rfc9581.original.xml   rfc9581.xml 
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<rfc xmlns:xi="http://www.w3.org/2001/XInclude" category="std" consensus="true" std" consensus="true" docName="draft-ietf-cbor-time-tag-12" number="9581" ipr="t
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<front> <front>
<title abbrev="CBOR tag for extended time">Concise Binary Object Representat <title abbrev="CBOR Tag for Extended Time">Concise Binary Object Representat
ion (CBOR) Tags for Time, Duration, and Period</title> ion (CBOR) Tags for Time, Duration, and Period</title>
<seriesInfo name="Internet-Draft" value="draft-ietf-cbor-time-tag-12"/> <seriesInfo name="RFC" value="9581"/>
<author fullname="Carsten Bormann" initials="C." surname="Bormann"> <author fullname="Carsten Bormann" initials="C." surname="Bormann">
<organization>Universität Bremen TZI</organization> <organization>Universität Bremen TZI</organization>
<address> <address>
<postal> <postal>
<street>Postfach 330440</street> <street>Postfach 330440</street>
<city>Bremen</city> <city>Bremen</city>
<code>D-28359</code> <code>D-28359</code>
<country>Germany</country> <country>Germany</country>
</postal> </postal>
<phone>+49-421-218-63921</phone> <phone>+49-421-218-63921</phone>
skipping to change at line 52 skipping to change at line 52
</author> </author>
<author fullname="Henk Birkholz" initials="H." surname="Birkholz"> <author fullname="Henk Birkholz" initials="H." surname="Birkholz">
<organization abbrev="Fraunhofer SIT">Fraunhofer Institute for Secure Info rmation Technology</organization> <organization abbrev="Fraunhofer SIT">Fraunhofer Institute for Secure Info rmation Technology</organization>
<address> <address>
<postal> <postal>
<street>Rheinstrasse 75</street> <street>Rheinstrasse 75</street>
<city>Darmstadt</city> <city>Darmstadt</city>
<code>64295</code> <code>64295</code>
<country>Germany</country> <country>Germany</country>
</postal> </postal>
<email>henk.birkholz@sit.fraunhofer.de</email> <email>henk.birkholz@ietf.contact</email>
</address> </address>
</author> </author>
<date year="2023"/> <date year="2024" month="June"/>
<keyword>Internet-Draft</keyword> <area>art</area>
<workgroup>cbor</workgroup>
<keyword>Point in time</keyword>
<keyword>Duration</keyword>
<keyword>Period in time</keyword>
<keyword>Clock accuracy</keyword>
<keyword>Timescale</keyword>
<keyword>TAI</keyword>
<keyword>UTC</keyword>
<keyword>NTP</keyword>
<keyword>Network Time Protocol</keyword>
<keyword>PTP</keyword>
<keyword>Precision Time Protocol</keyword>
<abstract> <abstract>
<?line 167?> <?line 167?>
<t>The Concise Binary Object Representation (CBOR, RFC 8949) is a data <t>The Concise Binary Object Representation (CBOR, RFC 8949) is a data
format whose design goals include the possibility of extremely small format whose design goals include the possibility of extremely small
code size, fairly small message size, and extensibility without the code size, fairly small message size, and extensibility without the
need for version negotiation.</t> need for version negotiation.</t>
<t>In CBOR, one point of extensibility is the definition of CBOR tags. <t>In CBOR, one point of extensibility is the definition of CBOR tags.
RFC 8949 defines two tags for time: CBOR tag 0 (RFC3339 time as a string) and ta g RFC 8949 defines two tags for time: CBOR tag 0 (RFC 3339 time as a string) and t ag
1 (POSIX time as int or float). Since then, additional requirements have 1 (POSIX time as int or float). Since then, additional requirements have
become known. The present document defines a CBOR tag for time that become known. The present document defines a CBOR tag for time that
allows a more elaborate representation of time, as well as related allows a more elaborate representation of time, as well as related
CBOR tags for duration and time period. This document is CBOR tags for duration and time period. This document is
intended as the reference document for the IANA registration of the intended as the reference document for the IANA registration of the
CBOR tags defined.</t> CBOR tags defined.</t>
<t><cref anchor="status">(This cref will be removed by the RFC editor:)<br
/>
The present revision (–12) addresses the IESG reviews.</cref></t>
</abstract> </abstract>
<note removeInRFC="true">
<name>About This Document</name>
<t>
Status information for this document may be found at <eref target="https
://datatracker.ietf.org/doc/draft-ietf-cbor-time-tag/"/>.
</t>
<t>
Discussion of this document takes place on the
CBOR Working Group mailing list (<eref target="mailto:cbor@ietf.org"/>),
which is archived at <eref target="https://mailarchive.ietf.org/arch/bro
wse/cbor/"/>.
Subscribe at <eref target="https://www.ietf.org/mailman/listinfo/cbor/"/
>.
</t>
<t>Source for this draft and an issue tracker can be found at
<eref target="https://github.com/cbor-wg/time-tag"/>.</t>
</note>
</front> </front>
<middle> <middle>
<?line 191?> <?line 191?>
<section anchor="intro"> <section anchor="intro">
<name>Introduction</name> <name>Introduction</name>
<t>The Concise Binary Object Representation (CBOR, <xref target="RFC8949"/ >) provides <t>The Concise Binary Object Representation (CBOR) <xref target="RFC8949"/ > provides
for the interchange of structured data without a requirement for a for the interchange of structured data without a requirement for a
pre-agreed schema. pre-agreed schema.
RFC 8949 defines a basic set of data types, as well as a tagging RFC 8949 defines a basic set of data types, as well as a tagging
mechanism that enables extending the set of data types supported via mechanism that enables extending the set of data types supported via
an IANA registry for CBOR tags (<xref section="9.2" sectionFormat="of" target="R an IANA registry for CBOR tags (see <xref target="IANA.cbor-tags"/> and <xref se
FC8949"/>, <xref target="IANA.cbor-tags"/>).</t> ction="9.2" sectionFormat="of" target="RFC8949"/>).</t>
<t>RFC 8949 defines two tags for time: CBOR tag 0 (RFC3339 time as a strin <t>RFC 8949 defines two tags for time: CBOR tag 0 (<xref target="RFC3339"/
g) and tag > time as a string) and tag
1 (POSIX time as int or float). Since then, additional requirements have 1 (POSIX time as int or float). Since then, additional requirements have
become known. The present document defines a CBOR tag for time that become known. The present document defines a CBOR tag for time that
allows a more elaborate representation of time, as well as related allows a more elaborate representation of time, as well as related
CBOR tags for duration and time period. This document is CBOR tags for durations and time periods. This document is
intended as the reference document for the IANA registration of the intended as the reference document for the IANA registration of the
CBOR tags defined.</t> CBOR tags defined.</t>
<section anchor="terms"> <section anchor="terms">
<name>Terminology</name> <name>Terminology</name>
<t>The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp <t>
14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>",
NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>RECO "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL NOT</bcp14>
MMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>", ",
"<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are to be i "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>",
nterpreted as "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
described in BCP 14 <xref target="RFC2119"/> <xref target="RFC8174"/> when, and "<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are to
only when, they be
appear in all capitals, as shown here.</t> interpreted as described in BCP&nbsp;14 <xref target="RFC2119"/> <xref
target="RFC8174"/> when, and only when, they appear in all capitals, as
shown here.
</t>
<?line -18?> <?line -18?>
<t>The term "byte" is used in its now customary sense as a synonym for <t>The term "byte" is used in its now customary sense as a synonym for
"octet".</t> "octet".</t>
<t>Superscript notation denotes exponentiation. For example, 2 to the <t>Superscript notation denotes exponentiation. For example, 2 to the
power of 64 is notated: 2<sup>64</sup>. In the plain-text rendition power of 64 is notated: 2<sup>64</sup>. In the plain-text rendition
of this specification, superscript notation is not available and of this specification, superscript notation is not available and
exponentiation therefore is rendered by the surrogate notation seen exponentiation is therefore rendered by the surrogate notation seen
here in the plain-text rendition.</t> here in the plain-text rendition.</t>
<t>CBOR diagnostic notation is defined in <xref section="8" sectionForma t="of" target="RFC8949"/> and <t>CBOR diagnostic notation is defined in <xref section="8" sectionForma t="of" target="RFC8949"/> and
<xref section="G" sectionFormat="of" target="RFC8610"/>. <xref section="G" sectionFormat="of" target="RFC8610"/>.
A machine-processable model of the data structures defined in this A machine-processable model of the data structures defined in this
specification is provided throughout the text using the Concise Data specification is provided throughout the text using the Concise Data
Definition Language, CDDL <xref target="RFC8610"/>; <xref target="collected-cddl "/> provides the Definition Language (CDDL) <xref target="RFC8610"/>; <xref target="collected-cdd l"/> provides the
collected model information.</t> collected model information.</t>
<t>Several time-related terms such as UTC and TAI are discussed in <t>Several time-related terms, such as UTC and International Atomic Time
<xref target="IXDTF"/>, which may be a useful companion document beyond its dire (TAI), are discussed in
ct <xref target="RFC9557"/>, which may be a useful companion document beyond its di
rect
use in Sections <xref format="counter" target="tzh"/> and <xref format="counter" target="suff"/>.</t> use in Sections <xref format="counter" target="tzh"/> and <xref format="counter" target="suff"/>.</t>
</section> </section>
</section> </section>
<section anchor="objectives"> <section anchor="objectives">
<name>Objectives</name> <name>Objectives</name>
<t>For the time tag, <t>For the time tag,
the present specification addresses the following objectives that go the present specification addresses the following objectives that go
beyond the original tags 0 and 1 (defined in Sections <xref section="3.4.1" sect ionFormat="bare" target="RFC8949"/> and <xref section="3.4.2" sectionFormat="bar e" target="RFC8949"/> of <xref target="RFC8949"/>):</t> beyond the original tags 0 and 1 (defined in Sections <xref section="3.4.1" sect ionFormat="bare" target="RFC8949"/> and <xref section="3.4.2" sectionFormat="bar e" target="RFC8949"/> of <xref target="RFC8949"/>):</t>
<ul spacing="normal"> <ul spacing="normal">
<li> <li>
<t>Additional resolution for epoch-based time (as in tag 1). CBOR tag <t>Additional resolution for epoch-based time (as in tag 1). CBOR tag
1 only provides for integer and up to binary64 floating point 1 only provides for representation of time as an integer and as up to a binary64
representation of times, limiting resolution to approximately floating-point value <xref target="IEEE754"/>, which limits the resolution to a
pproximately
microseconds at the time of writing (and progressively becoming microseconds at the time of writing (and progressively becoming
worse over time).</t> worse over time).</t>
</li> </li>
<li> <li>
<t>Indication of timescale. Tags 0 and 1 are defined for UTC; however , some <t>Indication of timescale. Tags 0 and 1 are defined for UTC; however , some
interchanges are better performed on TAI. Other timescales may be interchanges are better performed on TAI. Other timescales may be
registered once they become relevant (e.g., one of the proposed registered once they become relevant (e.g., one of the proposed
successors to UTC that might no longer use leap seconds, or a successors to UTC that might no longer use leap seconds or a
scale based on smeared leap seconds).</t> scale based on smeared leap seconds).</t>
</li> </li>
</ul> </ul>
<t>By incorporating a way to transport <xref target="IXDTF"/> suffix infor
mation (<xref target="tzh"/>, <t>By incorporating a way to transport <xref target="RFC9557"/> suffix inf
<xref target="suff"/>), additional indications can be provided of intents about ormation (see Sections <xref target="tzh" format="counter"/> and
the <xref target="suff" format="counter"/>), additional indications of intents about
interpretation of the time given, in particular also for instances of the
interpretation of the time given can be provided; in particular, for instances o
f
time that, at the time they are being described, are in the future. time that, at the time they are being described, are in the future.
Intents might include information about time zones, daylight savings Intents might include information about time zones, daylight saving
times, preferred calendar representations, etc.</t> times, preferred calendar representations, etc.</t>
<t>Semantics not covered by this document can be added by registering <t>Semantics not covered by this document can be added by registering
additional map keys for the map that is the content of the tag (see additional map keys for the map that is the content of the tag (see
<tt>etime-detailed</tt> in <xref target="tag-1001"/>), <tt>etime-detailed</tt> in <xref target="tag-1001"/>),
the specification for the specification for
which is referenced by the registry entry (see <xref target="time-format"/>).</t > which is referenced by the registry entry (see <xref target="time-format"/>).</t >
<t>For example, map keys could be registered for direct representations <t>For example, map keys could be registered for direct representations
of natural platform time formats. Some platforms use epoch-based of natural platform time formats. Some platforms use epoch-based
time formats that require some computation to convert them into the time formats that require some computation to convert them into the
representations allowed by tag 1; these computations can also lose representations allowed by tag 1; these computations can also lose
precision and cause ambiguities. (The present specification does precision and cause ambiguities. (The present specification does
not take a position on whether tag 1 can be "fixed" to include, not take a position on whether tag 1 can be "fixed" to include,
e.g., Decimal or BigFloat representations. It does define how to e.g., Decimal or Bigfloat representations. It does define how to
use these representations with the extended time format.)</t> use these representations with the extended time format.)</t>
<t>Additional tags are defined for durations and periods.</t> <t>Additional tags are defined for durations and periods.</t>
</section> </section>
<section anchor="time-format"> <section anchor="time-format">
<name>Time Format</name> <name>Time Format</name>
<t>An extended time is indicated by CBOR tag 1001, the content of which is a map data <t>An extended time is indicated by CBOR tag 1001, the content of which is a map data
item (CBOR major type 5). The map may contain integer (major types 0 item (CBOR major type 5). The map may contain integer (major types 0
and 1) or text string (major type 3) keys, with the value type and 1) or text string (major type 3) keys, with the value type
determined by each specific key. determined by each specific key.
