Author: Jaime Jiménez
@due(27-12-14 15:28)
There are many types of more complex measurements and measurements that this media type would not be suitable for.
a concept of a
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:
[
{"n":"urn:dev:ow:10e2073a01080063","u":"Cel","v":23.1}
]
Multiple:
[
{"bn":"urn:dev:ow:10e2073a01080063:","n":"voltage","u":"V","v":120.1},
{"n":"current","u":"A","v":1.2}
]
Collections:
[
{"bn":"2001:db8::2/","bt":1.320078429e+09,
"n":"temperature","u":"Cel","v":25.2},
{"n":"humidity","u":"%RH","v":30},
{"bn":"2001:db8::1/","n":"temperature","u":"Cel","v":12.3},
{"n":"humidity","u":"%RH","v":67}
]
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:
coap://example.com/temp#rec=3,5
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].
[1] https://github.com/cisco/senml
[2] https://github.com/eclipse/leshan/tree/master/leshan-core/src/main/java/org/eclipse/leshan/json
[3] https://github.com/backenklee/RIOT/tree/senml-experimental
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.
The document has gone through multiple expert reviews and has been discussed on multiple IETF meetings. Before the last IETF the WGLC was completed.
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.
There are RFC Editor comments that need to be edited out. The document creates two new registries, a content type and various media types.
Does not apply
If this is a bis
document, have all of the errata been considered? Does not apply
IANA Considerations:
Are the IANA Considerations clear and complete? Remember that IANA have to understand unambiguously what’s being requested, so they can perform the required actions.
Q: Are the new media type IDs assigned sequentially or do we request something concrete to IANA? URL to check http://www.iana.org/assignments/core-parameters/core-parameters.xhtml
A: I think a sequence of 8 values starting from a round number (for easy mnemonic) would make sense. But could check with the experts what's the policy here
Are all protocol extensions that the document makes associated with the appropriate reservations in IANA registries?
Are all IANA registries referred to by their exact names (check them in http://www.iana.org/protocols/ to be sure)?
Have you checked that any registrations made by this document correctly follow the policies and procedures for the appropriate registries?I believe so, double check with Carsten on the new registries.
For registrations that require expert review (policies of Expert Review or Specification Required), have you or the working group had any early review done, to make sure the requests are ready for last call?
For any new registries that this document creates, has the working group actively chosen the allocation procedures and policies and discussed the alternatives?
Have reasonable registry names been chosen (that will not be confused with those of other registries), and have the initial contents and valid value ranges been clearly specified?