Network Working Group                                            S. Kang
Request for Comments: 4179               National Computerization Agency
Category: Informational                                     October 2005


               Using 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.



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  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.  See
  http://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      : <[email protected]>
     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 in section 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 = "(" / ")" / "+" / "," / "-" / "." / "=" / "@" /
             ";" / "$" / "_" / "!" / "*" / "'"






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     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.





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  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. (Currently http://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 to RFC2141 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 at http://rootadmin.
     uci.or.kr:9000/{UCI identifier} by typing a query UCI identifier)

  Scope:

     Global.






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3.  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].










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7.  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: [email protected]






























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Acknowledgement

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  Internet Society.







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