For negative integer keys and text string values of the key, For negative integer keys and text string values of the key,
implementations <bcp14>MUST</bcp14> ignore key/value pairs they do not understan d; implementations <bcp14>MUST</bcp14> ignore key/value pairs they do not understan d;
these keys are "elective", as the extended time as a whole is still these keys are "elective", as the extended time as a whole is still
usable without the information they carry if an implementation elects not to imp usable without the information they carry if an implementation elects not to imp
lement them. lement them. Conversely, implementations <bcp14>MUST</bcp14> signal an error
Conversely, for unsigned integer keys, implementations <bcp14>MUST</bcp14> signa when encountering key/value pairs that use unsigned integer keys they do not und
l as erstand or implement (these
an error key/value pairs they do not understand or implement are either "base time" or "critical", see below).</t>
(these are either "base time" or "critical", see below).</t>
<t>The map <bcp14>MUST</bcp14> contain exactly one unsigned integer key th at specifies <t>The map <bcp14>MUST</bcp14> contain exactly one unsigned integer key th at specifies
the "base time", and <bcp14>MAY</bcp14> also contain one or more negative intege r or the "base time" and <bcp14>MAY</bcp14> also contain one or more negative integer or
text-string keys, which may encode supplementary information.</t> text-string keys, which may encode supplementary information.</t>
<t>Supplementary information <bcp14>MAY</bcp14> also be provided by additi onal unsigned <t>Supplementary information <bcp14>MAY</bcp14> also be provided by additi onal unsigned
integer keys that are explicitly defined to provide supplementary integer keys that are explicitly defined to provide supplementary
information (we say these keys are defined to be "critical"); as these information (we say these keys are defined to be "critical"); as these
are required to be understood, there can be no confusion with base are required to be understood, there can be no confusion with base
time keys.</t> time keys.</t>
<t>Negative integer and text string keys always supply supplementary <t>Negative integer and text string keys always supply supplementary
information (they are "elective", and this will not be explicitly stated information (they are "elective", and this will not be explicitly stated
below).</t> below).</t>
<t>Supplementary information may include:</t> <t>Supplementary information may include:</t>
<ul spacing="normal"> <ul spacing="normal">
<li> <li>
<t>a higher precision time offset to be added to the base time,</t> <t>a higher precision time offset to be added to the base time,</t>
</li> </li>
<li> <li>
<t>a reference timescale and epoch different from the default UTC and 1970-01-01</t> <t>a reference timescale and epoch different from the default UTC and 1970-01-01, and</t>
</li> </li>
<li> <li>
<t>information about clock quality parameters, such as source, <t>information about clock quality parameters, such as source,
accuracy, and uncertainty</t> accuracy, and uncertainty.</t>
</li> </li>
</ul> </ul>
<t>Additional keys can be defined by registering them in the Map Key <t>Additional keys can be defined by registering them in the "Time Tag Map
Registry (<xref target="map-key-registry"/>). Keys"
Registered keys may, for instance, add intent information such as timezone and d registry (<xref target="map-key-registry"/>).
aylight savings time, Registered keys may, for instance, add intent information such as time zone, day
and/or possibly positioning coordinates, to express information that would indic light saving time,
ate a local time.</t> and/or possibly positioning coordinates to express information that would indica
te a local time.</t>
<t>This document does not define supplementary text keys. <t>This document does not define supplementary text keys.
A number of both unsigned and negative-integer keys are defined in A number of both unsigned and negative-integer keys are defined in
the following subsections.</t> the following subsections.</t>
<t><xref target="tag-1001"/> provides a formal definition of Tag 1001 in C DDL.</t> <t><xref target="tag-1001"/> provides a formal definition of tag 1001 in C DDL.</t>
<figure anchor="tag-1001"> <figure anchor="tag-1001">
<name>CDDL definition of Tag 1001</name> <name>CDDL Definition of Tag 1001</name>
<sourcecode type="cddl"><![CDATA[ <sourcecode type="cddl"><![CDATA[
Etime = #6.1001(etime-detailed) Etime = #6.1001(etime-detailed)
etime-framework = { etime-framework = {
uint => any ; at least one base time uint => any ; at least one base time
* (nint/text) => any ; elective supplementary information * (nint/text) => any ; elective supplementary information
* uint => any ; critical supplementary information * uint => any ; critical supplementary information
} }
etime-detailed = ({ etime-detailed = ({
skipping to change at line 267 skipping to change at line 268
defined for CBOR tag 4 or 5, respectively. defined for CBOR tag 4 or 5, respectively.
This can be used to include a Decimal or Bigfloat epoch-based float This can be used to include a Decimal or Bigfloat epoch-based float
<xref target="TIME_T"/> in an extended time, e.g., to achieve higher resolution or to <xref target="TIME_T"/> in an extended time, e.g., to achieve higher resolution or to
avoid rounding errors.</t> avoid rounding errors.</t>
<sourcecode type="cddl"><![CDATA[ <sourcecode type="cddl"><![CDATA[
$$ETIME-BASETIME //= (4: ~decfrac) $$ETIME-BASETIME //= (4: ~decfrac)
$$ETIME-BASETIME //= (5: ~bigfloat) $$ETIME-BASETIME //= (5: ~bigfloat)
]]></sourcecode> ]]></sourcecode>
</section> </section>
<section anchor="keys-3-6-9-12-15-18"> <section anchor="keys-3-6-9-12-15-18">
<name>Keys -3, -6, -9, -12, -15, -18</name> <name>Keys -3, -6, -9, -12, -15, and -18</name>
<t>The keys -3, -6, -9, -12, -15 and -18 indicate additional decimal fra <t>The keys -3, -6, -9, -12, -15, and -18 indicate additional decimal fr
ctions by actions by
giving an unsigned integer (major type 0) and scaling this with the giving an unsigned integer (major type 0) and scaling this with the
scale factor 1e-3, 1e-6, 1e-9, 1e-12, 1e-15, and 1e-18, respectively scale factor 1e-3, 1e-6, 1e-9, 1e-12, 1e-15, and 1e-18, respectively
(see <xref target="decfract"/>). (see <xref target="decfract"/>).
Each extended time data item <bcp14>MUST NOT</bcp14> contain more than one Each extended time data item <bcp14>MUST NOT</bcp14> contain more than one
of these keys. of these keys.
These additional fractions are added to a base time in seconds <xref target="SI- SECOND"/> These additional fractions are added to a base time in seconds <xref target="SI- SECOND"/>
indicated by a Key 1, which then <bcp14>MUST</bcp14> also be present and <bcp14> MUST</bcp14> have an indicated by key 1, which then <bcp14>MUST</bcp14> also be present and <bcp14>MU ST</bcp14> have an
integer value.</t> integer value.</t>
<table anchor="decfract"> <table anchor="decfract">
<name>Key for decimally scaled Fractions</name> <name>Keys for Decimally Scaled Fractions</name>
<thead> <thead>
<tr> <tr>
<th align="left">Key</th> <th align="left">Key</th>
<th align="left">meaning</th> <th align="left">Meaning</th>
<th align="left">example usage</th> <th align="left">Example Usage</th>
</tr> </tr>
</thead> </thead>
<tbody> <tbody>
<tr> <tr>
<td align="left">-3</td> <td align="left">-3</td>
<td align="left">milliseconds</td> <td align="left">milliseconds</td>
<td align="left">Java time</td> <td align="left">Java time</td>
</tr> </tr>
<tr> <tr>
<td align="left">-6</td> <td align="left">-6</td>
skipping to change at line 332 skipping to change at line 333
$$ETIME-ELECTIVE //= (-9: uint) $$ETIME-ELECTIVE //= (-9: uint)
$$ETIME-ELECTIVE //= (-12: uint) $$ETIME-ELECTIVE //= (-12: uint)
$$ETIME-ELECTIVE //= (-15: uint) $$ETIME-ELECTIVE //= (-15: uint)
$$ETIME-ELECTIVE //= (-18: uint) $$ETIME-ELECTIVE //= (-18: uint)
]]></sourcecode> ]]></sourcecode>
<t>Note that these keys have been provided to facilitate representing <t>Note that these keys have been provided to facilitate representing
pairs of the form second/decimal fraction of a second, as found for pairs of the form second/decimal fraction of a second, as found for
instance in C <tt>timespec</tt> (Section 7.27.1 of <xref target="C"/>). instance in C <tt>timespec</tt> (Section 7.27.1 of <xref target="C"/>).
When ingesting a timestamp with one of these keys into a type provided When ingesting a timestamp with one of these keys into a type provided
by the target platform, care has to be taken to meet its invariants. by the target platform, care has to be taken to meet its invariants.
E.g., for C <tt>timespec</tt>, the fractional part <tt>tv_nsec</tt> needs to be For example, for C <tt>timespec</tt>, the fractional part <tt>tv_nsec</tt> needs to be
between 0 inclusive and 10<sup>9</sup> exclusive, which can be between 0 inclusive and 10<sup>9</sup> exclusive, which can be
achieved by also adjusting the base time appropriately.</t> achieved by also adjusting the base time appropriately.</t>
</section> </section>
<section anchor="key-timescale"> <section anchor="key-timescale">
<name>Key -1: Timescale</name> <name>Keys -1, -13, and 13: Timescale</name>
<t>Key -1 is used to indicate a timescale. The value 0 indicates UTC, <t>Keys -1, -13, and 13 are used to indicate a timescale, where key 13 i
s critical. Keys -1 and -13 have identical semantics (they are both assigned bec
ause
key -1 was chosen first and then, when key 13 was added, it appeared desirable
to have a
negative equivalent).
Each extended time data item <bcp14>MUST NOT</bcp14>
contain more than one of these keys.</t>
<t>The value 0 indicates UTC,
with the POSIX epoch <xref target="TIME_T"/>; the value 1 indicates TAI, with th e with the POSIX epoch <xref target="TIME_T"/>; the value 1 indicates TAI, with th e
PTP (Precision Time Protocol) epoch (1 January 1970 00:00:00 TAI, see Precision Time Protocol (PTP) epoch (1 January 1970 00:00:00 TAI, see
<xref target="IEEE1588-2019"/> or <xref target="IEEE1588-2008"/>).</t> <xref target="IEEE1588-2019"/> or <xref target="IEEE1588-2008"/>).</t>
<sourcecode type="cddl"><![CDATA[ <sourcecode type="cddl"><![CDATA[
$$ETIME-ELECTIVE //= (-1 => $ETIME-TIMESCALE) $$ETIME-ELECTIVE //= (-1 => $ETIME-TIMESCALE)
$$ETIME-ELECTIVE //= (-13 => $ETIME-TIMESCALE)
$$ETIME-CRITICAL //= (13 => $ETIME-TIMESCALE)
$ETIME-TIMESCALE /= &(etime-utc: 0) $ETIME-TIMESCALE /= &(etime-utc: 0)
$ETIME-TIMESCALE /= &(etime-tai: 1) $ETIME-TIMESCALE /= &(etime-tai: 1)
]]></sourcecode> ]]></sourcecode>
<t>If key -1 is not present, the default timescale value 0 is implied.</ t> <t>If none of the keys are present, the default timescale value 0 is imp lied.</t>
<t>Timescale values <bcp14>MUST</bcp14> be unsigned integers or text str ings; text strings are <t>Timescale values <bcp14>MUST</bcp14> be unsigned integers or text str ings; text strings are
provided for experimentation and <bcp14>MUST NOT</bcp14> be used between parties provided for experimentation and <bcp14>MUST NOT</bcp14> be used between parties
which are not both part of the experiment. that are not both part of the experiment.
Additional unsigned integer values can be registered in the Timescale Registry Additional unsigned integer values can be registered in the "Timescales" registr
y
(<xref target="timescale-registry"/>). (<xref target="timescale-registry"/>).
