Internet-Draft | SDF Mapping | June 2024 |
Bormann & Romann | Expires 6 December 2024 | [Page] |
- Workgroup:
- ASDF
- Internet-Draft:
- draft-bormann-asdf-sdf-mapping-04
- Published:
- Intended Status:
- Standards Track
- Expires:
Semantic Definition Format (SDF): Mapping files
Abstract
The Semantic Definition Format (SDF) is a format for domain experts to use in the creation and maintenance of data and interaction models that describe Things, i.e., physical objects that are available for interaction over a network. It was created as a common language for use in the development of the One Data Model liaison organization (OneDM) models. Tools convert this format to database formats and other serializations as needed.¶
An SDF specification often needs to be augmented by additional information that is specific to its use in a particular ecosystem or application. SDF mapping files provide a mechanism to represent this augmentation.¶
About This Document
This note is to be removed before publishing as an RFC.¶
Status information for this document may be found at https://datatracker.ietf.org/doc/draft-bormann-asdf-sdf-mapping/.¶
Discussion of this document takes place on the A Semantic Definition Format for Data and Interactions of Things (asdf) Working Group mailing list (mailto:asdf@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/asdf/. Subscribe at https://www.ietf.org/mailman/listinfo/asdf/.¶
Source for this draft and an issue tracker can be found at https://github.com/cabo/sdf-mapping.¶
Status of This Memo
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This Internet-Draft will expire on 6 December 2024.¶
Copyright Notice
Copyright (c) 2024 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 (https://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 Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.¶
1. Introduction
The Semantic Definition Format (SDF) is a format for domain experts to use in the creation and maintenance of data and interaction models that describe Things, i.e., physical objects that are available for interaction over a network. It was created as a common language for use in the development of the One Data Model liaison organization (OneDM) models. Tools convert this format to database formats and other serializations as needed.¶
An SDF specification often needs to be augmented by additional information that is specific to its use in a particular ecosystem or application. SDF mapping files provide a mechanism to represent this augmentation.¶
1.1. Terminology and Conventions
The definitions of [I-D.ietf-asdf-sdf] apply.¶
The term "byte" is used in its now-customary sense as a synonym for "octet".¶
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶
2. Overview
An SDF mapping file provides augmentation information for one or more SDF models. Its main contents is a map from SDF name references (Section 4.3 of [I-D.ietf-asdf-sdf]) to a set of qualities.¶
When processing the mapping file together with one or more SDF
models, these qualities are added to the SDF model at the
referenced name, as in a merge-patch operation [RFC7396].
Note that this is somewhat similar to the way sdfRef
(Section 4.4 of [I-D.ietf-asdf-sdf]) works, but in a
mapping file the arrows point in the inverse direction (from the
augmenter to the augmented).¶
2.1. Example Model 1 (ecosystem: IPSO/OMA)
An example for an SDF mapping file is given in Figure 1.
This mapping file is meant to attach to an SDF specification published
by OneDM, and to add qualities relevant to the IPSO/OMA ecosystem.
Note that this example uses namespaces to identify elements of the
referenced specification(s), but has un-namespaced quality names.
These two kinds of namespaces are probably unrelated, and we may
need to add quality namespacing to SDF (independent of a potential
feature to add namespace references to definitions that are not
intended to go into the default namespace — these are SDF
definition namespaces and not quality namespaces, which are one
meta-level higher).¶
-
Start of mapping file for certain OneDM playground models:¶
2.2. Example Model 2 (ecosystem: W3C WoT)
This example shows a translation of a hypothetical W3C WoT Thing Model
into an SDF model plus a mapping file to catch Thing Model attributes
that don't currently have SDF qualities defined.
The example probably would be more useful with, say, protocol
bindings.
This is left for a future version of this example, and/or a
future specification that specifically addresses how to map Thing
Models into SDF.
(There is also the separate requirement to transform a Thing Description
into the kind of information that can be represented in SDF plus
instance information, such as IP addresses or specific node
names.)
