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Versions: 00 01 02 03 04 05 06 RFC 6338

Network Working Group                                          V. Giralt
Internet-Draft                                              Univ. Malaga
Intended status: Informational                                 R. McDuff
Expires: November 19, 2011                              Univ. Queensland
                                                            May 18, 2011

Definition of a Uniform Resource Name (URN) Namespace for the Schema for
                            Academia (SCHAC)


   This document describes a Uniform Resource Name (URN) namespace for
   the Schema for Academia (SCHAC).

   The namespace described in this document is for naming persistent
   resources defined by the SCHAC participants internationally, their
   working groups, and other designated subordinates.  The main use of
   this namespace will be for the creation of controlled vocabulary
   values for attributes in the SCHAC schema.  These values will be
   associated with particular instances of persons or objects belonging
   to any of the SCHAC object classes.

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Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC 2119[1].

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Internet-Drafts are draft documents valid for a maximum of six months
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   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on November 19, 2011.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

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1.  Introduction

   The Schema for Academia (SCHAC) international activity was born
   inside the Task Force on European Middleware Coordination and
   Collaboration (TF-EMC2) of the Trans-European Research and Education
   Network Association (TERENA)[4].  The initial aim of SCHAC was to
   harmonise the disjoint person schemas of the participating countries
   in order to have a common way for expressing data about persons,
   exchanged between educational organizations.  SCHAC, as other person
   schemas, is designed to ease the sharing of information about a given
   individual between parties, mostly, but not limited to, educational
   and research institutions.  The main aims of this sharing are: to
   provide resources to individuals and to allow said individuals to
   move, virtually and physically, between such institutions.  Thus, the
   SCHAC schema was defined with input from all participants' national
   person schemas[5].

   SCHAC does not supplant other person schemas such as
   organizationalPerson [6], inetOrgPerson [7] or eduPerson [8], it
   extends those where needed for the purposes of Higher Education
   outside the United States.  This characteristic has made SCHAC,
   originally an European effort, useful for groups outside Europe.

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2.  Specification Template

   Namespace ID:


   Registration Information:

      Registration Version Number 1

      Registration Date: YYYY-MM-DD [RFC Editor, please replace with the
      date of approval of this document for publication as an RFC]

   Registrant of the namespace:

      European Committee for Academic Middleware (ECAM)
      Trans-European Research and Education Network Association (TERENA)
      The Netherlands

   Designated contacts:

      Contact: Licia Florio
      Affiliation: TERENA
      Singel 468 D
      Amsterdam, 1017 AW
      The Netherlands

      Email: florio@terena.org
      Phone: +31(0)20 5304488

      Contact: Victoriano Giralt
      Affiliation: University of Malaga
      Central ICT Services
      Blvd.  Louis Pasteur, 33
      Campus de Teatinos
      29071 Malaga

      Email: victoriano@uma.es
      Phone: +34 95 213 2366

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   Syntactic structure:

      The Namespace Specific Strings (NSS) of all URNs assigned by SCHAC
      will conform to the syntax defined in section 2.2 of RFC 2141,
      "URN Syntax"[9].  In addition, all SCHAC URN NSSs will consist of
      a left-to-right series of tokens delimited by colons.  The left-
      to-right sequence of colon-delimited tokens corresponds to
      descending nodes in a tree.  To the right of the lowest naming
      authority node, there may be zero, one, or more levels of
      hierarchical naming nodes terminating in a rightmost leaf node.
      See the section below entitled "Identifier assignment" for more on
      the semantics of NSSs.  This syntax convention is captured in the
      following normative ABNF rules for SCHAC NSSs (see RFC 5234[2]):

            SCHAC-NSS    =   1*subStChar *( ":" 1*subStChar )

            subStChar    =   trans / "%" HEXDIG HEXDIG

            trans        =   ALPHA / DIGIT / other / reserved

            other        =   "(" / ")" / "+" / "," / "-" / "." /
                             "=" / "@" / ";" / "$" /
                             "_" / "!" / "*" / "'"

            reserved     =   "/" / "?" / "#"

      The exclusion of the colon from the list of "other" characters
      means that the colon can only occur as a delimiter between string
      tokens.  Note that this ABNF rule set guarantees that any valid
      SCHAC NSS is also a valid RFC 2141 NSS.

   Relevant ancillary documentation:


   Identifier uniqueness:

      It is the responsibility of TERENA to guarantee uniqueness of the
      names of immediately subordinate naming authorities.  Each lower-
      level naming authority in turn inherits the responsibility of
      guaranteeing uniqueness of names in their branch of the naming

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   Identifier persistence:

      TERENA bears ultimate responsibility for maintaining the usability
      of SCHAC URNs over time.  This responsibility MAY be delegated to
      subordinate naming authorities per the discussion in the section
      below on identifier assignment.  That section provides a mechanism
      for the delegation to be revoked in the case a subordinate naming
      authority ceases to function.