(Note that there should be no timescales "GPS" or "NTP" <xref target="RFC5905"/> — instead, (Note that there should be no timescales "GPS" or "NTP" <xref target="RFC5905"/> -- instead,
the time should be converted to TAI or UTC using a single addition or subtractio n.)</t> the time should be converted to TAI or UTC using a single addition or subtractio n.)</t>
<figure anchor="offset"> <figure anchor="offset">
<name>Converting Common Offset Timescales</name> <name>Converting Common Offset Timescales</name>
<artset> <artset>
<artwork type="svg"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" height="6.009ex" role="img" viewBox="0 -791.3 43055.4 2587.3" width="100ex"> <artwork type="svg"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" height="6.009ex" role="img" viewBox="0 -791.3 43055.4 2587.3" width="100ex">
<defs> <defs>
<path d="M283 438l-10 -38h-70l-78 -320c-1 -3 -2 -8 -2 -11c0 -6 3 -12 16 -12c0 0 23 2 60 52l13 -11c-24 -31 -74 -107 -133 -107c-31 0 -39 25 -39 52c0 13 2 26 5 37l81 320h-77l5 29c75 14 136 51 177 138h13l-31 -129h70Z" id="E1-S TIXWEBNORMALI-1D461-gensym001" stroke-width="1"/> <path d="M283 438l-10 -38h-70l-78 -320c-1 -3 -2 -8 -2 -11c0 -6 3 -12 16 -12c0 0 23 2 60 52l13 -11c-24 -31 -74 -107 -133 -107c-31 0 -39 25 -39 52c0 13 2 26 5 37l81 320h-77l5 29c75 14 136 51 177 138h13l-31 -129h70Z" id="E1-S TIXWEBNORMALI-1D461-gensym001" stroke-width="1"/>
<path d="M444 428l-89 -348c-1 -4 -1 -6 -1 -9c0 -8 4 -14 14 -14 c21 0 40 26 57 46l5 6l13 -11c-23 -33 -74 -107 -132 -107c-29 0 -40 19 -40 52c0 9 1 25 4 37l26 95h-1c-7 -5 -97 -126 -137 -156c-23 -17 -49 -28 -72 -28c-47 0 -61 36 -61 74c0 21 3 40 8 59l59 231 c4 15 6 21 6 25c0 12 -11 23 -33 23c-7 0 -19 -1 -26 -3l-3 15l157 26l-84 -326c-2 -9 -3 -16 -3 -24c0 -21 8 -34 26 -34c25 0 65 31 100 77c43 57 89 146 109 219l21 75h77Z" id="E1-STIXWEBNORMALI-1D462-gensym001" stroke -width="1"/> <path d="M444 428l-89 -348c-1 -4 -1 -6 -1 -9c0 -8 4 -14 14 -14 c21 0 40 26 57 46l5 6l13 -11c-23 -33 -74 -107 -132 -107c-29 0 -40 19 -40 52c0 9 1 25 4 37l26 95h-1c-7 -5 -97 -126 -137 -156c-23 -17 -49 -28 -72 -28c-47 0 -61 36 -61 74c0 21 3 40 8 59l59 231 c4 15 6 21 6 25c0 12 -11 23 -33 23c-7 0 -19 -1 -26 -3l-3 15l157 26l-84 -326c-2 -9 -3 -16 -3 -24c0 -21 8 -34 26 -34c25 0 65 31 100 77c43 57 89 146 109 219l21 75h77Z" id="E1-STIXWEBNORMALI-1D462-gensym001" stroke -width="1"/>
<path d="M363 111l12 -13c-51 -60 -113 -109 -198 -109c-97 0 -13 7 78 -137 155c0 140 121 297 263 297c50 0 97 -27 97 -76c0 -38 -16 -70 -54 -70c-26 0 -38 21 -38 38c0 24 29 36 29 58c0 12 -10 21 -34 21c-119 0 -176 -179 -176 -259c 0 -87 49 -109 94 -109 c61 0 107 33 142 67Z" id="E1-STIXWEBNORMALI-1D450-gensym00 1" stroke-width="1"/> <path d="M363 111l12 -13c-51 -60 -113 -109 -198 -109c-97 0 -13 7 78 -137 155c0 140 121 297 263 297c50 0 97 -27 97 -76c0 -38 -16 -70 -54 -70c-26 0 -38 21 -38 38c0 24 29 36 29 58c0 12 -10 21 -34 21c-119 0 -176 -179 -176 -259c 0 -87 49 -109 94 -109 c61 0 107 33 142 67Z" id="E1-STIXWEBNORMALI-1D450-gensym00 1" stroke-width="1"/>
<path d="M637 320h-589v66h589v-66zM637 120h-589v66h589v-66Z" i d="E1-STIXWEBMAIN-3D-gensym001" stroke-width="1"/> <path d="M637 320h-589v66h589v-66zM637 120h-589v66h589v-66Z" i d="E1-STIXWEBMAIN-3D-gensym001" stroke-width="1"/>
skipping to change at line 461 skipping to change at line 469
]]></artwork> ]]></artwork>
</artset> </artset>
</figure> </figure>
<aside> <aside>
<t>Editor's note: <t>Editor's note:
This initial set of timescales was deliberately chosen to be frugal, as This initial set of timescales was deliberately chosen to be frugal, as
the specification of the tag provides an extension point where the specification of the tag provides an extension point where
additional timescales can be registered at any time. additional timescales can be registered at any time.
Registrations are clearly needed for earth-referenced timescales (such Registrations are clearly needed for earth-referenced timescales (such
as UT1 and TT), as well as possibly for specific realizations of as UT1 and TT), as well as possibly for specific realizations of
abstract time scales (such as TAI(USNO) which is more accurate as a abstract timescales (such as TAI(USNO), the specific realization obtained at the United States Naval Observatory, which is more accurate as a
constant offset basis for GPS times). constant offset basis for GPS times).
While the registration process itself is trivial, these registrations While the registration process itself is trivial, these registrations
need to be made based on a solid specification of their actual need to be made based on a solid specification of their actual
definition.</t> definition.</t>
</aside> </aside>
</section> </section>
<section anchor="clock-quality"> <section anchor="clock-quality">
<name>Clock Quality</name> <name>Clock Quality</name>
<t>A number of keys are defined to indicate the quality of clock that wa s <t>A number of keys are defined to indicate the quality of clock that wa s
used to determine the point in time.</t> used to determine the point in time.</t>
skipping to change at line 487 skipping to change at line 495
? &(ClockClass: -2) => uint .size 1 ; PTP/RFC8575 ? &(ClockClass: -2) => uint .size 1 ; PTP/RFC8575
? &(ClockAccuracy: -4) => uint .size 1 ; PTP/RFC8575 ? &(ClockAccuracy: -4) => uint .size 1 ; PTP/RFC8575
? &(OffsetScaledLogVariance: -5) => uint .size 2 ; PTP/RFC8575 ? &(OffsetScaledLogVariance: -5) => uint .size 2 ; PTP/RFC8575
? &(Uncertainty: -7) => ~time/~duration ? &(Uncertainty: -7) => ~time/~duration
? &(Guarantee: -8) => ~time/~duration ? &(Guarantee: -8) => ~time/~duration
) )
]]></sourcecode> ]]></sourcecode>
<section anchor="clockclass-key-2"> <section anchor="clockclass-key-2">
<name>ClockClass (Key -2)</name> <name>ClockClass (Key -2)</name>
<t>Key -2 (ClockClass) can be used to indicate the clock class as per <t>Key -2 (ClockClass) can be used to indicate the clock class as per
<xref target="RFC8575"/> (which is based on Table 5 in Section 7.6.2.4 of <xref target="RFC8575"/> (which is based on Table 5 in Section 7.6.2.4 of <xref
<xref target="IEEE1588-2008"/>; Table 4 in Section 7.6.2.5 of <xref target="IEEE target="IEEE1588-2008"/>; Table 4 in Section 7.6.2.5 of <xref target="IEEE1588-2
1588-2019"/> has updated language). 019"/> has updated language).
It is defined as a one-byte unsigned integer as that is the range It is defined as a one-byte unsigned integer as that is the range
defined in IEEE 1588.</t> defined in IEEE 1588.</t>
</section> </section>
<section anchor="clockaccuracy-key-4"> <section anchor="clockaccuracy-key-4">
<name>ClockAccuracy (Key -4)</name> <name>ClockAccuracy (Key -4)</name>
<t>Key -4 (ClockAccuracy) can be used to indicate the clock accuracy a s <t>Key -4 (ClockAccuracy) can be used to indicate the clock accuracy a s
per <xref target="RFC8575"/> (which is based on Table 6 in Section 7.6.2.5 of per <xref target="RFC8575"/> (which is based on Table 6 in Section 7.6.2.5 of <x
<xref target="IEEE1588-2008"/>; additional values have been defined in Table 5 i ref target="IEEE1588-2008"/>; additional values have been defined in Table 5 in
n
Section 7.6.2.6 of <xref target="IEEE1588-2019"/>). Section 7.6.2.6 of <xref target="IEEE1588-2019"/>).
It is defined as a one-byte unsigned integer as that is the range defined there. It is defined as a one-byte unsigned integer as that is the range defined there.
The range between 23 and 47 is a slightly distorted logarithmic scale The range between 23 and 47 is a slightly distorted logarithmic scale
from 1 ps to 1 s in <xref target="IEEE1588-2019"/> (in <xref target="IEEE1588-20 from 1 ps to 1 s in <xref target="IEEE1588-2019"/> (in <xref target="IEEE1588-20
08"/> the range was 08"/>, the range was
a subset of that, 32 to 47 for 25 ns to 1 s) — see a subset of that, 32 to 47 for 25 ns to 1 s) -- see
<xref target="formula-accuracy-enum"/>; the number 254 is the <xref target="formula-accuracy-enum"/>; the number 254 is the
value to be used if an unknown accuracy needs to be expressed.</t> value to be used if an unknown accuracy needs to be expressed.</t>
<!-- Note that the double space after the \approx is actually needed - -> <!-- Note that the double space after the \approx is actually needed - ->
<!-- by utftex --> <!-- by utftex -->
<figure anchor="formula-accuracy-enum"> <figure anchor="formula-accuracy-enum">
<name>Approximate conversion from accuracy to accuracy enumeration v alue</name> <name>Approximate Conversion from Accuracy to Accuracy Enumeration V alue</name>
<artset> <artset>
<artwork type="svg"><svg xmlns:xlink="http://www.w3.org/1999/xlink " xmlns="http://www.w3.org/2000/svg" height="4.676ex" role="img" viewBox="0 -122 1.9 14098.6 2013.3" width="32.745ex"> <artwork type="svg"><svg xmlns:xlink="http://www.w3.org/1999/xlink " xmlns="http://www.w3.org/2000/svg" height="4.676ex" role="img" viewBox="0 -122 1.9 14098.6 2013.3" width="32.745ex">
<defs> <defs>
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<path d="M444 428l-89 -348c-1 -4 -1 -6 -1 -9c0 -8 4 -14 14 - 14c21 0 40 26 57 46l5 6l13 -11c-23 -33 -74 -107 -132 -107c-29 0 -40 19 -40 52c0 9 1 25 4 37l26 95h-1c-7 -5 -97 -126 -137 -156c-23 -17 -49 -28 -72 -28c-47 0 -61 36 -61 74c0 21 3 40 8 59l59 231 c4 15 6 21 6 25c0 12 -11 23 -33 23c-7 0 -19 -1 - 26 -3l-3 15l157 26l-84 -326c-2 -9 -3 -16 -3 -24c0 -21 8 -34 26 -34c25 0 65 31 10 0 77c43 57 89 146 109 219l21 75h77Z" id="E1-STIXWEBNORMALI-1D462-gensym002" stro ke-width="1"/> <path d="M444 428l-89 -348c-1 -4 -1 -6 -1 -9c0 -8 4 -14 14 - 14c21 0 40 26 57 46l5 6l13 -11c-23 -33 -74 -107 -132 -107c-29 0 -40 19 -40 52c0 9 1 25 4 37l26 95h-1c-7 -5 -97 -126 -137 -156c-23 -17 -49 -28 -72 -28c-47 0 -61 36 -61 74c0 21 3 40 8 59l59 231 c4 15 6 21 6 25c0 12 -11 23 -33 23c-7 0 -19 -1 - 26 -3l-3 15l157 26l-84 -326c-2 -9 -3 -16 -3 -24c0 -21 8 -34 26 -34c25 0 65 31 10 0 77c43 57 89 146 109 219l21 75h77Z" id="E1-STIXWEBNORMALI-1D462-gensym002" stro ke-width="1"/>
<path d="M667 107l13 -11c-32 -54 -84 -104 -131 -104c-22 0 -3 9 10 -39 49c0 7 1 17 6 37l56 221c4 14 6 23 6 40c0 20 -6 38 -24 38c-54 0 -164 -18 1 -179 -242l-34 -135h-79l77 299c2 9 5 25 5 40c0 20 -5 38 -23 38c-52 0 -162 -181 -178 -242l-35 -135h-78l95 374 c0 18 -6 31 -33 31c-8 0 -19 -1 -27 -2l-2 14l157 24 l-44 -169h6c94 143 154 169 192 169c37 0 55 -37 55 -81c0 -17 -3 -32 -9 -52l-10 -3 6h5c29 52 81 114 130 147c22 15 41 22 61 22c36 0 54 -26 54 -71c0 -18 -1 -37 -7 -6 1l-61 -231c-1 -3 -2 -9 -2 -12 c0 -8 6 -12 15 -12c17 0 43 16 62 53Z" id="E1-STIXW EBNORMALI-1D45A-gensym002" stroke-width="1"/> <path d="M667 107l13 -11c-32 -54 -84 -104 -131 -104c-22 0 -3 9 10 -39 49c0 7 1 17 6 37l56 221c4 14 6 23 6 40c0 20 -6 38 -24 38c-54 0 -164 -18 1 -179 -242l-34 -135h-79l77 299c2 9 5 25 5 40c0 20 -5 38 -23 38c-52 0 -162 -181 -178 -242l-35 -135h-78l95 374 c0 18 -6 31 -33 31c-8 0 -19 -1 -27 -2l-2 14l157 24 l-44 -169h6c94 143 154 169 192 169c37 0 55 -37 55 -81c0 -17 -3 -32 -9 -52l-10 -3 6h5c29 52 81 114 130 147c22 15 41 22 61 22c36 0 54 -26 54 -71c0 -18 -1 -37 -7 -6 1l-61 -231c-1 -3 -2 -9 -2 -12 c0 -8 6 -12 15 -12c17 0 43 16 62 53Z" id="E1-STIXW EBNORMALI-1D45A-gensym002" stroke-width="1"/>
