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Internet Engineering Task Force (IETF)                       M. BlanchetRequest for Comments: 7738                               A. SchiltknechtCategory: Informational                                    Viagenie/SANAISSN: 2070-1721                                                P. Shames                                         Jet Propulsion Laboratory, NASA                                                            January 2016A Uniform Resource Name (URN) Namespace forthe Consultative Committee for Space Data Systems (CCSDS)Abstract   This document describes a Uniform Resource Name (URN) namespace   intended for persistently and uniquely naming resources published by   the Consultative Committee for Space Data Systems (CCSDS).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; seeSection 2 of RFC 5741.   Information about the current status of this document, any errata,   and how to provide feedback on it may be obtained athttp://www.rfc-editor.org/info/rfc7738.Copyright Notice   Copyright (c) 2016 IETF Trust and the persons identified as the   document authors.  All rights reserved.   This document is subject toBCP 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.Blanchet, et al.              Informational                     [Page 1]

RFC 7738                 URN Namespace for CCSDS            January 2016Table of Contents1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .22.  Requirements Language Section . . . . . . . . . . . . . . . .33.  URN Specification for "ccsds" Namespace ID  . . . . . . . . .33.1.  Namespace ID  . . . . . . . . . . . . . . . . . . . . . .33.2.  Registration Information  . . . . . . . . . . . . . . . .33.3.  Declared Registrant of the Namespace  . . . . . . . . . .33.4.  Declaration of Syntactic Structure  . . . . . . . . . . .43.5.  Relevant Ancillary Documentation  . . . . . . . . . . . .43.6.  Identifier Uniqueness Considerations  . . . . . . . . . .43.7.  Identifier Persistence Considerations . . . . . . . . . .43.8.  Process of Identifier Assignment  . . . . . . . . . . . .53.9.  Process for Identifier Resolution . . . . . . . . . . . .53.10. Rules for Lexical Equivalence . . . . . . . . . . . . . .53.11. Conformance with URN Syntax . . . . . . . . . . . . . . .53.12. Validation Mechanism  . . . . . . . . . . . . . . . . . .53.13. Scope . . . . . . . . . . . . . . . . . . . . . . . . . .54.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . .65.  Namespace Considerations  . . . . . . . . . . . . . . . . . .66.  Community Considerations  . . . . . . . . . . . . . . . . . .67.  Security Considerations . . . . . . . . . . . . . . . . . . .68.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .69.  References  . . . . . . . . . . . . . . . . . . . . . . . . .79.1.  Normative References  . . . . . . . . . . . . . . . . . .79.2.  Informative References  . . . . . . . . . . . . . . . . .7   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .8   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .81.  Introduction   The Consultative Committee for Space Data Systems (CCSDS) [CCSDS] was   formed in 1982 by the major space agencies of the world to provide a   forum for discussion of common problems in the development and   operation of space data systems.  At the time of publication of this   document, it is composed of eleven member agencies, twenty-eight   observer agencies, and over 100 industrial associates.  Since its   establishment, CCSDS has been actively developing recommendations for   data- and information-systems standards, intended to promote   interoperability and cross support among cooperating space agencies.   CCSDS has a permanent secretariat reporting to the CCSDS Engineering   Steering Group, which maintains documents for the CCSDS protocols.   CCSDS also has its Naming Authority under the Space Assigned Number   Authority (SANA) [SANA] that manages its registries and namespaces.Blanchet, et al.              Informational                     [Page 2]

