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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<META http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>XEP-0323: Internet of Things - Sensor Data</title>
<link rel="stylesheet" type="text/css" href="xmpp.css">
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<meta name="DC.Title" content="Internet of Things - Sensor Data">
<meta name="DC.Creator" content="Peter Waher">
<meta name="DC.Description" content="This specification provides the common framework for sensor data interchange over XMPP networks.">
<meta name="DC.Publisher" content="XMPP Standards Foundation">
<meta name="DC.Contributor" content="XMPP Extensions Editor">
<meta name="DC.Date" content="2014-03-31">
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<meta name="DC.Identifier" content="XEP-0323">
<meta name="DC.Language" content="en">
<meta name="DC.Rights" content="This XMPP Extension Protocol is copyright © 1999 - 2014 by the XMPP Standards Foundation (XSF).">
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<body onload="prettyPrint()">
<h1>XEP-0323: Internet of Things - Sensor Data</h1>
<table>
<tr valign="top">
<td><strong>Abstract:</strong></td>
<td>This specification provides the common framework for sensor data interchange over XMPP networks.</td>
</tr>
<tr valign="top">
<td><strong>Author:</strong></td>
<td>Peter Waher</td>
</tr>
<tr valign="top">
<td><strong>Copyright:</strong></td>
<td>© 1999 - 2014 XMPP Standards Foundation. <a href="#appendix-legal">SEE LEGAL NOTICES</a>.</td>
</tr>
<tr valign="top">
<td><strong>Status:</strong></td>
<td>Experimental</td>
</tr>
<tr valign="top">
<td><strong>Type:</strong></td>
<td>Standards Track</td>
</tr>
<tr valign="top">
<td><strong>Version:</strong></td>
<td>0.4</td>
</tr>
<tr valign="top">
<td><strong>Last Updated:</strong></td>
<td>2014-03-31</td>
</tr>
</table>
<hr>
<p style="color:red">WARNING: This Standards-Track document is Experimental. Publication as an XMPP Extension Protocol does not imply approval of this proposal by the XMPP Standards Foundation. Implementation of the protocol described herein is encouraged in exploratory implementations, but production systems are advised to carefully consider whether it is appropriate to deploy implementations of this protocol before it advances to a status of Draft.</p>
<hr>
<h2>Table of Contents</h2>
<div class="indent">
<p><br>1. <a href="#intro">Introduction</a><br>2. <a href="#glossary">Glossary</a><br>3. <a href="#usecases">Use Cases</a><br>
3.1. <a href="#readmomentary">Request Read-out of momentary values</a><br>
3.2. <a href="#readoutfailure">Read-out failure</a><br>
3.3. <a href="#readoutrejected">Read-out rejected</a><br>
3.4. <a href="#readall">Read-out all</a><br>
3.5. <a href="#readmulti">Read-out of multiple devices</a><br>
3.6. <a href="#readfields">Read-out of specific fields</a><br>
3.7. <a href="#cancelreadout">Cancelling a scheduled read-out request</a><br>4. <a href="#support">Determining Support</a><br>5. <a href="#impl">Implementation Notes</a><br>
5.1. <a href="#stringlengths">String lengths</a><br>
5.2. <a href="#enumsvsstrings">Enumerations vs. Strings</a><br>
5.3. <a href="#asynchfeedback">Asynchronous feedback</a><br>
5.4. <a href="#fieldvaluetypes">Field Value Data Types</a><br>
5.5. <a href="#harmonization">Harmonization with XEP-0325 (Control)</a><br>
5.6. <a href="#fieldtypes">Field Types</a><br>
5.7. <a href="#fieldqosvalues">Field Quality of Service Values</a><br>
5.7.1. <a href="#estimatesvsreadouts">Estimates vs. Readouts</a><br>
5.8. <a href="#subsupernodes">Subnodes and supernodes</a><br>
5.9. <a href="#largesubsystems">Reading devices from large subsystems</a><br>
5.10. <a href="#control">Reading controllable parameter values</a><br>6. <a href="#i18n">Internationalization Considerations</a><br>
6.1. <a href="#timezones">Time Zones</a><br>
6.2. <a href="#localization">Localized strings</a><br>7. <a href="#security">Security Considerations</a><br>8. <a href="#iana">IANA Considerations</a><br>9. <a href="#registrar">XMPP Registrar Considerations</a><br>10. <a href="#schema">XML Schema</a><br>11. <a href="#moreinfo">For more information</a><br>12. <a href="#ack">Acknowledgements</a></p>
<p><a href="#appendices">Appendices</a><br> <a href="#appendix-docinfo">A: Document Information</a><br> <a href="#appendix-authorinfo">B: Author Information</a><br> <a href="#appendix-legal">C: Legal Notices</a><br> <a href="#appendix-xmpp">D: Relation to XMPP</a><br> <a href="#appendix-discuss">E: Discussion Venue</a><br> <a href="#appendix-conformance">F: Requirements Conformance</a><br> <a href="#appendix-notes">G: Notes</a><br> <a href="#appendix-revs">H: Revision History</a></p>
</div>
<hr>
<h2>1.
