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Internet Engineering Task Force (IETF)                         V. Giralt
Request for Comments: 6338                                  Univ. Malaga
Category: Informational                                        R. McDuff
ISSN: 2070-1721                                         Univ. Queensland
                                                             August 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.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at

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RFC 6338                   SCHAC URN Namespace               August 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
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

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
   Networking Association (TERENA) [6].  The initial aim of SCHAC was to
   harmonize 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 are 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 [7].

   SCHAC does not supplant other person schemas such as
   organizationalPerson [8], inetOrgPerson [9], or eduPerson [10]; it
   extends those where needed for the purposes of Higher Education
   outside the United States.  This characteristic has made SCHAC,
   originally a European effort, useful for groups outside Europe.

2.  Requirements Language

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

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3.  Specification Template

   Namespace ID:


   Registration Information:

      Registration Version Number 1

      Registration Date: 2011-06-22

   Registrant of the namespace:

      European Committee for Academic Middleware (ECAM)
      Trans-European Research and Education Networking Association
      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 1415

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RFC 6338                   SCHAC URN Namespace               August 2011

   Syntactic structure:

      The Namespace Specific Strings (NSSs) of all URNs assigned by
      SCHAC will conform to the syntax defined in Section 2.2 of
      RFC 2141, "URN Syntax" [11].  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 "Identifier assignment" section below 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 its branch of the naming tree.

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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 where 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.  Such a list, and the policy for adding to
      it, will be published at the root registry page.  Each country
      with a representative in SCHAC will be invited to designate a
      naming authority.  Country-specific namespaces based on the
      country Internet Top-Level Domain (TLD) [12] will then be assigned
      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 Fully Qualified Domain Name
      (FQDN) will be used as the prefix.

      As an example, a 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 for
      some Australian universities.  Such entities would belong in the
      int subordinate namespace.

      Examples of multi-country organizations include TERENA itself or
      an association like the Educational Policy Institute (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 form:

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                urn:schac:userStatus:au or

      If at all possible, automated registry publication mechanisms will
      be provided, 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., if at all possible, all entities that receive a
      delegated namespace MUST have a valid FQDN and MUST publish an
      Internet accessible URN value registry, 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 RDS.

      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 over https links [3].  The
      https links MUST be secured by sites offering credentials signed
      by a SCHAC-community recognized Certification Authority (CA) using
      the latest secure methods for accessing a web site (which at
      present is the latest version of Transport Layer Security (TLS)
      [4]).  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 registry implies that a given URN is valid.  Delegated
      naming authorities MUST guarantee that values are valid in their
      assigned spaces.



4.  Examples

   The following examples are not guaranteed to be real.  They are
   listed for pedagogical reasons only.


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5.  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 https links [3].  The https links
   MUST be secured by sites offering credentials signed by a SCHAC-
   community recognized Certification Authority (CA) using the latest
   secure methods for accessing a web site (which at present is the
   latest version of TLS [4]).

6.  Namespace Considerations

   Registration of a 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 XML.org
      namespace (RFC 3120) [13], or the more tightly controlled
      Organization for the Advancement of Structured Information
      Standards (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) (RFC 3613) [16] namespace, but the SCHAC
      development is done outside of the MACE activity scope; thus, the
      attributes and values do not belong in the MACE namespace.  Using
      the MACE namespace requires that the SCHAC namespace be placed
      under one of the SCHAC participants' namespaces, which hinders its
      global scope.

      SCHAC will want to assign URNs to non-XML objects as well.  That
      is another reason that XML.org 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 a clear indication that they will be
   replaced by values under the new namespace once it is assigned.  In
   any case, RFC 3406 [5] (which replaced RFC 2611) includes an explicit
   statement that two or more URNs may point to the same resource.

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7.  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 will make use of the SCHAC

   After the establishment of the SCHAC namespace, TERENA will establish
   a registry service (analogously to other distributed pan-European
   services, such as eduroam, PerfSONAR, etc.) for the namespace
   clients.  This registry will be available via the root page of the
   namespace: https://urnreg.terena.org/.  The policy for registrations
   will be defined in documents available at the root page of the

8.  IANA Considerations

   In accordance with BCP 66 [5], IANA has registered the Formal URN
   Namespace 'schac' in the Registry of URN Namespaces, using the
   registration template presented in Section 2 of this document.

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

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

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

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10.  References

10.1.  Normative References

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

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

   [3]   Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.

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

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

10.2.  Informative References

   [6]   TERENA, "Trans-European Research and Education Networking
         Association", <http://www.terena.org/>.

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

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

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

   [10]  MACE-Dir, "eduPerson Object Class Specification",
         December 2007, <http://middleware.internet2.edu/eduperson/docs/

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

   [12]  IANA, "Country TLDs", <http://www.iana.org/domains/root/db/>.

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

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

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RFC 6338                   SCHAC URN Namespace               August 2011

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

   [16]  Morgan, R. and K. Hazelton, "Definition of a Uniform Resource
         Name (URN) Namespace for the Middleware Architecture Committee
         for Education (MACE)", RFC 3613, October 2003.

Authors' Addresses

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

   Phone: +34-95-213-1415
   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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