RFC 7738                 URN Namespace for CCSDS            January 2016   CCSDS produces protocol standards documents requiring a permanent and   unique namespace.  CCSDS also uses Extensible Markup Language (XML)   schemas to define XML messaging in its various protocols   recommendations.  These schemas require a persistent, unique, and   location-independent namespace for identification purposes.   This namespace specification is for a formal namespace identifier   (NID), as per [RFC3406].2.  Requirements Language Section   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this   document are to be interpreted as described in [RFC2119].3.  URN Specification for "ccsds" Namespace ID3.1.  Namespace ID      "ccsds"3.2.  Registration Information      Registration version number: 1      Registration date: 2015-10-193.3.  Declared Registrant of the Namespace   Registering organization:      Consultative Committee for Space Data Systems (CCSDS) Secretariat      Office of Space Communication (Code M-3)      National Aeronautics and Space Administration      Washington, DC 20546, USA      Email: secretariat@mailman.ccsds.org   Designated Contact:      Space Assigned Numbers Authority (SANA)      Email: info@sanaregistry.orghttp://sanaregistry.orgBlanchet, et al.              Informational                     [Page 3]

RFC 7738                 URN Namespace for CCSDS            January 20163.4.  Declaration of Syntactic Structure   The formal syntax definitions below are given in ABNF [RFC5234].   The namespace-specific string (NSS) in the urn:ccsds names hierarchy   begins with a subnamespace identifier (SNID), followed by a delimiter   and a subnamespace-dependent string   CCCSDS-URN = "urn:ccsds:" SNID ":" SUBNAMESPACE-SPECIFIC-STRING   where <SNID> is a unique subnamespace identifier for the   specification, and <SUBNAMESPACE-SPECIFIC-STRING> is a unique   identifier within the subnamespace identifier scope.   <SNID> has the same syntax as an <NID> as defined in [RFC2141].   SANA assigns SNIDs.   The syntax of <SUBNAMESPACE-SPECIFIC-STRING> is dependent on the   <SNID> and MUST be defined by a CCSDS document.  This document does   not pose any additional restrictions to the <SUBNAMESPACE-SPECIFIC-   STRING> other than what is defined in the NSS syntax as defined by   [RFC2141]:   SUBNAMESPACE-SPECIFIC-STRING = 1*<URN chars>   <URN chars> is defined inSection 2.2 of [RFC2141].3.5.  Relevant Ancillary Documentation   SANA keeps the "urn:ccsds" namespace as a registry [SANA-Reg].   Procedures to register a subnamespace identifier are described in the   header of the registry.3.6.  Identifier Uniqueness Considerations   SANA is the authority responsible for uniqueness of identifiers by   the recommendations of CCSDS.  SANA will assign unique identifiers   and keep a public registry [SANA-Reg].3.7.  Identifier Persistence Considerations   CCSDS is committed to guaranteeing the accessibility and persistence   of all the resources that are assigned URNs.Blanchet, et al.              Informational                     [Page 4]

RFC 7738                 URN Namespace for CCSDS            January 20163.8.  Process of Identifier Assignment   Assignment of identifiers is limited to CCSDS and those authorities   explicitly designated by CCSDS.  CCSDS is committed to assigning URN   identifiers only in accordance with the rules specified in this   document or in future updates to this document, either published as   IETF RFC documents or as CCSDS recommendations.3.9.  Process for Identifier Resolution   The CCSDS 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.3.10.  Rules for Lexical Equivalence   The <SNID> part of URNs in the CCSDS hierarchy is case insensitive.   Thus, the <SNID> MUST be case normalized before comparison.3.11.  Conformance with URN Syntax   The intention of this document is to only restrict the syntax of the   <SNID>.  The syntax of the <SUBNAMESPACE-SPECIFIC-STRING> follows the   general syntax of a URN:   SUBNAMESPACE-SPECIFIC-STRING = 1*<URN chars>   Documents defining a subnamespace identifier SHOULD specify further   syntactic restrictions in <SUBNAMESPACE-SPECIFIC-STRING>.  It is   RECOMMENDED that these documents forbid the assignment of URNs   containing characters in the <reserved> set ("%", "/", "?", and "#")   as defined in [RFC2141].  This is in accordance withSection 2.2 of   [RFC3986].3.12.  Validation Mechanism   The validation mechanism of URNs in the hierarchy is specific for   each SNID and SHOULD be defined when an SNID is assigned.   URNs in the hierarchy without an assigned SNID are considered to be   invalid.3.13.  Scope   Global URNs are relevant for the space agencies networks both in   space and on Earth.Blanchet, et al.              Informational                     [Page 5]