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<path d="M363 111l12 -13c-51 -60 -113 -109 -198 -109c-97 0 - 137 78 -137 155c0 140 121 297 263 297c50 0 97 -27 97 -76c0 -38 -16 -70 -54 -70c- 26 0 -38 21 -38 38c0 24 29 36 29 58c0 12 -10 21 -34 21c-119 0 -176 -179 -176 -25 9c0 -87 49 -109 94 -109 c61 0 107 33 142 67Z" id="E1-STIXWEBNORMALI-1D450-gensym 002" stroke-width="1"/> <path d="M363 111l12 -13c-51 -60 -113 -109 -198 -109c-97 0 - 137 78 -137 155c0 140 121 297 263 297c50 0 97 -27 97 -76c0 -38 -16 -70 -54 -70c- 26 0 -38 21 -38 38c0 24 29 36 29 58c0 12 -10 21 -34 21c-119 0 -176 -179 -176 -25 9c0 -87 49 -109 94 -109 c61 0 107 33 142 67Z" id="E1-STIXWEBNORMALI-1D450-gensym 002" stroke-width="1"/>
<path d="M604 475h33c-6 -85 -60 -204 -158 -204c-96 0 -203 12 8 -275 128c-70 0 -107 -67 -123 -138h-33c5 100 65 204 163 204c96 0 203 -128 276 - 128c69 0 102 67 117 138zM604 239h33c-6 -85 -60 -204 -158 -204c-96 0 -203 128 -27 5 128c-70 0 -107 -67 -123 -138h-33 c5 100 65 204 163 204c96 0 203 -128 276 -128c 69 0 102 67 117 138Z" id="E1-STIXWEBMAIN-2248-gensym002" stroke-width="1"/> <path d="M604 475h33c-6 -85 -60 -204 -158 -204c-96 0 -203 12 8 -275 128c-70 0 -107 -67 -123 -138h-33c5 100 65 204 163 204c96 0 203 -128 276 - 128c69 0 102 67 117 138zM604 239h33c-6 -85 -60 -204 -158 -204c-96 0 -203 128 -27 5 128c-70 0 -107 -67 -123 -138h-33 c5 100 65 204 163 204c96 0 203 -128 276 -128c 69 0 102 67 117 138Z" id="E1-STIXWEBMAIN-2248-gensym002" stroke-width="1"/>
skipping to change at line 599 skipping to change at line 605
<section anchor="offsetscaledlogvariance-key-5"> <section anchor="offsetscaledlogvariance-key-5">
<name>OffsetScaledLogVariance (Key -5)</name> <name>OffsetScaledLogVariance (Key -5)</name>
<t>Key -5 (OffsetScaledLogVariance) can be used to represent the varia nce <t>Key -5 (OffsetScaledLogVariance) can be used to represent the varia nce
exhibited by the clock when it has lost its synchronization with an exhibited by the clock when it has lost its synchronization with an
external reference clock. The details for the computation of this external reference clock. The details for the computation of this
characteristic are defined in Section 7.6.3 of <xref target="IEEE1588-2019"/> an d the characteristic are defined in Section 7.6.3 of <xref target="IEEE1588-2019"/> an d the
same section in <xref target="IEEE1588-2008"/>.</t> same section in <xref target="IEEE1588-2008"/>.</t>
</section> </section>
<section anchor="uncertainty-key-7"> <section anchor="uncertainty-key-7">
<name>Uncertainty (Key -7)</name> <name>Uncertainty (Key -7)</name>
<t>Key -7 (Uncertainty) can be used to represent a known measurement
uncertainty for the clock, as a numeric value in seconds or as a <t>Key -7 (Uncertainty) can be used to represent a known uncertainty o
duration (<xref target="duration"/>).</t> f measurement for the clock as a numeric value in seconds or as a
<t>For this document, uncertainty is defined as in Section 2.2.3 of duration (<xref target="duration"/>).</t>
<xref target="GUM"/>: "parameter, associated with the result of a measurement, t <t>For this document, uncertainty is defined as in Section 2.2.3 of <x
hat ref target="GUM"/>: "parameter, associated with the result of a measurement, tha
t
characterizes the dispersion of the values that could reasonably be characterizes the dispersion of the values that could reasonably be
attributed to the measurand". More specifically, the value for this attributed to the measurand". More specifically, the value for this
key represents the expanded uncertainty for k = 2 (Section 6.2.1 of <xref target ="GUM"/>), in seconds.</t> key represents the expanded uncertainty for k = 2 (Section 6.2.1 of <xref target ="GUM"/>) in seconds.</t>
<t>Note that the additional information that can be meaningfully provi ded <t>Note that the additional information that can be meaningfully provi ded
with the duration that represents an uncertainty is limited, e.g., it with the duration that represents an uncertainty is limited, e.g., it
is not customary to provide an uncertainty for a duration representing is not customary to provide an uncertainty for a duration representing
an uncertainty. an uncertainty.
Implementations are free to reduce the information contained in an Implementations are free to reduce the information contained in an
uncertainty (which is already elective) to the information they can uncertainty (which is already elective) to the information they can
process.</t> process.</t>
<t>For example, a timestamp that is given to a resolution of <t>For example, a timestamp that is given to a resolution of
10<sup>-6</sup> seconds (microseconds) but only has an uncertainty of 10<sup>-6</sup> seconds (microseconds) but only has an uncertainty of
10<sup>-3</sup> seconds (milliseconds) could be expressed by one of 10<sup>-3</sup> seconds (milliseconds) could be expressed by one of
skipping to change at line 632 skipping to change at line 637
<sourcecode type="cbor-diag"><![CDATA[ <sourcecode type="cbor-diag"><![CDATA[
1001({1: 1697724754, -6: 873294, -7: {1: 0, -6: 1000}}), 1001({1: 1697724754, -6: 873294, -7: {1: 0, -6: 1000}}),
1001({1: 1697724754, -6: 873294, -7: {1: 0, -3: 1}}), 1001({1: 1697724754, -6: 873294, -7: {1: 0, -3: 1}}),
1001({1: 1697724754, -6: 873294, -7: {1: 0.001}}) 1001({1: 1697724754, -6: 873294, -7: {1: 0.001}})
]]></sourcecode> ]]></sourcecode>
</figure> </figure>
</section> </section>
<section anchor="guarantee-key-8"> <section anchor="guarantee-key-8">
<name>Guarantee (Key -8)</name> <name>Guarantee (Key -8)</name>
<t>Key -8 (Guarantee) can be used to represent a stated guarantee for the <t>Key -8 (Guarantee) can be used to represent a stated guarantee for the
accuracy of the point in time, as a numeric value in seconds or as a accuracy of the point in time as a numeric value in seconds or as a
duration (<xref target="duration"/>) duration (<xref target="duration"/>)
representing the maximum allowed deviation from the true value.</t> representing the maximum allowed deviation from the true value.</t>
<t>While such a guarantee is unattainable in theory, existing standard s <t>While such a guarantee is unattainable in theory, existing standard s
such as <xref target="RFC3161"/> stipulate the representation of such guarantees , such as <xref target="RFC3161"/> stipulate the representation of such guarantees ,
and therefore this format provides a way to represent them as well; and therefore this format provides a way to represent them as well;
the time value given is nominally guaranteed to not deviate from the the time value given is nominally guaranteed to not deviate from the
actual time by more than the value of the guarantee, in seconds.</t> actual time by more than the value of the guarantee in seconds.</t>
<t>Note that the additional information that can be meaningfully provi ded <t>Note that the additional information that can be meaningfully provi ded
with the duration that represents a guarantee is limited, e.g., it is with the duration that represents a guarantee is limited, e.g., it is
not meaningful to provide a guarantee of accuracy for the duration not meaningful to provide a guarantee of accuracy for the duration
representing a guarantee of accuracy. representing a guarantee of accuracy.
Implementations are free to reduce a guarantee (which is already Implementations are free to reduce a guarantee (which is already
elective) to the information they can process.</t> elective) to the information they can process.</t>
</section> </section>
</section> </section>
<section anchor="tzh"> <section anchor="tzh">
<name>Keys -10, 10: Time Zone Hint</name> <name>Keys -10, 10: Time Zone Hint</name>
<t>Keys -10 and 10 supply supplementary information, where key 10 is cri tical.</t> <t>Keys -10 and 10 supply supplementary information, where key 10 is cri tical.</t>
<t>They can be used to provide a hint about the time zone that <t>They can be used to provide a hint about the time zone that
would best fit for displaying the time given to humans, using a text would best fit for displaying the time given to humans, using a text
string in the format defined for <tt>time-zone-name</tt> or <tt>time-numoffset</ tt> string in the format defined for <tt>time-zone-name</tt> or <tt>time-numoffset</ tt>
in <xref target="IXDTF"/>. in <xref target="RFC9557"/>.
Key -10 is equivalent to providing this information as an elective Key -10 is equivalent to providing this information as an elective
hint, while key 10 provides this information as critical (i.e., it hint, while key 10 provides this information as critical (i.e., it
<bcp14>MUST</bcp14> be used when interpreting the entry with this key).</t> <bcp14>MUST</bcp14> be used when interpreting the entry with this key).</t>
<t>Keys -10 and 10 <bcp14>MUST NOT</bcp14> both be present.</t> <t>Keys -10 and 10 <bcp14>MUST NOT</bcp14> both be present.</t>
<sourcecode type="cddl"><![CDATA[ <sourcecode type="cddl"><![CDATA[
$$ETIME-ELECTIVE //= (-10: time-zone-info) $$ETIME-ELECTIVE //= (-10: time-zone-info)
$$ETIME-CRITICAL //= (10: time-zone-info) $$ETIME-CRITICAL //= (10: time-zone-info)
time-zone-info = tstr .abnf time-zone-info = tstr .abnf
("time-zone-name / time-numoffset" .det IXDTFtz) ("time-zone-name / time-numoffset" .det IXDTFtz)
IXDTFtz = ' IXDTFtz = '
time-hour = 2DIGIT ; 00-23 time-hour = 2DIGIT ; 00-23
time-minute = 2DIGIT ; 00-59 time-minute = 2DIGIT ; 00-59
time-numoffset = ("+" / "-") time-hour ":" time-minute time-numoffset = ("+" / "-") time-hour ":" time-minute
time-zone-initial = ALPHA / "." / "_" time-zone-initial = ALPHA / "." / "_"
time-zone-char = time-zone-initial / DIGIT / "-" / "+" time-zone-char = time-zone-initial / DIGIT / "-" / "+"
time-zone-part = time-zone-initial *13(time-zone-char) time-zone-part = time-zone-initial *time-zone-char
; but not "." or ".." ; but not "." or ".."
time-zone-name = time-zone-part *("/" time-zone-part) time-zone-name = time-zone-part *("/" time-zone-part)
ALPHA = %x41-5A / %x61-7A ; A-Z / a-z ALPHA = %x41-5A / %x61-7A ; A-Z / a-z
DIGIT = %x30-39 ; 0-9 DIGIT = %x30-39 ; 0-9
' ; extracted from [IXDTF] and [RFC3339]; update as needed ' ; extracted from [RFC9557] and [RFC3339]
]]></sourcecode> ]]></sourcecode>
</section> </section>
<section anchor="suff"> <section anchor="suff">
<name>Keys -11, 11: IXDTF Suffix Information</name> <name>Keys -11, 11: IXDTF Suffix Information</name>
<t>Keys -11 and 11 supply supplementary information, where key 11 is cri tical.</t> <t>Keys -11 and 11 supply supplementary information, where key 11 is cri tical.</t>
<t>Similar to keys -10 and 10, keys -11 (elective) and 11 (critical) can <t>Similar to keys -10 and 10, keys -11 (elective) and 11 (critical) can
be used to provide additional information in the style of IXDTF be used to provide additional information in the style of Internet Extended Date /Time Format (IXDTF)
suffixes, such as the calendar that would best fit for displaying the suffixes, such as the calendar that would best fit for displaying the
time given to humans. time given to humans.
