GENWiki

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.

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.  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      : <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 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.

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. (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.

Kang Informational [Page 4] RFC 4179 URN Namespace for UCI October 2005

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].

Kang Informational [Page 5] RFC 4179 URN Namespace for UCI October 2005

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: sukang@nca.or.kr

Kang Informational [Page 6] RFC 4179 URN Namespace for UCI October 2005

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