SenML Data Value Content-Format Indication
draft-keranen-core-senml-data-ct-00

The information below is for an old version of the document
Document Type Active Internet-Draft (individual)
Last updated 2019-02-11
Stream (None)
Intended RFC status (None)
Formats plain text pdf html bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
Network Working Group                                         A. Keranen
Internet-Draft                                                  Ericsson
Intended status: Standards Track                              C. Bormann
Expires: August 15, 2019                         Universitaet Bremen TZI
                                                       February 11, 2019

               SenML Data Value Content-Format Indication
                  draft-keranen-core-senml-data-ct-00

Abstract

   The Sensor Measurement Lists (SenML) media type supports multiple
   types of values, from numbers to text strings and arbitrary binary
   data values.  In order to simplify processing of the data values this
   document proposes to specify a new SenML field for indicating the
   Content-Format of the data.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on August 15, 2019.

Copyright Notice

   Copyright (c) 2019 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 Simplified BSD License text as described in Section 4.e of

Keranen & Bormann        Expires August 15, 2019                [Page 1]
Internet-Draft SenML Data Value Content-Format Indication  February 2019

   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  SenML Content-Format Field ("ct") . . . . . . . . . . . . . .   3
   4.  SenML Base Content-Format Field ("bct") . . . . . . . . . . .   3
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   4
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   The Sensor Measurement Lists (SenML) media type [RFC8428] can be used
   to send various different kinds of data.  In the example given in
   Figure 1, a temperature value, an indication whether a lock is open,
   and a data value (with SenML field "vd") read from an NFC reader is
   sent in a single SenML pack.

  [
    {"bn":"urn:dev:ow:10e2073a01080063:","n":"temp","u":"Cel","v":23.1},
    {"n":"open","vb":false},
    {"n":"nfc-reader","vd":"aGkgCg"}
  ]

            Figure 1: SenML pack with unidentified binary data

   The receiver is expected to know how to decode the data in the "vd"
   field based on the context, e.g., name of the data source and out-of-
   band knowledge of the application.  However, this context may not
   always be easily available to entities processing the SenML pack.  To
   facilitate automatic decoding it is useful to be able to indicate an
   Internet media type and content-coding right in the SenML Record.
   The CoAP Content-Format (Section 12.3 in [RFC7252]) provides just
   this information; enclosing a Content-Format number (in this case
   number 60 as defined for media type application/cbor in [RFC7049]) in
   the Record is illustrated in Figure 2.

   {"n":"nfc-reader", "vd":"gmNmb28YKg", "ct":60}

        Figure 2: SenML Record with binary data identified as CBOR

Keranen & Bormann        Expires August 15, 2019                [Page 2]
Internet-Draft SenML Data Value Content-Format Indication  February 2019

   In this example SenML Record the data value contains a string "foo"
   and a number 42 encoded in a CBOR [RFC7049] array.  Since the example
   above uses the JSON format of SenML, the data value containing the
   binary CBOR value is base64-encoded.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
Show full document text