The key's value is a map that has IXDTF <tt>suffix-key</tt> names as keys and The key's value is a map that has IXDTF <tt>suffix-key</tt> names as keys and
corresponding suffix values as values, specifically:</t> corresponding suffix values as values, specifically:</t>
<sourcecode type="cddl"><![CDATA[ <sourcecode type="cddl"><![CDATA[
$$ETIME-ELECTIVE //= (-11: suffix-info-map) $$ETIME-ELECTIVE //= (-11: suffix-info-map)
$$ETIME-CRITICAL //= (11: suffix-info-map) $$ETIME-CRITICAL //= (11: suffix-info-map)
suffix-info-map = { * suffix-key => suffix-values } suffix-info-map = { * suffix-key => suffix-values }
suffix-key = tstr .abnf ("suffix-key" .det IXDTF) suffix-key = tstr .abnf ("suffix-key" .det IXDTF)
suffix-values = one-or-more<suffix-value> suffix-values = one-or-more<suffix-value>
one-or-more<T> = T / [ 2* T ] one-or-more<T> = T / [ 2* T ]
suffix-value = tstr .abnf ("suffix-value" .det IXDTF) suffix-value = tstr .abnf ("suffix-value" .det IXDTF)
IXDTF = ' IXDTF = '
key-initial = lcalpha / "_" key-initial = lcalpha / "_"
key-char = key-initial / DIGIT / "-" key-char = key-initial / DIGIT / "-"
suffix-key = key-initial *key-char suffix-key = key-initial *key-char
suffix-value = 1*alphanum suffix-value = 1*alphanum
alphanum = ALPHA / DIGIT alphanum = ALPHA / DIGIT
lcalpha = %x61-7A lcalpha = %x61-7A
ALPHA = %x41-5A / %x61-7A ; A-Z / a-z ALPHA = %x41-5A / %x61-7A ; A-Z / a-z
DIGIT = %x30-39 ; 0-9 DIGIT = %x30-39 ; 0-9
' ; extracted from [IXDTF]; update as needed! ' ; extracted from [RFC9557]
]]></sourcecode> ]]></sourcecode>
<t>When keys -11 and 11 both are present, the two maps <bcp14>MUST NOT</ bcp14> have <t>When keys -11 and 11 are both present, the two maps <bcp14>MUST NOT</ bcp14> have
entries with the same map keys.</t> entries with the same map keys.</t>
<t>Figure 4 of <xref target="IXDTF"/> gives an example for an extended d <t>Figure 4 of <xref target="RFC9557"/> gives an example for an extended
ate-time with both time zone date-time with both time zone
and suffix information:</t> and suffix information:</t>
<artwork><![CDATA[ <artwork><![CDATA[
1996-12-19T16:39:57-08:00[America/Los_Angeles][u-ca=hebrew] 1996-12-19T16:39:57-08:00[America/Los_Angeles][u-ca=hebrew]
]]></artwork> ]]></artwork>
<t>A time tag that is approximating this example, in CBOR diagnostic <t>A time tag that is approximating this example, in CBOR diagnostic
notation, would be:</t> notation, would be:</t>
<sourcecode type="cbor-diag"><![CDATA[ <sourcecode type="cbor-diag"><![CDATA[
/ 1996-12-19T16:39:57-08:00[America//Los_Angeles][u-ca=hebrew] / / 1996-12-19T16:39:57-08:00[America//Los_Angeles][u-ca=hebrew] /
1001({ 1: 851042397, 1001({ 1: 851042397,
-10: "America/Los_Angeles", -10: "America/Los_Angeles",
-11: { "u-ca": "hebrew" } -11: { "u-ca": "hebrew" }
}) })
]]></sourcecode> ]]></sourcecode>
<t>Note that both -10 and -11 are using negative keys and therefore <t>Note that both -10 and -11 are using negative keys and therefore
provide elective information, as in the IXDTF form given in the comment. provide elective information, as in the IXDTF form given in the comment.
Note also that in this example the time numeric offset (<tt>-08:00</tt>) is Also note that, in this example, the time numeric offset (<tt>-08:00</tt>) is
lost in translating from the <xref target="RFC3339"/> information in the IXDTF i nto a lost in translating from the <xref target="RFC3339"/> information in the IXDTF i nto a
POSIX time that can be included under Key 1 in a time tag.</t> POSIX time that can be included under key 1 in a time tag.</t>
</section> </section>
</section> </section>
<section anchor="duration"> <section anchor="duration">
<name>Duration Format</name> <name>Duration Format</name>
<t>A duration is the length of an interval of time. <t>A duration is the length of an interval of time.
Durations in this format are given in SI seconds, possibly adjusted Durations in this format are given in International System of Units (SI) seconds , possibly adjusted
for conventional corrections of the timescale given (e.g., leap for conventional corrections of the timescale given (e.g., leap
seconds).</t> seconds).</t>
<t>Except for using Tag 1002 instead of 1001, <t>Except for using tag 1002 instead of 1001,
durations are structurally identical to time values.</t> durations are structurally identical to time values.</t>
<sourcecode type="cddl"><![CDATA[ <sourcecode type="cddl"><![CDATA[
Duration = #6.1002(etime-detailed) Duration = #6.1002(etime-detailed)
]]></sourcecode> ]]></sourcecode>
<t>Semantically, they do not measure the time elapsed from a given epoch, <t>Semantically, they do not measure the time elapsed from a given epoch
but from the start to the end of (an otherwise unspecified) interval but from the start to the end of an (otherwise unspecified) interval
of time.</t> of time.</t>
<t>In combination with an epoch identified in the context, a duration can <t>In combination with an epoch identified in the context, a duration can
also be used to express an absolute time.</t> also be used to express an absolute time.</t>
<t>Without such context, durations are subject to some uncertainties <t>Without such context, durations are subject to some uncertainties
underlying the timescale used. underlying the timescale used.
E.g., for durations intended as a determinant of future time periods, For example, for durations intended as a determinant of future time periods,
there is some uncertainty of what irregularities (such as leap there is some uncertainty of what irregularities (such as leap
seconds, timescale corrections) will be exhibited by the timescale in seconds and timescale corrections) will be exhibited by the timescale in
that period. that period.
For durations as measurements of past periods, abstracting the period For durations as measurements of past periods, abstracting the period
to a duration loses some detail about timescale irregularities. to a duration loses some detail about timescale irregularities.
For many applications, these uncertainties are acceptable and thus For many applications, these uncertainties are acceptable and thus
the use of durations is appropriate.</t> the use of durations is appropriate.</t>
<aside> <aside>
<t>Note that the durations defined in <xref target="ISO8601"/> and <xref target="ISO8601-2019"/> are rather different from the ones defined <t>Note that the durations defined in <xref target="ISO8601"/> and <xref target="ISO8601-2019"/> are rather different from the ones defined
in the present specification; there is no intention to support ISO 8601 in the present specification; there is no intention to support ISO 8601
durations here.</t> durations here.</t>
</aside> </aside>
</section> </section>
<section anchor="period"> <section anchor="period">
<name>Period Format</name> <name>Period Format</name>
<t>A period is a specific interval of time, specified as either two <t>A period is a specific interval of time, specified as either two
extended times giving the start and the end of that interval, or as extended times giving the start and the end of that interval or as
one of these two plus a duration.</t> one of these two plus a duration.</t>
<t>This is represented as an array of unwrapped time and duration elements , <t>This is represented as an array of unwrapped time and duration elements ,
tagged with Tag 1003, one of:</t> tagged with tag 1003, one of:</t>
<ul spacing="normal"> <ul spacing="normal">
<li> <li>
<t>a start and end time, in which case the <t>a start and end time, in which case the
tag content is an array of two unwrapped extended time elements;</t> tag content is an array of two unwrapped extended time elements, or</t>
</li> </li>
<li> <li>
<t>a start time with duration or an end time with duration. <t>a start time with duration or an end time with duration.
The tag content is an array of 3 elements: the first two as The tag content is an array of 3 elements: the first two as
above but either the start or end time <bcp14>MUST</bcp14> be set to null; the above but either the start or end time <bcp14>MUST</bcp14> be set to null and th e
third one then is an unwrapped duration.</t> third one then is an unwrapped duration.</t>
</li> </li>
</ul> </ul>
<t>A simple CDDL definition that does not capture all the constraints is:< /t> <t>A simple CDDL definition that does not capture all the constraints is:< /t>
<sourcecode type="cddl"><![CDATA[ <sourcecode type="cddl"><![CDATA[
simple-Period = #6.1003([ simple-Period = #6.1003([
start: ~Etime / null start: ~Etime / null
end: ~Etime / null end: ~Etime / null
? duration: ~Duration ? duration: ~Duration
]) ])
skipping to change at line 808 skipping to change at line 815
((end: ~Etime) // ((end: ~Etime) //
(end: null, (end: null,
duration: ~Duration))) // duration: ~Duration))) //
(start: null, (start: null,
end: ~Etime, end: ~Etime,
duration: ~Duration) duration: ~Duration)
]) ])
]]></sourcecode> ]]></sourcecode>
</section> </section>
<section anchor="cddl-typenames"> <section anchor="cddl-typenames">
<name>CDDL typenames</name> <name>CDDL Type Names</name>
<t>When detailed validation is not needed, the <t>When detailed validation is not needed, the
type names defined in <xref target="tag-cddl"/> are recommended:</t> type names defined in <xref target="tag-cddl"/> are recommended:</t>
<figure anchor="tag-cddl"> <figure anchor="tag-cddl">
<name>Recommended type names for CDDL</name> <name>Recommended Type Names for CDDL</name>
<sourcecode type="cddl"><![CDATA[ <sourcecode type="cddl"><![CDATA[
etime = #6.1001({* (int/tstr) => any}) etime = #6.1001({* (int/tstr) => any})
duration = #6.1002({* (int/tstr) => any}) duration = #6.1002({* (int/tstr) => any})
period = #6.1003([~etime/null, ~etime/null, ~duration/null]) period = #6.1003([~etime/null, ~etime/null, ?~duration])
]]></sourcecode> ]]></sourcecode>
</figure> </figure>
</section> </section>
<section anchor="iana-considerations"> <section anchor="iana-considerations">
<name>IANA Considerations</name> <name>IANA Considerations</name>
<t><cref anchor="to-be-removed">RFC Editor: please replace RFCthis with th
e RFC
number of this RFC, and remove this note.</cref></t>
<section anchor="cbor-tags"> <section anchor="cbor-tags">
<name>CBOR tags</name> <name>CBOR Tags</name>
<t>In the "CBOR Tags" registry <xref target="IANA.cbor-tags"/>, <t>In the "CBOR Tags" registry <xref target="IANA.cbor-tags"/>,
IANA has allocated the tags in <xref target="tab-tag-values"/> from what was at IANA has allocated the tags in <xref target="tab-tag-values"/>.</t>
the
time the
FCFS space, with the present document as the specification reference.</t>
<table anchor="tab-tag-values"> <table anchor="tab-tag-values">
<name>Values for Tags</name> <name>Values for Tags</name>
<thead> <thead>
<tr> <tr>
<th align="right">Tag</th> <th align="right">Tag</th>
<th align="left">Data Item</th> <th align="left">Data Item</th>
<th align="left">Semantics</th> <th align="left">Semantics</th>
<th align="left">Reference</th>
</tr> </tr>
</thead> </thead>
<tbody> <tbody>
<tr> <tr>
<td align="right">1001</td> <td align="right">1001</td>
<td align="left">map</td> <td align="left">map</td>
<td align="left">[RFCthis] extended time</td> <td align="left">extended time</td>
<td align="left">[RFC9581, <xref target="time-format"/>]</td>
</tr> </tr>
<tr> <tr>
<td align="right">1002</td> <td align="right">1002</td>
<td align="left">map</td> <td align="left">map</td>
<td align="left">[RFCthis] duration</td> <td align="left">duration</td>
<td align="left">[RFC9581, <xref target="duration"/>]</td>
</tr> </tr>
<tr> <tr>
<td align="right">1003</td> <td align="right">1003</td>
<td align="left">array</td> <td align="left">array</td>
<td align="left">[RFCthis] period</td> <td align="left">period</td>
<td align="left">[RFC9581, <xref target="period"/>]</td>
</tr> </tr>
</tbody> </tbody>
</table> </table>
<t>IANA is requested to change the "Data Item" column for Tag 1003 from <t>IANA has updated the "Data Item" column for tag 1003 from
"map" to "array".</t> "map" to "array".</t>
</section> </section>
<section anchor="timescale-registry"> <section anchor="timescale-registry">
<name>Timescale Registry</name> <name>Timescales Registry</name>
<t>This specification defines a new registry titled "Timescales" in the <t>Per this specification, IANA has created a new "Timescales" registry
"CBOR Tags" registry group <xref target="IANA.cbor-tags"/>, with a Registration within the
Procedure "Concise Binary Object Representation (CBOR) Tags" registry group <xref target="
requiring both "Expert Review" and "RFC Required" (Sections <xref section="4.5" IANA.cbor-tags"/>. The registration procedure requires both
sectionFormat="bare" target="BCP26"/> and <xref section="4.7" sectionFormat="bar "Expert Review" and "RFC Required" (Sections <xref section="4.5" sectionFormat="
e" target="BCP26"/> of <xref target="BCP26"/>).</t> bare" target="RFC8126"/> and
<xref section="4.7" sectionFormat="bare" target="RFC8126"/> of RFC 8126 <xref ta
rget="BCP26"/>, respectively).</t>
<t>Each entry needs to provide a timescale name (a sequence of uppercase <t>Each entry needs to provide a timescale name (a sequence of uppercase
ASCII characters and digits, where a digit may not occur at the start: ASCII characters and digits, where a digit may not occur at the start:
<tt>[A-Z][A-Z0-9]*</tt>), a value (CBOR unsigned integer, uint, <tt>[A-Z][A-Z0-9]*</tt>), a value (CBOR unsigned integer, uint,
0..18446744073709551615), a brief description 0..18446744073709551615), a brief description
of the semantics, and a specification reference (RFC). of the semantics, and a specification reference (RFC).
