Status CoRE SenML

Author: Jaime Jiménez

Tentative Timeline

Comments to authors on v11


Summary draft-ietf-core-senml-12

Media Types for Sensor Markup Language (SenML)

The specification defines media types for representing simple sensor measurements in Sensor Measurement List (SenML). The draft explains the structure and semantics of SenML and how to represent it in its four serializations. It comes with 6 base fields:

Base values help compress the information not to repeat fields. Multiple measurements are taken in an incremental fashion adding to the base value. Similarly JSON, XML and CBOR labels help compress a bit more.It allows for representing measurements with individual and multiple datapoints, as well as various data types and collections.

Single datapoint:






It also allows for fragment record identifiers to select portions of a senml resource representation. For example the 3rd and 5th record can be selected with:


The draft also introduces CDDL descriptions for the JSON and CBOR representations as well as the CBOR labels.

There are several implementations available, Cisco’s [1], Leshan [2] and RIOT OS [3].




Shepherd Writeup


This specification defines media types for representing simple sensor measurements and device parameters in the Sensor Measurement Lists (SenML). Representations are defined in JavaScript Object Notation (JSON), Concise Binary Object Representation (CBOR), eXtensible Markup Language (XML), and Efficient XML Interchange (EXI), which share the common SenML data model. A simple sensor, such as a temperature sensor, could use this media type in protocols such as HTTP or CoAP to transport the measurements of the sensor or to be configured.

The document is intended for Standards Track.

Review and Consensus

The document has gone through multiple expert reviews and has been discussed on multiple IETF meetings. Before the last IETF the WGLC was completed.

Intellectual Property

Each author has stated that they do not have direct, personal knowledge of any IPR related to this document. I am not aware of any IPR discussion about this document on the CoRE WG.

Other Points

There are RFC Editor comments that need to be edited out. The document creates two new registries, a content type and various media types.