   Identifier assignment:

      TERENA will create an initial series of immediately subordinate
      naming authorities, and will define a process for adding to that
      list of authorities.  Each country with a representative in SCHAC
      will be invited to designate a naming authority.  Country specific
      namespaces based on the country Internet TLD [10] will be assigned
      then to the designated authority.  The subordinated namespaces int
      and eu will remain under TERENA authority, controlled by the SCHAC
      activity members, for entities of global international or European
      interest.  There is also the possibility of granting subordinate
      namespaces to multi-country organizations, in this case the
      organizational Internet FQDN will be used as prefix.

      As an example, an European level interest entity would be any
      value related to information used in the Higher Education European
      Space, or the so called Bologna process.  Such entities will
      belong in the eu subordinate namespace.

      Global international entities could encompass values related to
      the Grid community or values useful both for some European and
      Australian universities.  Such entities would belong in the int
      subordinate namespace.

      Examples of multicountry organizations include TERENA itself or an
      association like EPI (educationalpolicy.org) that has members from
      Australia, Canada and the US.

      URNs intended for values of SCHAC attributes will include the
      attribute name immediately after the NSS prefix, before any
      geographical namespace delegation, such that any string can convey
      information about the attribute for which it is a value.  For
      example, values for schacUserStatus, will be of the from:

                 urn:schac:UserStatus:au or

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      Automated registry publication mechanisms will be provided if at
      all possible, based on the work on distributed URN registries done
      by the TF-EMC2 task force members.

      Institutions and communities affiliated with SCHAC participants
      may request that they be granted subordinate naming authority
      status.  Uniqueness of these namespaces under country authority
      will be based on the requestor's Internet FQDN.  This
      subordination procedure SHOULD be carried along the delegation
      chain, i.e., all entities that receive a delegated namespace MUST
      have a valid FQDN and MUST publish an Internet accessible URN
      value registry, if at all possible based on the URN registry
      mechanisms designed by the TF-EMC2 task force members.

      On at least an annual basis, TERENA will contact the liaisons or
      directors of each immediately subordinate naming authority.  If
      there is no response, or if the respondent indicates that they
      wish to relinquish naming authority, the authority over that
      branch of the tree reverts to TERENA.  This process will be
      enforced recursively by each naming authority on its subordinates.
      This process guarantees that responsibility for each branch of the
      tree will lapse for less than one year, at worst, before being
      reclaimed by a superior authority.

      Lexical equivalence of two SCHAC namespace specific strings (NSSs)
      is defined below as an exact, case-sensitive string match.  TERENA
      will assign names of immediately subordinate naming authorities in
      lowercase only.  This forestalls the registration of two SCHAC-
      subordinate naming authorities whose names differ only in case.
      Attribute names will use the same mixed case format as in the
      schema definition.

   Identifier resolution:

      The namespace is not currently listed with a Resolution Discovery
      System (RDS), but nothing about the namespace prohibits the future
      definition of appropriate resolution methods or listing with an

      TERENA will maintain a registry of all SCHAC assigned URN values,
      both final and for delegation, on its Web site:


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      Delegation entries will have a pointer to the registry of the
      subordinate naming authority.  This SHOULD recurse down the
      delegation tree, but registries for several delegated namespaces
      MAY be maintained by a single naming authority.

      All registries MUST publish their URNs using a secure web site
      offering credentials signed by a community recognised Certificate
      Authority (CA) and that WILL require the latest secure methods for
      accessing a web site, that currently being HTTP [11] over the
      latest version of TLS [12].  Registries SHOULD consider the user
      interface implications of their choice of CA, taking into account
      issues like browser alerts and blind trust.

   Lexical equivalence:

      Lexical equivalence of two SCHAC Namespace Specific Strings (NSSs)
      is defined as an exact, case-sensitive string match.

   Conformance with URN syntax:

      All SCHAC NSSs fully conform to RFC 2141 syntax rules for NSSs.

   Validation mechanism:

      As specified in the "Identifier resolution" section above, TERENA
      will maintain an index of all SCHAC assigned URNs on its Web site
      https://urnreg.terena.org/.  Presence in that registry or in any
      subordinate one implies that a given URN is valid.  Delegated
      naming authorities MUST guarantee that values are valid in their
      assigned spaces.



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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.

   In order to guarantee the validity and origin of SCHAC-NSS URN
   values, they MUST be published over links pointing to secure web
   sites offering credentials signed by a community recognised
   Certificate Authority (CA) and that WILL require the latest secure
   methods for accessing a web site, that currently being HTTP [11] over
   the latest version of TLS [12].

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4.  Namespace Considerations

   Registration of an Namespace Identifier (NID) specific to SCHAC is
   reasonable given the following considerations:

      SCHAC would like to assign URNs to some very fine-grained objects.
      This does not seem to be the primary intended use of the XMLORG
      namespace (RFC 3120) [13], or the more tightly controlled OASIS
      [14] namespace (RFC 3121) [15].