The initial contents are shown in <xref target="tab-timescales"/>.</t> The initial contents are shown in <xref target="tab-timescales"/>.</t>
<table anchor="tab-timescales"> <table anchor="tab-timescales">
<name>Initial Content of Timescale Registry</name> <name>Initial Content of Timescale Registry</name>
<thead> <thead>
<tr> <tr>
skipping to change at line 886 skipping to change at line 894
<th align="right">Value</th> <th align="right">Value</th>
<th align="left">Semantics</th> <th align="left">Semantics</th>
<th align="left">Reference</th> <th align="left">Reference</th>
</tr> </tr>
</thead> </thead>
<tbody> <tbody>
<tr> <tr>
<td align="left">UTC</td> <td align="left">UTC</td>
<td align="right">0</td> <td align="right">0</td>
<td align="left">UTC with POSIX Epoch</td> <td align="left">UTC with POSIX Epoch</td>
<td align="left">[RFCthis]</td> <td align="left">[RFC9581]</td>
</tr> </tr>
<tr> <tr>
<td align="left">TAI</td> <td align="left">TAI</td>
<td align="right">1</td> <td align="right">1</td>
<td align="left">TAI with PTP Epoch</td> <td align="left">TAI with PTP Epoch</td>
<td align="left">[RFCthis]</td> <td align="left">[RFC9581]</td>
</tr> </tr>
</tbody> </tbody>
</table> </table>
</section> </section>
<section anchor="map-key-registry"> <section anchor="map-key-registry">
<name>Time Tag Map Key Registry</name> <name>Time Tag Map Keys Registry</name>
<t>This specification defines a new registry titled "Time Tag Map Keys" <t>Per this specification, IANA has created a new "Time Tag Map Keys" re
in the "CBOR Tags" registry group <xref target="IANA.cbor-tags"/>, with "Specifi gistry within the "Concise Binary Object Representation (CBOR) Tags" registry gr
cation oup <xref target="IANA.cbor-tags"/>. The registration procedure is "Specificat
Required" as the Registration Procedure (<xref section="4.6" sectionFormat="of" ion
target="BCP26"/>).</t> Required" (Section <xref section="4.6" sectionFormat="bare" target="RFC8126"/> o
f RFC 8126 <xref target="BCP26"/>).</t>
<t>The designated expert is requested to assign the key values with the <t>The designated expert is requested to assign the key values with the
shortest encodings (1+0 and 1+1 encoding) to registrations that are shortest encodings (1+0 and 1+1 encoding) to registrations that are
likely to enjoy wide use and can benefit from short encodings.</t> likely to enjoy wide use and can benefit from short encodings.</t>
<t>Each entry needs to provide a map key value (CBOR integer, int, <t>Each entry needs to provide a map key value (CBOR integer, int,
-18446744073709551616..18446744073709551615), a brief description -18446744073709551616..18446744073709551615), a brief description
of the semantics, and a specification reference. of the semantics, and a specification reference.
Note that negative integers indicate an elective key, while unsigned Note that negative integers indicate an elective key, while unsigned
integers indicate a key that either provides a base time or is integers indicate a key that either provides a base time or is
critical. critical. The designated expert is requested to discuss with the registrant
whether or not it is desirable to register a pair of an elective and a
critical key for the same information, where the elective key value
is the negative of the critical key (similar to how for example -11
and 11 have been assigned in <xref target="tab-mapkeys"/>).
For the unsigned integers as keys, the choice of base time or critical For the unsigned integers as keys, the choice of base time or critical
needs to be indicated in the brief semantics description. needs to be indicated in the brief semantics description.
(Elective map keys may be explicitly marked as such in the (Elective map keys may be explicitly marked as such in the
description, e.g., to distinguish them from critical keys.)</t> description, e.g., to distinguish them from critical keys.)</t>
<t>The initial contents are shown in <xref target="tab-mapkeys"/>.</t> <t>The initial contents are shown in <xref target="tab-mapkeys"/>.</t>
<table anchor="tab-mapkeys"> <table anchor="tab-mapkeys">
<name>Initial Content of Time Tag Map Keys Registry</name> <name>Initial Content of Time Tag Map Keys Registry</name>
<thead> <thead>
<tr> <tr>
<th align="right">Value</th> <th align="right">Value</th>
<th align="left">Semantics</th> <th align="left">Semantics</th>
<th align="left">Reference</th> <th align="left">Reference</th>
</tr> </tr>
</thead> </thead>
<tbody> <tbody>
<tr> <tr>
<td align="right">-18</td> <td align="right">-18</td>
<td align="left">attoseconds</td> <td align="left">attoseconds</td>
<td align="left">[RFCthis]</td> <td align="left">[RFC9581]</td>
</tr> </tr>
<tr> <tr>
<td align="right">-15</td> <td align="right">-15</td>
<td align="left">femtoseconds</td> <td align="left">femtoseconds</td>
<td align="left">[RFCthis]</td> <td align="left">[RFC9581]</td>
</tr> </tr>
<tr>
<td align="right">-13</td>
<td align="left">timescale (elective)</td>
<td align="left">[RFC9581]</td>
</tr>
<tr> <tr>
<td align="right">-12</td> <td align="right">-12</td>
<td align="left">picoseconds</td> <td align="left">picoseconds</td>
<td align="left">[RFCthis]</td> <td align="left">[RFC9581]</td>
</tr> </tr>
<tr> <tr>
<td align="right">-11</td> <td align="right">-11</td>
<td align="left">IXDTF Suffix Information (elective)</td> <td align="left">IXDTF Suffix Information (elective)</td>
<td align="left">[RFCthis], <xref target="IXDTF"/></td> <td align="left">[RFC9581], <xref target="RFC9557"/></td>
</tr> </tr>
<tr> <tr>
<td align="right">-10</td> <td align="right">-10</td>
<td align="left">IXDTF Time Zone Hint (elective)</td> <td align="left">IXDTF Time Zone Hint (elective)</td>
<td align="left">[RFCthis], <xref target="IXDTF"/></td> <td align="left">[RFC9581], <xref target="RFC9557"/></td>
</tr> </tr>
<tr> <tr>
<td align="right">-9</td> <td align="right">-9</td>
<td align="left">nanoseconds</td> <td align="left">nanoseconds</td>
<td align="left">[RFCthis]</td> <td align="left">[RFC9581]</td>
</tr> </tr>
<tr> <tr>
<td align="right">-8</td> <td align="right">-8</td>
<td align="left">Guarantee</td> <td align="left">Guarantee</td>
<td align="left">[RFCthis]</td> <td align="left">[RFC9581]</td>
</tr> </tr>
<tr> <tr>
<td align="right">-7</td> <td align="right">-7</td>
<td align="left">Uncertainty</td> <td align="left">Uncertainty</td>
<td align="left">[RFCthis]</td> <td align="left">[RFC9581]</td>
</tr> </tr>
<tr> <tr>
<td align="right">-6</td> <td align="right">-6</td>
<td align="left">microseconds</td> <td align="left">microseconds</td>
<td align="left">[RFCthis]</td> <td align="left">[RFC9581]</td>
</tr> </tr>
<tr> <tr>
<td align="right">-5</td> <td align="right">-5</td>
<td align="left">Offset-Scaled Log Variance</td> <td align="left">Offset-Scaled Log Variance</td>
<td align="left">[RFCthis]</td> <td align="left">[RFC9581]</td>
</tr> </tr>
<tr> <tr>
<td align="right">-4</td> <td align="right">-4</td>
<td align="left">Clock Accuracy</td> <td align="left">Clock Accuracy</td>
<td align="left">[RFCthis]</td> <td align="left">[RFC9581]</td>
</tr> </tr>
<tr> <tr>
<td align="right">-3</td> <td align="right">-3</td>
<td align="left">milliseconds</td> <td align="left">milliseconds</td>
<td align="left">[RFCthis]</td> <td align="left">[RFC9581]</td>
</tr> </tr>
<tr> <tr>
<td align="right">-2</td> <td align="right">-2</td>
<td align="left">Clock Class</td> <td align="left">Clock Class</td>
<td align="left">[RFCthis]</td> <td align="left">[RFC9581]</td>
</tr> </tr>
<tr>
<td align="right">-1</td>
<td align="left">timescale (elective) legacy</td>
<td align="left">[RFC9581]</td>
</tr>
<tr> <tr>
<td align="right">1</td> <td align="right">1</td>
<td align="left">base time value as in CBOR Tag 1</td> <td align="left">base time value as in CBOR tag 1</td>
<td align="left"> <td align="left">
<xref target="RFC8949"/> [RFCthis]</td> <xref target="RFC8949"/>, [RFC9581]</td>
</tr> </tr>
<tr> <tr>
<td align="right">4</td> <td align="right">4</td>
<td align="left">base time value as in CBOR Tag 4</td> <td align="left">base time value as in CBOR tag 4</td>
<td align="left"> <td align="left">
<xref target="RFC8949"/> [RFCthis]</td> <xref target="RFC8949"/>, [RFC9581]</td>
</tr> </tr>
<tr> <tr>
<td align="right">5</td> <td align="right">5</td>
<td align="left">base time value as in CBOR Tag 5</td> <td align="left">base time value as in CBOR tag 5</td>
<td align="left"> <td align="left">
<xref target="RFC8949"/> [RFCthis]</td> <xref target="RFC8949"/>, [RFC9581]</td>
</tr> </tr>
<tr> <tr>
<td align="right">10</td> <td align="right">10</td>
<td align="left">IXDTF Time Zone Hint (critical)</td> <td align="left">IXDTF Time Zone Hint (critical)</td>
<td align="left">[RFCthis], <xref target="IXDTF"/></td> <td align="left"><xref target="RFC9557"/>, [RFC9581]</td>
</tr> </tr>
<tr> <tr>
<td align="right">11</td> <td align="right">11</td>
<td align="left">IXDTF Suffix Information (critical)</td> <td align="left">IXDTF Suffix Information (critical)</td>
<td align="left">[RFCthis], <xref target="IXDTF"/></td> <td align="left"><xref target="RFC9557"/>, [RFC9581]</td>
</tr> </tr>
<tr>
<td align="right">13</td>
<td align="left">timescale (critical)</td>
<td align="left">[RFC9581]</td>
</tr>
</tbody> </tbody>
</table> </table>
</section> </section>
</section> </section>
<section anchor="security-considerations"> <section anchor="security-considerations">
<name>Security Considerations</name> <name>Security Considerations</name>
<t>The security considerations of <xref target="RFC8949"/> apply; the tags introduced <t>The security considerations of <xref target="RFC8949"/> apply; the tags introduced
here are not expected to raise security considerations beyond those.</t> here are not expected to raise security considerations beyond those.</t>
<t>Time, of course, has significant security considerations; these <t>Time, of course, has significant security considerations; these
include the exploitation of ambiguities where time is security include the exploitation of ambiguities where time is security
relevant (e.g., for freshness or in a validity span) or the disclosure relevant (e.g., for freshness or in a validity span) or the disclosure
of characteristics of the emitting system (e.g., time zone, or clock of characteristics of the emitting system (e.g., time zone or clock
resolution and wall clock offset).</t> resolution and wall clock offset).</t>
<t>A more detailed discussion of security considerations emanating from <t>A more detailed discussion of security considerations emanating from
using a representation of time that allows the inclusion of complex, using a representation of time that allows the inclusion of complex and
possibly inconsistent information is available in possibly inconsistent information is available in "Security Considerations"
Section <xref section="7" sectionFormat="bare" target="IXDTF">Security Considera (<xref section="7" sectionFormat="of" target="RFC9557"></xref>).</t>
tions</xref> of <xref target="IXDTF"/>.</t>
</section> </section>
</middle> </middle>
<back> <back>
<displayreference target="ISO8601" to="ISO8601:1988"/> <displayreference target="ISO8601" to="ISO8601:1988"/>
<displayreference target="ISO8601-2019" to="ISO8601-1:2019"/> <displayreference target="ISO8601-2019" to="ISO8601-1:2019"/>
<references> <references>
<name>References</name> <name>References</name>
<references anchor="sec-normative-references"> <references anchor="sec-normative-references">
<name>Normative References</name> <name>Normative References</name>
<reference anchor="RFC8949">
<front> <xi:include
<title>Concise Binary Object Representation (CBOR)</title> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8949.xml"/
<author fullname="C. Bormann" initials="C." surname="Bormann"/> >
<author fullname="P. Hoffman" initials="P." surname="Hoffman"/>
<date month="December" year="2020"/> <referencegroup anchor="BCP26" target="https://www.rfc-editor.org/info/bc
<abstract> p26">
<t>The Concise Binary Object Representation (CBOR) is a data forma <xi:include
t whose design goals include the possibility of extremely small code size, fairl href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8126.xml"/