RFC 7738                 URN Namespace for CCSDS            January 20164.  Examples   URNs in this section are not guaranteed to be real and are listed   here only for illustration purposes.  The following are examples of   valid URNs for the "document" and "schema" categories:      urn:ccsds:document:313x0y1      urn:ccsds:schema:ndm:aem5.  Namespace Considerations   CCSDS is an international standards development organization in the   field of space and Earth communications.  The use of this URN   hierarchy is expected to be broad, including but not limited to usage   for:      CCSDS documents      XML Schemas      CCSDS registries   The CCSDS documents and registries are available openly.6.  Community Considerations   Usage of the URN namespace has been requested within the CCSDS   community for various projects.7.  Security Considerations   No additional security considerations are relevant, other than those   normally related with the general use and resolution of URNs.8.  IANA Considerations   IANA has registered the "ccsds" NID within the IANA registry of URN   NIDs in the "Formal URN Namespaces" subregistry.Blanchet, et al.              Informational                     [Page 6]

RFC 7738                 URN Namespace for CCSDS            January 20169.  References9.1.  Normative References   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate              Requirement Levels",BCP 14,RFC 2119,              DOI 10.17487/RFC2119, March 1997,              <http://www.rfc-editor.org/info/rfc2119>.   [RFC2141]  Moats, R., "URN Syntax",RFC 2141, DOI 10.17487/RFC2141,              May 1997, <http://www.rfc-editor.org/info/rfc2141>.   [RFC3406]  Daigle, L., van Gulik, D., Iannella, R., and P. Faltstrom,              "Uniform Resource Names (URN) Namespace Definition              Mechanisms",BCP 66,RFC 3406, DOI 10.17487/RFC3406,              October 2002, <http://www.rfc-editor.org/info/rfc3406>.   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform              Resource Identifier (URI): Generic Syntax", STD 66,RFC 3986, DOI 10.17487/RFC3986, January 2005,              <http://www.rfc-editor.org/info/rfc3986>.   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax              Specifications: ABNF", STD 68,RFC 5234,              DOI 10.17487/RFC5234, January 2008,              <http://www.rfc-editor.org/info/rfc5234>.9.2.  Informative References   [CCSDS]    CCSDS, "The Consultative Committee for Space Data              Systems", <http://www.ccsds.org/>.   [SANA]     SANA, "Space Assigned Numbers Authority",              <http://sanaregistry.org/>.   [SANA-Reg] SANA, "Space Assigned Number Authority (SANA) Registry",              <http://sanaregistry.org/r/urn>.Blanchet, et al.              Informational                     [Page 7]

RFC 7738                 URN Namespace for CCSDS            January 2016Acknowledgements   This document is based on previous draft versions authored by Martin   A. Soto and Louis Reich.  This document was reviewed by the XML   Steering Group (XSG) of the Systems Engineering and Architecture Area   (SEA) in CCSDS.Authors' Addresses   Marc Blanchet   Viagenie/SANA   246 Aberdeen   Quebec, QC  G1R 2E1   Canada   Email: Marc.Blanchet@viagenie.ca   URI:http://viagenie.ca   Audric Schiltknecht   Viagenie/SANA   246 Aberdeen   Quebec, QC  G1R 2E1   Canada   Email: audric.schiltknecht@viagenie.ca   URI:http://viagenie.ca   Peter Shames   Jet Propulsion Laboratory, NASA   Email: peter.m.shames@jpl.nasa.gov   URI:http://cwe.ccsds.org/sea/default.aspxBlanchet, et al.              Informational                     [Page 8]