      SCHAC seeks naming autonomy.  SCHAC is not a member of OASIS, so
      becoming a subordinate naming authority under the OASIS URN space
      is not an option.  There is the MACE (Middleware Architecture
      Committee for Education) [16] namespace but the SCHAC development
      is done outside MACE activity scope and thus the attributes and
      values do not belong into the MACE namespace.  Using the MACE
      namespace requires the SCHAC namespace to be placed under one of
      the SCHAC participants namespace, which hinders its global scope.

      SCHAC will want to assign URNs to non-XML objects as well.  That
      is another reason that XMLORG may not be an appropriate higher-
      level naming authority for SCHAC.

   Some of the already defined SCHAC attribute values have been assigned
   URNs under the urn:mace:terena.org namespace.  These values will
   enter a deprecation cycle, with clear indication of them being
   replaced by values under the new namespace once it is assigned.  In
   any case, RFC 3406 [3] (which replaced RFC 2611) includes an explicit
   statement that two or more URNs may point to the same resource.

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5.  Community Considerations

   The assignment and use of identifiers within the namespace are open,
   and the related rule is established by the SCHAC activity members.
   Registration agencies (the next level naming authorities) will be the
   National Research and Education Networks (NRENs) and established
   organizational cross-border organizations that participate in SCHAC.

   It is expected that the majority of the European NRENs, their
   constituencies, participants in the Australian Access Federation and
   some other international activities make use of the SCHAC namespace.

   After the establishment of the SCHAC namespace, TERENA will establish
   a registry service (analogously to other distributed pan-European
   services, like eduroam, PerfSONAR, etc.) for the namespace clients.
   Available at:

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6.  IANA Considerations

   In accordance with BCP 66 [3], IANA is asked to register the Formal
   URN Namespace 'schac' in the Registry of URN Namespaces, using the
   registration template presented in Section 2 of this document.

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7.  Acknowledgments

   SCHAC is the result of the TERENA TF-EMC2 task force and many others
   that have contributed ideas to the development of the schema.

   This document has been discussed on the URN-NID list, with the
   special help of Alfred Hoenes who has thoroughly reviewed the
   documents and helped us correct errors and suggested clarifications
   to the text.

   Peter Saint-Andre has also provided comments that have improved the
   overall document quality, which we herein thank him.  We'd also like
   to thank Chris Lonvik for helping us express our security concerns in
   a better way.  Finally, we thank other reviewers that have helped
   giving the final touchs to the text.

   Special thanks should go to Dyonisius Visser from the TERENA tecnical
   team for taking the time and effort required to set up the root
   instance of the namespace registry.

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8.  References

8.1.  Normative References

   [1]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
         Levels", BCP 14, RFC 2119, March 1997.

   [2]   Crocker, D. and P. Overell, "Augmented BNF for Syntax
         Specifications: ABNF", STD 68, RFC 5234, January 2008.

   [3]   Daigle, L., van Gulik, D., Iannella, R., and P. Faltstrom,
         "Uniform Resource Names (URN) Namespace Definition Mechanisms",
         BCP 66, RFC 3406, October 2002.

8.2.  Informative References

   [4]   TERENA, "Trans-European Research and Education Network
         Association" http://www.terena.org/.

   [5]   TERENA TF-EMC2, "SCHAC activity web site".

   [6]   Sciberras, A., "Lightweight Directory Access Protocol (LDAP):
         Schema for User Applications", RFC 4519, June 2006.

   [7]   Smith, M., "Definition of the inetOrgPerson LDAP Object Class",
         RFC 2798, April 2000.

   [8]   MACE-Dir, "eduPerson Object Class Specification",
         December 2007.

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

   [10]  IANA, "Country TLDs". http://www.iana.org/root-whois/

   [11]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L.,
         Leach, P., and T. Berners-Lee, "Hypertext Transfer Protocol --
         HTTP/1.1", RFC 2616, June 1999.

   [12]  Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS)
         Protocol Version 1.2", RFC 5246, August 2008.

   [13]  Best, K. and N. Walsh, "A URN Namespace for XML.org", RFC 3120,
         June 2001.

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   [14]  OASIS, "Organization for the Advancement of Structured
         Information Standards: OASIS". http://www.oasis-open.org/

   [15]  Best, K. and N. Walsh, "A URN Namespace for OASIS", RFC 3121,
         June 2001.

   [16]  Internet2, "Middleware Architecture Committee for Education:
         MACE". http://www.internet2.edu/MACE

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Authors' Addresses

   Victoriano Giralt M.D.
   University of Malaga
   Avd. Cervantes, 2
   Malaga, Malaga  E-29071

   Phone: +34-95-213-2366
   Email: victoriano@uma.es
   URI:   http://www.uma.es/

   Dr. Rodney McDuff
   The University of Queensland

   Email: r.mcduff@uq.edu.au
   URI:   http://www.uq.edu.au/

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