y small message size, and extensibility without the need for version negotiation >
. These design goals make it different from earlier binary serializations such a </referencegroup>
s ASN.1 and MessagePack.</t>
<t>This document obsoletes RFC 7049, providing editorial improveme
nts, new details, and errata fixes while keeping full compatibility with the int
erchange format of RFC 7049. It does not create a new version of the format.</t>
</abstract>
</front>
<seriesInfo name="STD" value="94"/>
<seriesInfo name="RFC" value="8949"/>
<seriesInfo name="DOI" value="10.17487/RFC8949"/>
</reference>
<reference anchor="BCP26">
<front>
<title>Guidelines for Writing an IANA Considerations Section in RFCs
</title>
<author fullname="M. Cotton" initials="M." surname="Cotton"/>
<author fullname="B. Leiba" initials="B." surname="Leiba"/>
<author fullname="T. Narten" initials="T." surname="Narten"/>
<date month="June" year="2017"/>
<abstract>
<t>Many protocols make use of points of extensibility that use con
stants to identify various protocol parameters. To ensure that the values in the
se fields do not have conflicting uses and to promote interoperability, their al
locations are often coordinated by a central record keeper. For IETF protocols,
that role is filled by the Internet Assigned Numbers Authority (IANA).</t>
<t>To make assignments in a given registry prudently, guidance des
cribing the conditions under which new values should be assigned, as well as whe
n and how modifications to existing values can be made, is needed. This document
defines a framework for the documentation of these guidelines by specification
authors, in order to assure that the provided guidance for the IANA Consideratio
ns is clear and addresses the various issues that are likely in the operation of
a registry.</t>
<t>This is the third edition of this document; it obsoletes RFC 52
26.</t>
</abstract>
</front>
<seriesInfo name="BCP" value="26"/>
<seriesInfo name="RFC" value="8126"/>
<seriesInfo name="DOI" value="10.17487/RFC8126"/>
</reference>
<reference anchor="TIME_T" target="http://pubs.opengroup.org/onlinepubs/ 9699919799/basedefs/V1_chap04.html#tag_04_16"> <reference anchor="TIME_T" target="http://pubs.opengroup.org/onlinepubs/ 9699919799/basedefs/V1_chap04.html#tag_04_16">
<front> <front>
<title>Vol. 1: Base Definitions, Issue 7</title> <title>The Open Group Base Specifications Issue 7</title>
<author> <author>
<organization>The Open Group Base Specifications</organization> <organization>IEEE</organization>
</author> </author>
<date year="2018"/> <date year="2018"/>
</front> </front>
<seriesInfo name="Section 4.16" value="'Seconds Since the Epoch'"/>
<seriesInfo name="IEEE Std" value="1003.1-2017"/> <seriesInfo name="IEEE Std" value="1003.1-2017"/>
<seriesInfo name="2018" value="Edition"/> <refcontent>Section 4.16 Seconds Since the Epoch</refcontent>
</reference> </reference>
<reference anchor="SI-SECOND">
<reference anchor="SI-SECOND" target="https://www.iso.org/standard/64974
.html">
<front> <front>
<title>Quantities and units — Part 3: Space and time</title> <title>Quantities and units -- Part 3: Space and time</title>
<author> <author>
<organization>International Organization for Standardization (ISO) </organization> <organization>ISO</organization>
</author> </author>
<date day="01" month="March" year="2006"/> <date month="October" year="2019"/>
</front>
<seriesInfo name="ISO" value="80000-3"/>
</reference>
<reference anchor="RFC8575">
<front>
<title>YANG Data Model for the Precision Time Protocol (PTP)</title>
<author fullname="Y. Jiang" initials="Y." role="editor" surname="Jia
ng"/>
<author fullname="X. Liu" initials="X." surname="Liu"/>
<author fullname="J. Xu" initials="J." surname="Xu"/>
<author fullname="R. Cummings" initials="R." role="editor" surname="
Cummings"/>
<date month="May" year="2019"/>
<abstract>
<t>This document defines a YANG data model for the configuration o
f devices and clocks using the Precision Time Protocol (PTP) as specified in IEE
E Std 1588-2008. It also defines the retrieval of the configuration information,
the data sets and the running states of PTP clocks. The YANG module in this doc
ument conforms to the Network Management Datastore Architecture (NMDA).</t>
</abstract>
</front> </front>
<seriesInfo name="RFC" value="8575"/> <seriesInfo name="ISO" value="80000-3:2019"/>
<seriesInfo name="DOI" value="10.17487/RFC8575"/>
</reference> </reference>
<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8575.xml"
/>
<reference anchor="IEEE1588-2008" target="https://standards.ieee.org/iee e/1588/4355/"> <reference anchor="IEEE1588-2008" target="https://standards.ieee.org/iee e/1588/4355/">
<front> <front>
<title>IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems</title> <title>IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems</title>
<author> <author>
<organization>IEEE</organization> <organization>IEEE</organization>
</author> </author>
<date month="July" year="2008"/> <date month="July" year="2008"/>
</front> </front>
<seriesInfo name="IEEE" value="1588-2008"/> <seriesInfo name="IEEE" value="1588-2008"/>
<annotation>Often called PTP v2, as it replaced the earlier 2002 versi on of this standard by a non-backwards compatible protocol.</annotation> <annotation>Often called PTP v2, as it replaced the earlier 2002 versi on of this standard by a non-backwards compatible protocol.</annotation>
skipping to change at line 1136 skipping to change at line 1129
<front> <front>
<title>IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems</title> <title>IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems</title>
<author> <author>
<organization>IEEE</organization> <organization>IEEE</organization>
</author> </author>
<date month="June" year="2020"/> <date month="June" year="2020"/>
</front> </front>
<seriesInfo name="IEEE" value="1588-2019"/> <seriesInfo name="IEEE" value="1588-2019"/>
<annotation>Often called PTP v2.1, as it has been designed so it can b e used in a way that is fully backwards compatible to IEEE1588-2008.</annotation > <annotation>Often called PTP v2.1, as it has been designed so it can b e used in a way that is fully backwards compatible to IEEE1588-2008.</annotation >
</reference> </reference>
<reference anchor="GUM" target="https://www.bipm.org/en/publications/gui des/gum.html"> <reference anchor="GUM" target="https://www.bipm.org/en/publications/gui des/gum.html">
<front> <front>
<title>Evaluation of measurement data — Guide to the expression of u ncertainty in measurement</title> <title>Evaluation of measurement data -- Guide to the expression of uncertainty in measurement</title>
<author> <author>
<organization>Joint Committee for Guides in Metrology</organizatio n> <organization>Joint Committee for Guides in Metrology</organizatio n>
</author> </author>
<date month="September" year="2008"/> <date month="September" year="2008"/>
</front> </front>
<seriesInfo name="JCGM" value="100:2008"/> <seriesInfo name="JCGM" value="100:2008"/>
</reference> </reference>
<reference anchor="IANA.cbor-tags" target="https://www.iana.org/assignme nts/cbor-tags"> <reference anchor="IANA.cbor-tags" target="https://www.iana.org/assignme nts/cbor-tags">
<front> <front>
<title>Concise Binary Object Representation (CBOR) Tags</title> <title>Concise Binary Object Representation (CBOR) Tags</title>
<author> <author>
<organization>IANA</organization> <organization>IANA</organization>
</author> </author>
</front> </front>
</reference> </reference>
<reference anchor="RFC8610">
<front>
<title>Concise Data Definition Language (CDDL): A Notational Convent
ion to Express Concise Binary Object Representation (CBOR) and JSON Data Structu
res</title>
<author fullname="H. Birkholz" initials="H." surname="Birkholz"/>
<author fullname="C. Vigano" initials="C." surname="Vigano"/>
<author fullname="C. Bormann" initials="C." surname="Bormann"/>
<date month="June" year="2019"/>
<abstract>
<t>This document proposes a notational convention to express Conci
se Binary Object Representation (CBOR) data structures (RFC 7049). Its main goal
is to provide an easy and unambiguous way to express structures for protocol me
ssages and data formats that use CBOR or JSON.</t>
</abstract>
</front>
<seriesInfo name="RFC" value="8610"/>
<seriesInfo name="DOI" value="10.17487/RFC8610"/>
</reference>
<reference anchor="IXDTF">
<front>
<title>Date and Time on the Internet: Timestamps with additional inf
ormation</title>
<author fullname="Ujjwal Sharma" initials="U." surname="Sharma">
<organization>Igalia, S.L.</organization>
</author>
<author fullname="Carsten Bormann" initials="C." surname="Bormann">
<organization>Universität Bremen TZI</organization>
</author>
<date day="23" month="October" year="2023"/>
<abstract>
<t> This document defines an extension to the timestamp format d
efined in
RFC3339 for representing additional information including a time
zone.
It updates RFC3339 in the specific interpretation of the local offset <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8610.xml"
Z, which is no longer understood to "imply that UTC is the preferred />
reference point for the specified time"; see Section 2. <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9557.xml"
/>
// (This "cref" paragraph will be removed by the RFC editor:) The <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2119.xml"
// present version (-11) addresses comments received during IESG />
// review. <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8174.xml"
/>
</t>
</abstract>
</front>
<seriesInfo name="Internet-Draft" value="draft-ietf-sedate-datetime-ex
tended-11"/>
</reference>
<reference anchor="RFC2119">
<front>
<title>Key words for use in RFCs to Indicate Requirement Levels</tit
le>
<author fullname="S. Bradner" initials="S." surname="Bradner"/>
<date month="March" year="1997"/>
<abstract>
<t>In many standards track documents several words are used to sig
nify the requirements in the specification. These words are often capitalized. T
his document defines these words as they should be interpreted in IETF documents
. This document specifies an Internet Best Current Practices for the Internet Co
mmunity, and requests discussion and suggestions for improvements.</t>
</abstract>
</front>
<seriesInfo name="BCP" value="14"/>
<seriesInfo name="RFC" value="2119"/>
<seriesInfo name="DOI" value="10.17487/RFC2119"/>
</reference>
<reference anchor="RFC8174">
<front>
<title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</ti
tle>
<author fullname="B. Leiba" initials="B." surname="Leiba"/>
<date month="May" year="2017"/>
<abstract>
<t>RFC 2119 specifies common key words that may be used in protoco
l specifications. This document aims to reduce the ambiguity by clarifying that
only UPPERCASE usage of the key words have the defined special meanings.</t>
</abstract>
</front>
<seriesInfo name="BCP" value="14"/>
<seriesInfo name="RFC" value="8174"/>
<seriesInfo name="DOI" value="10.17487/RFC8174"/>
</reference>
</references> </references>
<references anchor="sec-informative-references">
<references anchor="sec-informative-references">
<name>Informative References</name> <name>Informative References</name>
<reference anchor="RFC3161">
<front> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.3161.xml"
<title>Internet X.509 Public Key Infrastructure Time-Stamp Protocol />
(TSP)</title> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.3339.xml"
<author fullname="C. Adams" initials="C." surname="Adams"/> />
<author fullname="P. Cain" initials="P." surname="Cain"/>
<author fullname="D. Pinkas" initials="D." surname="Pinkas"/>
<author fullname="R. Zuccherato" initials="R." surname="Zuccherato"/
>
<date month="August" year="2001"/>
<abstract>
<t>This document describes the format of a request sent to a Time
Stamping Authority (TSA) and of the response that is returned. It also establish
es several security-relevant requirements for TSA operation, with regards to pro
cessing requests to generate responses. [STANDARDS-TRACK]</t>
</abstract>
</front>
<seriesInfo name="RFC" value="3161"/>
<seriesInfo name="DOI" value="10.17487/RFC3161"/>
</reference>
<reference anchor="RFC3339">
<front>
