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Network Working Group                                          R. MorganRequest for Comments: 3613                           Univ. of WashingtonCategory: Informational                                      K. Hazelton                                              Univ. of Wisconsin-Madison                                                            October 2003Definition of a Uniform Resource Name (URN) Namespace for theMiddleware Architecture Committee for Education (MACE)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 (2003).  All Rights Reserved.Abstract   This document describes a Uniform Resource Name (URN) namespace for   the Internet2 Middleware Architecture Committee for Education (MACE).   This namespace is for naming persistent resources defined by MACE,   its working groups and other designated subordinates.1.  Introduction and Community Considerations   The Internet2 Middleware Architecture Committee for Education (MACE)   produces many kinds of documents: specifications, working drafts,   object classes, schemas, stylesheets, etc.  It also defines directory   attributes and controlled vocabularies for the values of some of   those attributes.   MACE wishes to provide global, distributed, persistent, location-   independent names for these resources.  The Uniform Resource Name   (URN) variant of URIs meets these requirements.   MACE working groups and other MACE-affiliated groups will benefit   from the MACE URN namespace by having an easy, efficient way to   assign globally unique, persistent identifiers to resources that they   create.  The nature of MACE work is that serves the needs of one or   more communities of interest.  A namespace managed so as to   facilitate the creation, registration and resolution of unique,   persistent identifiers will be of great value for MACE, its   affiliates and the higher education community generally.Morgan & Hazelton            Informational                      [Page 1]

RFC 3613                 URN Namespace for MACE             October 2003   This URN namespace specification is for a formal namespace.2.  Specification Template   Namespace ID:      "mace"   Registration Information:      Registration Version Number 1      Registration Date: 2003-08-01   Registrant of the namespace:      Middleware Architecture Committee for Education (MACE)      ATTN: Lisa Hogeboom      Internet2      3025 Boardwalk  Suite 200      Ann Arbor, MI 48108      Phone: +1 734 913 4250      Contact: Keith Hazelton      Affiliation: Univ.  of Wisconsin-Madison      1210 W.  Dayton St.      Madison, WI  53706      Phone: +1 608 262 0771      hazelton@doit.wisc.edu   Syntactic structure:      The Namespace Specific Strings (NSS) of all URNs assigned by MACE      will conform to the syntax defined insection 2.2 of RFC 2141,      "URN Syntax" [1].  In addition, all MACE 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 entitled "Identifier assignment" below for more on      the semantics of NSSs.  This syntax convention is captured in the      following normative ABNF rules for MACE NSSs (seeRFC 2234) [2]:Morgan & Hazelton            Informational                      [Page 2]

RFC 3613                 URN Namespace for MACE             October 2003      MACE-NSS        =   1*(subStChar) 0*(":" 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      MACE NSS is also a validRFC 2141 NSS.   Relevant ancillary documentation:      None.   Identifier uniqueness:      It is the responsibility of MACE directors 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      tree.   Identifier persistence:      MACE directors bear ultimate responsibility for maintaining the      usability of MACE 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 case a subordinate      naming authority ceases to function.   Identifier assignment:      MACE directors will create an initial series of immediately      subordinate naming authorities, and will define a process for      adding to that list of authorities.  Each top-level working group      of MACE will be invited to designate a naming authority and to      suggest one or more candidate names for that authority.  The      MACE-Shibboleth group, for example, might propose creating aMorgan & Hazelton            Informational                      [Page 3]

RFC 3613                 URN Namespace for MACE             October 2003      naming authority under "urn:mace:shib," "urn:mace:shibboleth" or      some other name.      Institutions and communities affiliated with MACE may request,      through their designated MACE liaison, that they be granted MACE-      subordinate naming authority status.  They may propose candidate      names for that authority.  One way for such entities to guarantee      uniqueness of their proposed name is to base it on a DNS name.      That is, if Georgetown University wished to be designated a      subordinate naming authority under MACE, the institutional MACE      liaison could propose to MACE directors that they be delegated      control over names beginning with "urn:mace:georgetown.edu".      Institutions seeking affiliation with MACE should send email to      mace-submit@internet2.edu, nominating an institutional liaison and      providing contact information for that person.      On at least an annual basis, MACE directors 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 MACE.  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 MACE namespace specific strings (NSSs)      is defined below as an exact, case-sensitive string match.  MACE      will assign names of immediately subordinate naming authorities in      a case-insensitive fashion, so that there will not be two MACE-      subordinate naming authorities whose names differ only in case.   Identifier resolution:      MACE directors will maintain an index of all MACE and MACE      workgroup assigned URNs at the web sitehttp://middleware.internet2.edu/urn-mace/urn-mace.html.  That      index will map URNs to resource identifiers or resource      specifications (e.g., protocol parameters).  MACE-affiliated      naming authorities will specify how to resolve the URNs they      assign if they are resolvable.   Lexical equivalence:      Lexical equivalence of two MACE namespace specific strings (NSSs)      is defined as an exact, case-sensitive string match.   Conformance with URN syntax:Morgan & Hazelton            Informational                      [Page 4]