Finally, namespaces are all wrong in this example.¶
-
The input: WoT Thing Model¶
-
The output: SDF model¶
-
The other output: SDF mapping file¶
3. Formal Syntax of SDF mapping files
An SDF mapping file has three optional components that are taken unchanged from SDF: The info block, the namespace declaration, and the default namespace. The mandatory fourth component, the "map", contains the mappings from an SDF name reference (usually a namespace and a JSON pointer) to a nested map providing a set of qualities to be merged in at the site identified in the name reference.¶
Figure 5 describes the syntax of SDF mapping files using CDDL [RFC8610].¶
4. IANA Considerations
4.1. Media Type
IANA is requested to add the following Media-Type to the "Media Types" registry.¶
Name | Template | Reference |
---|---|---|
sdf-mapping+json | application/sdf-mapping+json | RFC XXXX, Section 4.1 |
RFC Editor: please replace RFC XXXX with this RFC number and remove this note.¶
- Type name:
-
application¶
- Subtype name:
-
sdf-mapping+json¶
- Required parameters:
-
none¶
- Optional parameters:
-
none¶
- Encoding considerations:
-
binary (JSON is UTF-8-encoded text)¶
- Security considerations:
- Interoperability considerations:
-
none¶
- Published specification:
-
Section 4.1 of RFC XXXX¶
- Applications that use this media type:
-
Tools for data and interaction modeling that describes Things, i.e., physical objects that are available for interaction over a network¶
- Fragment identifier considerations:
-
A JSON Pointer fragment identifier may be used, as defined in Section 6 of [RFC6901].¶
- Person & email address to contact for further information:
-
ASDF WG mailing list (asdf@ietf.org), or IETF Applications and Real-Time Area (art@ietf.org)¶
- Intended usage:
-
COMMON¶
- Restrictions on usage:
-
none¶
- Author/Change controller:
-
IETF¶
- Provisional registration:
-
no¶
4.2. Registries
(TBD: After any future additions, check if we need any.)¶
5. Security Considerations
Some wider issues are discussed in [RFC8576].¶
(Specifics: TBD.)¶
6. References
6.1. Normative References
- [I-D.ietf-asdf-sdf]
- Koster, M., Bormann, C., and A. Keränen, "Semantic Definition Format (SDF) for Data and Interactions of Things", Work in Progress, Internet-Draft, draft-ietf-asdf-sdf-18, , <https://datatracker.ietf.org/doc/html/draft-ietf-asdf-sdf-18>.
- [RFC2119]
- Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/rfc/rfc2119>.
- [RFC6901]
- Bryan, P., Ed., Zyp, K., and M. Nottingham, Ed., "JavaScript Object Notation (JSON) Pointer", RFC 6901, DOI 10.17487/RFC6901, , <https://www.rfc-editor.org/rfc/rfc6901>.
- [RFC7396]
- Hoffman, P. and J. Snell, "JSON Merge Patch", RFC 7396, DOI 10.17487/RFC7396, , <https://www.rfc-editor.org/rfc/rfc7396>.
- [RFC8174]
- Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/rfc/rfc8174>.
- [RFC8610]
- Birkholz, H., Vigano, C., and C. Bormann, "Concise Data Definition Language (CDDL): A Notational Convention to Express Concise Binary Object Representation (CBOR) and JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610, , <https://www.rfc-editor.org/rfc/rfc8610>.
6.2. Informative References
- [RFC8576]
- Garcia-Morchon, O., Kumar, S., and M. Sethi, "Internet of Things (IoT) Security: State of the Art and Challenges", RFC 8576, DOI 10.17487/RFC8576, , <https://www.rfc-editor.org/rfc/rfc8576>.
Acknowledgements
This draft is based on discussions in the Thing-to-Thing Research Group (T2TRG) and the SDF working group. Input for Section 2.1 was provided by Ari Keränen.¶