<title>Date and Time on the Internet: Timestamps</title>
<author fullname="G. Klyne" initials="G." surname="Klyne"/>
<author fullname="C. Newman" initials="C." surname="Newman"/>
<date month="July" year="2002"/>
<abstract>
<t>This document defines a date and time format for use in Interne
t protocols that is a profile of the ISO 8601 standard for representation of dat
es and times using the Gregorian calendar.</t>
</abstract>
</front>
<seriesInfo name="RFC" value="3339"/>
<seriesInfo name="DOI" value="10.17487/RFC3339"/>
</reference>
<reference anchor="ISO8601" target="https://www.iso.org/standard/15903.h tml"> <reference anchor="ISO8601" target="https://www.iso.org/standard/15903.h tml">
<front> <front>
<title>Data elements and interchange formats — Information interchan ge — Representation of dates and times</title> <title>Data elements and interchange formats -- Information intercha nge -- Representation of dates and times</title>
<author> <author>
<organization abbrev="ISO">International Organization for Standard ization</organization> <organization>ISO</organization>
</author> </author>
<date month="June" year="1988"/> <date month="June" year="1988"/>
</front> </front>
<seriesInfo name="ISO" value="8601:1988"/> <seriesInfo name="ISO" value="8601:1988"/>
<annotation>Also available from &lt;⁠<eref target="https://nvlpubs.nis t.gov/nistpubs/Legacy/FIPS/fipspub4-1-1991.pdf">https://nvlpubs.nist.gov/nistpub s/Legacy/FIPS/fipspub4-1-1991.pdf</eref>&gt;.</annotation> <annotation>Also available from &lt;<eref target="https://nvlpubs.nist .gov/nistpubs/Legacy/FIPS/fipspub4-1-1991.pdf">https://nvlpubs.nist.gov/nistpubs /Legacy/FIPS/fipspub4-1-1991.pdf</eref>&gt;.</annotation>
</reference> </reference>
<reference anchor="ISO8601-2019" target="https://www.iso.org/standard/70 907.html"> <reference anchor="ISO8601-2019" target="https://www.iso.org/standard/70 907.html">
<front> <front>
<title>Date and time — Representations for information interchange — Part 1: Basic rules</title> <title>Date and time -- Representations for information interchange -- Part 1: Basic rules</title>
<author> <author>
<organization abbrev="ISO">International Organization for Standard ization</organization> <organization>ISO</organization>
</author> </author>
<date month="February" year="2019"/> <date month="February" year="2019"/>
</front> </front>
<seriesInfo name="ISO" value="8601-1:2019"/> <seriesInfo name="ISO" value="8601-1:2019"/>
</reference> </reference>
<reference anchor="C" target="https://www.iso.org/standard/74528.html"> <reference anchor="C" target="https://www.iso.org/standard/74528.html">
<front> <front>
<title>Information technology — Programming languages — C</title> <title>Information technology -- Programming languages -- C</title>
<author> <author>
<organization>International Organization for Standardization</orga nization> <organization>ISO</organization>
</author> </author>
<date month="June" year="2018"/> <date month="June" year="2018"/>
</front> </front>
<seriesInfo name="ISO/IEC" value="9899:2018"/> <seriesInfo name="ISO/IEC" value="9899:2018"/>
<annotation>Contents available via &lt;⁠<eref target="https://www.open -std.org/jtc1/sc22/wg14/www/docs/n2310.pdf">https://www.open-std.org/jtc1/sc22/w g14/www/docs/n2310.pdf</eref>&gt;</annotation> <annotation>Contents available via &lt;<eref target="https://www.open- std.org/jtc1/sc22/wg14/www/docs/n2310.pdf"/>&gt;</annotation>
<refcontent>Fourth Edition</refcontent> <refcontent>Fourth Edition</refcontent>
</reference> </reference>
<reference anchor="RFC5905">
<front> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5905.xml"
<title>Network Time Protocol Version 4: Protocol and Algorithms Spec />
ification</title>
<author fullname="D. Mills" initials="D." surname="Mills"/> <reference anchor="IEEE754" target="https://ieeexplore.ieee.org/document/8766229
<author fullname="J. Martin" initials="J." role="editor" surname="Ma ">
rtin"/> <front>
<author fullname="J. Burbank" initials="J." surname="Burbank"/> <title>IEEE Standard for Floating-Point Arithmetic</title>
<author fullname="W. Kasch" initials="W." surname="Kasch"/> <author>
<date month="June" year="2010"/> <organization>IEEE</organization>
<abstract> </author>
<t>The Network Time Protocol (NTP) is widely used to synchronize c <date month="July" year="2019"/>
omputer clocks in the Internet. This document describes NTP version 4 (NTPv4), w </front>
hich is backwards compatible with NTP version 3 (NTPv3), described in RFC 1305, <seriesInfo name="IEEE" value="754-2019"/>
as well as previous versions of the protocol. NTPv4 includes a modified protocol <seriesInfo name="DOI" value="10.1109/IEEESTD.2019.8766229"/>
header to accommodate the Internet Protocol version 6 address family. NTPv4 inc </reference>
ludes fundamental improvements in the mitigation and discipline algorithms that
extend the potential accuracy to the tens of microseconds with modern workstatio </references>
ns and fast LANs. It includes a dynamic server discovery scheme, so that in many
cases, specific server configuration is not required. It corrects certain error
s in the NTPv3 design and implementation and includes an optional extension mech
anism. [STANDARDS-TRACK]</t>
</abstract>
</front>
<seriesInfo name="RFC" value="5905"/>
<seriesInfo name="DOI" value="10.17487/RFC5905"/>
</reference>
</references>
</references> </references>
<?line 895?> <?line 895?>
<section anchor="collected-cddl"> <section anchor="collected-cddl">
<name>Collected CDDL</name> <name>Collected CDDL</name>
<t>This appendix collects the CDDL rules spread over the document into <t>This appendix collects the CDDL rules spread over the document into
one convenient place.</t> one convenient place.</t>
<figure anchor="fig-collected-cddl"> <figure anchor="fig-collected-cddl">
<name>Collected CDDL rules from this specification</name> <name>Collected CDDL Rules from This Specification</name>
<sourcecode name="time-tag-collected-cddl.cddl" type="cddl"><![CDATA[ <sourcecode name="time-tag-collected-cddl.cddl" type="cddl"><![CDATA[
Etime = #6.1001(etime-detailed) Etime = #6.1001(etime-detailed)
etime-framework = { etime-framework = {
uint => any ; at least one base time uint => any ; at least one base time
* (nint/text) => any ; elective supplementary information * (nint/text) => any ; elective supplementary information
* uint => any ; critical supplementary information * uint => any ; critical supplementary information
} }
etime-detailed = ({ etime-detailed = ({
skipping to change at line 1342 skipping to change at line 1255
$$ETIME-BASETIME //= (5: ~bigfloat) $$ETIME-BASETIME //= (5: ~bigfloat)
$$ETIME-ELECTIVE //= (-3: uint) $$ETIME-ELECTIVE //= (-3: uint)
$$ETIME-ELECTIVE //= (-6: uint) $$ETIME-ELECTIVE //= (-6: uint)
$$ETIME-ELECTIVE //= (-9: uint) $$ETIME-ELECTIVE //= (-9: uint)
$$ETIME-ELECTIVE //= (-12: uint) $$ETIME-ELECTIVE //= (-12: uint)
$$ETIME-ELECTIVE //= (-15: uint) $$ETIME-ELECTIVE //= (-15: uint)
$$ETIME-ELECTIVE //= (-18: uint) $$ETIME-ELECTIVE //= (-18: uint)
$$ETIME-ELECTIVE //= (-1 => $ETIME-TIMESCALE) $$ETIME-ELECTIVE //= (-1 => $ETIME-TIMESCALE)
$$ETIME-ELECTIVE //= (-13 => $ETIME-TIMESCALE)
$$ETIME-CRITICAL //= (13 => $ETIME-TIMESCALE)
$ETIME-TIMESCALE /= &(etime-utc: 0) $ETIME-TIMESCALE /= &(etime-utc: 0)
$ETIME-TIMESCALE /= &(etime-tai: 1) $ETIME-TIMESCALE /= &(etime-tai: 1)
ClockQuality-group = ( ClockQuality-group = (
? &(ClockClass: -2) => uint .size 1 ; PTP/RFC8575 ? &(ClockClass: -2) => uint .size 1 ; PTP/RFC8575
? &(ClockAccuracy: -4) => uint .size 1 ; PTP/RFC8575 ? &(ClockAccuracy: -4) => uint .size 1 ; PTP/RFC8575
? &(OffsetScaledLogVariance: -5) => uint .size 2 ; PTP/RFC8575 ? &(OffsetScaledLogVariance: -5) => uint .size 2 ; PTP/RFC8575
? &(Uncertainty: -7) => ~time/~duration ? &(Uncertainty: -7) => ~time/~duration
? &(Guarantee: -8) => ~time/~duration ? &(Guarantee: -8) => ~time/~duration
skipping to change at line 1366 skipping to change at line 1281
time-zone-info = tstr .abnf time-zone-info = tstr .abnf
("time-zone-name / time-numoffset" .det IXDTFtz) ("time-zone-name / time-numoffset" .det IXDTFtz)
IXDTFtz = ' IXDTFtz = '
time-hour = 2DIGIT ; 00-23 time-hour = 2DIGIT ; 00-23
time-minute = 2DIGIT ; 00-59 time-minute = 2DIGIT ; 00-59
time-numoffset = ("+" / "-") time-hour ":" time-minute time-numoffset = ("+" / "-") time-hour ":" time-minute
time-zone-initial = ALPHA / "." / "_" time-zone-initial = ALPHA / "." / "_"
time-zone-char = time-zone-initial / DIGIT / "-" / "+" time-zone-char = time-zone-initial / DIGIT / "-" / "+"
time-zone-part = time-zone-initial *13(time-zone-char) time-zone-part = time-zone-initial *time-zone-char
; but not "." or ".." ; but not "." or ".."
time-zone-name = time-zone-part *("/" time-zone-part) time-zone-name = time-zone-part *("/" time-zone-part)
ALPHA = %x41-5A / %x61-7A ; A-Z / a-z ALPHA = %x41-5A / %x61-7A ; A-Z / a-z
DIGIT = %x30-39 ; 0-9 DIGIT = %x30-39 ; 0-9
' ; extracted from [IXDTF] and [RFC3339]; update as needed ' ; extracted from [RFC9557] and [RFC3339]
$$ETIME-ELECTIVE //= (-11: suffix-info-map) $$ETIME-ELECTIVE //= (-11: suffix-info-map)
$$ETIME-CRITICAL //= (11: suffix-info-map) $$ETIME-CRITICAL //= (11: suffix-info-map)
suffix-info-map = { * suffix-key => suffix-values } suffix-info-map = { * suffix-key => suffix-values }
suffix-key = tstr .abnf ("suffix-key" .det IXDTF) suffix-key = tstr .abnf ("suffix-key" .det IXDTF)
suffix-values = one-or-more<suffix-value> suffix-values = one-or-more<suffix-value>
one-or-more<T> = T / [ 2* T ] one-or-more<T> = T / [ 2* T ]
suffix-value = tstr .abnf ("suffix-value" .det IXDTF) suffix-value = tstr .abnf ("suffix-value" .det IXDTF)
IXDTF = ' IXDTF = '
key-initial = lcalpha / "_" key-initial = lcalpha / "_"
key-char = key-initial / DIGIT / "-" key-char = key-initial / DIGIT / "-"
suffix-key = key-initial *key-char suffix-key = key-initial *key-char
suffix-value = 1*alphanum suffix-value = 1*alphanum
alphanum = ALPHA / DIGIT alphanum = ALPHA / DIGIT
lcalpha = %x61-7A lcalpha = %x61-7A
ALPHA = %x41-5A / %x61-7A ; A-Z / a-z ALPHA = %x41-5A / %x61-7A ; A-Z / a-z
DIGIT = %x30-39 ; 0-9 DIGIT = %x30-39 ; 0-9
' ; extracted from [IXDTF]; update as needed! ' ; extracted from [RFC9557]
Duration = #6.1002(etime-detailed) Duration = #6.1002(etime-detailed)
Period = #6.1003([ simple-Period = #6.1003([
start: ~Etime / null start: ~Etime / null
end: ~Etime / null end: ~Etime / null
? duration: ~Duration / null ? duration: ~Duration
]) ])
clumsy-Period = #6.1003([ Period = #6.1003([
(start: ~Etime, (start: ~Etime,
((end: ~Etime, ((end: ~Etime) //
? duration: null) //
(end: null, (end: null,
duration: ~Duration))) // duration: ~Duration))) //
(start: null, (start: null,
end: ~Etime, end: ~Etime,
duration: ~Duration) duration: ~Duration)
]) ])
etime = #6.1001({* (int/tstr) => any}) etime = #6.1001({* (int/tstr) => any})
duration = #6.1002({* (int/tstr) => any}) duration = #6.1002({* (int/tstr) => any})
period = #6.1003([~etime/null, ~etime/null, ~duration/null]) period = #6.1003([~etime/null, ~etime/null, ?~duration])
]]></sourcecode> ]]></sourcecode>
</figure> </figure>
</section> </section>
<section anchor="acknowledgements" numbered="false"> <section anchor="acknowledgements" numbered="false">
<name>Acknowledgements</name> <name>Acknowledgements</name>
<t>The authors would like to acknowledge the many comments from members <t>The authors would like to acknowledge the many comments from members
of the CBOR WG, of the CBOR WG,
<contact fullname="Francesca Palombini"/> for her AD review, and <contact fullname="Francesca Palombini"/> for her AD review,
<contact fullname="Thomas Fossati"/> and <contact fullname="Thomas Fossati"/> and
<contact fullname="Qin Wu"/> for their directorate reviews.</t> <contact fullname="Qin Wu"/> for their directorate reviews, and <contact fullnam
e="Rohan Mahy"/> for one more review late in the process.</t>
<!-- LocalWords: CBOR extensibility IANA uint sint IEEE endian TAI <!-- LocalWords: CBOR extensibility IANA uint sint IEEE endian TAI
--> -->
<!-- LocalWords: signedness endianness NTP IXDTF <!-- LocalWords: signedness endianness NTP IXDTF
--> -->
</section> </section>
</back> </back>
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