RFC 4179                 URN Namespace for UCI              October 2005   The functionalities are going to be added and modified once the use   of UCI URN namespace is approved.  NCA would like to assign unique,   permanent, and location-independent names based on the URNs for the   resources it produces or manages.  Seehttp://www.nca.or.kr/eindex.htm for more information on NCA.   This namespace specification is for a formal namespace.2.  Specification Template   Namespace ID:      "UCI"   Registration Information:      Registration Version Number: 1       Registration Date: 2004-07-xx   Declared registrant of the namespace:      Name       : Sang-ug Kang      Affiliation: National Computerization Agency      Address    : NCA Bldg. 77 Mookyo-Dong, Chung-Ku, Seoul, Korea      Phone      : +82 (2) 2131-0443      Email      : <sukang@nca.or.kr>      Web        : <http://www.nca.or.kr> or <http://home.uci.or.kr>   Declaration of syntactic structure:      The Namespace specific string of all URNs assigned by NCA conforms      to the syntax defined insection 2.2. of RFC2141, "URN Syntax"[1].      The syntax convention is described in the form of ABNF rules [2]      as the following.      UCI = prefix "-" instance *1(":" qualifier)      prefix = 1*(alphaDigit) *1(":" 1*(alphaDigit))               *1("+" 1*(alphaDigit))      instance = 1*(trans / "%" HEXDIG HEXDIG)      qualifier = head 1*(alphaDigit) *2("-" head 1*(alphaDigit))      trans = alphaDigit / other      alphaDigit = ALPHA / DIGIT      head = "C" / "R" / "F"      other = "(" / ")" / "+" / "," / "-" / "." / "=" / "@" /              ";" / "$" / "_" / "!" / "*" / "'"Kang                         Informational                      [Page 2]

RFC 4179                 URN Namespace for UCI              October 2005      The UCI identifier consists of two parts: prefix code and content      code.  The content code is also divided into instance code and      qualifier code, which is optional.  A prefix code is given to a      registration agency, subordinate registration agency, and/or its      registrants such as 'G3000+music', 'I600', 'I500+paper', and so      forth.  A content code is issued to each individual digital      resource such as 'cii90007', '8987409', and so on.   Relevant ancillary documentation:      None.   Identifier uniqueness considerations:      It is the responsibility of the registration authority, or NCA, to      guarantee the uniqueness of identifiers and the names of      subordinate naming authorities.  For example, a software tool      developed and used by NCA checks if a UCI identifier is being      reassigned and verifies that it is assigned to at most one      resource during the registration process.   Identifier persistence considerations:      Registration Agencies are all eligible to maintain the usability      of the UCI URNs for a reasonably long period.  As a government      sponsored organization, NCA will operate a backup service and make      an effort to find a substitute in case a registration agency      becomes out of operation.   Process of identifier assignment:      Assignment of UCI identifier is delegated to the registration      agencies.  NCA appoints UCI registration agencies and provides its      namespace by assigning a unique registration agency code that is a      part of NSS.  Followed by the authorized namespace, each      registration agency sets its own identifier scheme that conforms      to the UCI syntactic structure.      A UCI for a digital resource is issued by the registration agency,      upon a request of a registrant.  The following is an example      identifier.      e.g., urn:uci:I700-2987098      where, I700 is a registration agency code and 2987098 is an      identifier assigned to a digital content.Kang                         Informational                      [Page 3]

RFC 4179                 URN Namespace for UCI              October 2005   Process for identifier resolution:      Resolution is controlled by NCA and its delegatees.  The list of      UCI registration agency codes is maintained by the registration      authority.  Each registration agency maintains the list of      subordinate registrant codes and identifiers registered to the      registration agency.      Identifier resolution steps are as follows.      - (Step1) Global resolution: NCA resolves which RA is dealing with        the associated resource by parsing the registration agency code        of the UCI.      - (Step2) Local resolution: The corresponding RA parses and        resolves the rest of the identifier      The global resolution is performed by UCI resolution server that      is open to public. (Currentlyhttp://rootadmin.uci.or.kr:9000/      {UCI identifier} will give you resolution results.)   Rules for Lexical Equivalence:      The "prefix" is case-insensitive.  So there will not be two      registration agencies whose names differ only in case.         urn:uci:{prefix code}:      is case-insensitive for matches.  Remainder of the identifier is      case-sensitive.   Conformance with URN Syntax:      The UCI syntax fully conforms toRFC2141 syntax rules for both NSS      and NID.   Validation mechanism:      Valid list of prefix code will be available via both on-line and      off-line upon request.  The validity of the rest of identifier can      be offered via on-line service. (Currently athttp://rootadmin.uci.or.kr:9000/{UCI identifier} by typing a query UCI identifier)   Scope:      Global.Kang                         Informational                      [Page 4]

RFC 4179                 URN Namespace for UCI              October 20053.  Security Considerations   There are no additional security considerations beyond those normally   associated with the use and resolution of URNs in general.4.  Namespace Considerations   The Korean government has been funding the UCI project with the   vision that it will be an essential component in realizing   interoperability of digital contents owned by individual institutes   and organizations.  The resolution service provided by NCA and its   registration agencies via networks will play a central role in   achieving such a goal.  Moreover, the resolution service is open to   the public without discrimination.   The assignment and use of identifiers is performed according to the   rules established by NCA.  It abides by the URN requirements and   syntax.  Within a UCI namespace, a registration agency manages   subordinate namespaces and maintains the metadata of digital   contents.   For making the service available to the public, a global resolution   service is run by NCA through a service server and local resolution   service is provided by the corresponding registration agency.5.  Community Considerations   The assignment and use of identifiers within the namespace are open,   and the related rule is established by NCA.  Registration agencies   are evaluated and selected fairly and shall have the responsibility   of processing registrants' requests for registering digital contents.   Registration authority and registration agencies shall operate   resolution servers for UCI namespace and subordinate namespaces,   respectively.  Digital content users can access the resolution   servers to fetch resolution results.  The reference software is   developed, and resolution servers are now in operation.6.  IANA Considerations   The IANA has registered the "UCI" namespace in the IANA registry of   URN NIDs.  For more information about URN namespace, see [3].Kang                         Informational                      [Page 5]

RFC 4179                 URN Namespace for UCI              October 20057.  Normative References   [1]  Moats, R., "URN Syntax",RFC 2141, May 1997.   [2]  Crocker, D. and P. Overell, "Augmented BNF for Syntax        Specifications: ABNF",RFC 2234, November 1997.   [3]  Daigle, L., van Gulik, D., Iannella, R., and P. Faltstrom,        "Uniform Resource Names (URN) Namespace Definition Mechanisms",BCP 66,RFC 3406, October 2002.Author's Address   Sang-ug Kang   National Computerization Agency   Bldg. 77 Mookyo-Dong,   Joong-Ku, Seoul,   Korea   Phone: 82-2-2131-0443   EMail: sukang@nca.or.krKang                         Informational                      [Page 6]

RFC 4179                 URN Namespace for UCI              October 2005Full Copyright Statement   Copyright (C) The Internet Society (2005).   This document is subject to the rights, licenses and restrictions   contained inBCP 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 inBCP 78 andBCP 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 athttp://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.Kang                         Informational                      [Page 7]