RFC 3613                 URN Namespace for MACE             October 2003      All MACE NSSs fully conform toRFC 2141 syntax rules for NSSs.   Validation mechanism:      As specified in the "Identifier resolution" section above, MACE      directors will maintain an index of all MACE and MACE workgroup      assigned URNs on its web site,http://middleware.internet2.edu/urn-mace/urn-mace.html.  Presence      in that index implies that a given URN is valid.  MACE-affiliated      naming authorities will specify how to validate the URNs they      assign.   Scope:      Global.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   Registration of an NID specific to MACE is reasonable given the   following considerations:   1. MACE would like to assign URNs to some very fine-grained objects      (such as specific controlled vocabulary values of an attribute in      MACE-defined LDAP object classes).  This does not seem to be the      primary intended use of the XMLORG namespace (RFC 3120) [3], let      alone the more tightly controlled OASIS namespace (RFC 3121) [4].   2. MACE seeks naming autonomy.  We understand that the XMLORG      registrants left the door open to subordinate naming authorities,      "OASIS may assign portions of its XMLORG namespace for assignment      by other parties" (RFC 3120) [3], but there is no specified      process for such assignment.  That would in any case mean having a      fixed XMLORG-assigned prefix on every single object to which we      assign a URN.  MACE has a number of active work groups that may      well generate a growing number of subordinate naming authorities.      Moreover, MACE is not a member of OASIS, so becoming a subordinate      naming authority under the OASIS URN space is currently not an      option.Morgan & Hazelton            Informational                      [Page 5]

RFC 3613                 URN Namespace for MACE             October 2003   3. MACE 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 MACE.   Some MACE-developed schema and namespaces may be good candidates for   inclusion in the XMLORG registry.  The fact that such an object might   already have a MACE-assigned URN shouldn't be a hindrance.  Work is   in progress to updateRFC 2611 [5], which includes an explicit   statement that two or more URNs may point to the same resource.  A   resource with a MACE-assigned namespace-specific-string would, of   course, be given an XMLORG namespace-specific-string at the time it   enters the XMLORG registry.5.  IANA Considerations   The IANA has formally registered URN namespace 13 to MACE, within the   IANA registry of URN NIDs.6.  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]  Best, K. and N. Walsh, "A URN Namespace for XML.org",RFC 3120,        June 2001.   [4]  Best, K. and N. Walsh, "A URN Namespace for OASIS",RFC 3121,        June 2001.   [5]  Daigle, L., van Gulik, D., Iannella, R. and P. Faltstrom, "URN        Namespace Definition Mechanisms",BCP 33,RFC 2611, June 1999.Morgan & Hazelton            Informational                      [Page 6]

RFC 3613                 URN Namespace for MACE             October 20037.  Authors' Addresses   RL "Bob" Morgan   4545 15th Ave. NE   Seattle, WA  98105   U.S.A.   EMail: rlmorgan@washington.edu   Keith D. Hazelton   University of Wisconsin-Madison   1210 W. Dayton St.   Madison, WI  53706   U.S.A.   EMail: hazelton@doit.wisc.eduMorgan & Hazelton            Informational                      [Page 7]

RFC 3613                 URN Namespace for MACE             October 20038.  Full Copyright Statement   Copyright (C) The Internet Society (2003).  All Rights Reserved.   This document and translations of it may be copied and furnished to   others, and derivative works that comment on or otherwise explain it   or assist in its implementation may be prepared, copied, published   and distributed, in whole or in part, without restriction of any   kind, provided that the above copyright notice and this paragraph are   included on all such copies and derivative works.  However, this   document itself may not be modified in any way, such as by removing   the copyright notice or references to the Internet Society or other   Internet organizations, except as needed for the purpose of   developing Internet standards in which case the procedures for   copyrights defined in the Internet Standards process must be   followed, or as required to translate it into languages other than   English.   The limited permissions granted above are perpetual and will not be   revoked by the Internet Society or its successors or assignees.   This document and the information contained herein is provided on an   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING   TASK FORCE DISCLAIMS 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.Acknowledgement   Funding for the RFC Editor function is currently provided by the   Internet Society.Morgan & Hazelton            Informational                      [Page 8]