Internet Engineering Task Force (IETF) M. Blanchet Request for Comments: 7738 A. Schiltknecht Category: Informational Viagenie/SANA ISSN: 2070-1721 P. Shames Jet Propulsion Laboratory, NASA January 2016
A Uniform Resource Name (URN) Namespace for the 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; 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 http://www.rfc-editor.org/info/rfc7738.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved.
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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].
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].
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
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 in Section 2.2 of [RFC2141].
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.
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].
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.
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.
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 with Section 2.2 of [RFC3986].
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:
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.
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