CoRE Target Attributes Registry

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Table of Contents

1. Introduction

The Constrained RESTful Environments (CoRE) specifications apply Web technologies to constrained environments. One important such technology is Web Linking [RFC8288], which CoRE specifications use as the basis for a number of discovery protocols, such as the Link Format [RFC6690] in CoAP's Resource Discovery Protocol (Section 7.2 of [RFC7252]) and the Resource Directory [RFC9176].¶

Web Links can have target attributes. The original Web Linking specification (Section 3 of [RFC5988]) did not attempt to coordinate names of target attributes except for providing common target attributes for use in the Link HTTP header. The current revision of that specification clarifies (Section 2.2 of [RFC8288]):¶

This specification does not attempt to coordinate the name of target attributes, their cardinality, or use. Those creating and maintaining serialisations SHOULD coordinate their target attributes to avoid conflicts in semantics or syntax and MAY define their own registries of target attributes.¶

This document introduces an IANA registry for coordinating names of target attributes when used in CoRE, with specific instructions for the Designated Expert for this registry (Section 2.1). It updates the RD Parameters IANA Registry created by [RFC9176] to coordinate with this registry.¶

With a registry now available, registration of target attributes is strongly encouraged. The incentive is that an unregistered attribute name might be registered with a different meaning at any time.¶

2. IANA Considerations

This specification creates a new Target Attributes registry in the "Constrained RESTful Environments (CoRE) Parameters" registry group [IANA.core-parameters], with the policy "Expert Review" (Section 4.5 of [BCP26]).¶

3. Security considerations

The security considerations of [RFC8288] apply, as do those of the discovery specifications [RFC6690], [RFC7252], and [RFC9176].¶

Acknowledgements

The CoRE WG had been discussing setting up a registry for target attributes since the final touches were made on [RFC6690]. The update of the Web Linking specification to [RFC8288] provided the formal setting, but it took until Jaime Jiménez provided the set of initial registrations to generate a first version of this specification. The current version addresses additional input and working group last call comments by Esko Dijk, Marco Tiloca, Thomas Fossati, and Mohamed Boucadair, as well as area director review comments from Rob Wilton.¶

Contributors

Jaime provided the list of initial registrations.¶

Author's Address