draft-ietf-core-senml-versions-04.txt   draft-ietf-core-senml-versions-05.txt 
CoRE C. Bormann CoRE C. Bormann
Internet-Draft Universitaet Bremen TZI Internet-Draft Universitaet Bremen TZI
Updates: 8428 (if approved) 4 June 2021 Updates: 8428 (if approved) 4 June 2021
Intended status: Standards Track Intended status: Standards Track
Expires: 6 December 2021 Expires: 6 December 2021
SenML Features and Versions SenML Features and Versions
draft-ietf-core-senml-versions-04 draft-ietf-core-senml-versions-05
Abstract Abstract
This short document updates RFC 8428, Sensor Measurement Lists This short document updates RFC 8428, Sensor Measurement Lists
(SenML), by specifying the use of independently selectable "SenML (SenML), by specifying the use of independently selectable "SenML
Features" and mapping them to SenML version numbers. Features" and mapping them to SenML version numbers.
Discussion Venues Discussion Venues
This note is to be removed before publishing as an RFC. This note is to be removed before publishing as an RFC.
skipping to change at page 3, line 38 skipping to change at page 3, line 38
The present specification defines "SenML Features", each identified The present specification defines "SenML Features", each identified
by a "feature name" (a text string) and a "feature code" (an unsigned by a "feature name" (a text string) and a "feature code" (an unsigned
integer less than 53). integer less than 53).
The specific version of a SenML pack is composed of a set of The specific version of a SenML pack is composed of a set of
features. The SenML version number ("bver" field) is then a bitmap features. The SenML version number ("bver" field) is then a bitmap
of these features represented as an unsigned integer, specifically of these features represented as an unsigned integer, specifically
the sum of, for each feature present, two taken to the power of the the sum of, for each feature present, two taken to the power of the
feature code of that feature (Figure 1). feature code of that feature (Figure 1).
__ 52 fc __ 52 fc
version = \ present(fc) ⋅ 2 version = \ present(fc) ⋅ 2
/__ fc = 0 /__ fc = 0
Figure 1: Feature bitmap as a sum of feature bits Figure 1: Feature bitmap as a sum of feature bits
where present(fc) is 1 if the feature with the feature code "fc" is where present(fc) is 1 if the feature with the feature code "fc" is
present, 0 otherwise. (The expression 2^fc can be implemented as "1 present, 0 otherwise. (The expression 2^fc can be implemented as "1
<< fc" in C and related languages.) << fc" in C and related languages.)
RFC editor: Please check that, in the TXT version, no "&nbsp;" crept RFC editor: Please check that, in the TXT version, no "&nbsp;" crept
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