<a name="intro">Introduction</a></h2>
<p class="" style="">
This XEP provides the underlying architecture, basic operations and data structures for sensor data communication over XMPP networks. It includes a hardware abstraction model, removing any
technical detail implemented in underlying technologies.
</p>
<p class="" style="">
Note has to be taken, that these XEP's are designed for implementation in sensors, many of which have very limited amount of memory (both RAM and ROM) or resources (processing power).
Therefore, simplicity is of utmost importance. Furthermore, sensor networks can become huge, easily with millions of devices in peer-to-peer networks.
</p>
<p class="" style="">
Sensor networks contains many different architectures and use cases. For this reason, the sensor network standards have been divided into multiple XEPs according to the following table:
</p>
<div class="indent">
<p class="caption"><a name="table-1"></a>Table 1: Internet of Things XEPs</p>
<table border="1" cellpadding="3" cellspacing="0">
<tr class="body">
<th colspan="" rowspan="">XEP</th>
<th colspan="" rowspan="">Description</th>
</tr>
<tr class="body">
<td colspan="" rowspan="">xep-0000-IoT-BatteryPoweredSensors</td>
<td colspan="" rowspan="">Defines how to handle the peculiars related to battery powered devices, and other devices intermittently available on the network.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">xep-0000-IoT-Events</td>
<td colspan="" rowspan="">Defines how sensors send events, how event subscription, hysteresis levels, etc., are configured.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">xep-0000-IoT-Interoperability</td>
<td colspan="" rowspan="">Defines guidelines for how to achieve interoperability in sensor networks, publishing interoperability interfaces for different types of devices.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">xep-0000-IoT-Multicast</td>
<td colspan="" rowspan="">Defines how sensor data can be multicast in efficient ways.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">xep-0000-IoT-PubSub</td>
<td colspan="" rowspan="">Defines how efficient publication of sensor data can be made in sensor networks.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">xep-0000-IoT-Chat</td>
<td colspan="" rowspan="">Defines how human-to-machine interfaces should be constructed using chat messages to be user friendly, automatable and consistent with other IoT extensions and possible underlying architecture.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">XEP-0322</td>
<td colspan="" rowspan="">
Defines how to EXI can be used in XMPP to achieve efficient compression of data. Albeit not a sensor network specific XEP, this XEP should be considered
in all sensor network implementations where memory and packet size is an issue.
</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">XEP-0323</td>
<td colspan="" rowspan="">This specification. Provides the underlying architecture, basic operations and data structures for sensor data communication over XMPP networks.
It includes a hardware abstraction model, removing any technical detail implemented in underlying technologies. This XEP is used by all other sensor network XEPs.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">XEP-0324</td>
<td colspan="" rowspan="">Defines how provisioning, the management of access privileges, etc., can be efficiently and easily implemented.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">XEP-0325</td>
<td colspan="" rowspan="">Defines how to control actuators and other devices in Internet of Things.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">XEP-0326</td>
<td colspan="" rowspan="">Defines how to handle architectures containing concentrators or servers handling multiple sensors.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">XEP-0331</td>
<td colspan="" rowspan="">Defines extensions for how color parameters can be handled, based on <span class="ref" style=""><a href="http://xmpp.org/extensions/xep-0004.html">Data Forms</a></span> [<a href="#nt-ID0ERHAC">1</a>]</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">XEP-0336</td>
<td colspan="" rowspan="">Defines extensions for how dynamic forms can be created, based on <span class="ref" style=""><a href="http://xmpp.org/extensions/xep-0004.html">Data Forms</a></span> [<a href="#nt-ID0EIIAC">2</a>], <span class="ref" style=""><a href="http://xmpp.org/extensions/xep-0122.html">Data Forms Validation</a></span> [<a href="#nt-ID0EUIAC">3</a>], <span class="ref" style=""><a href="http://xmpp.org/extensions/xep-0137.html">Publishing Stream Initiation Requests</a></span> [<a href="#nt-ID0EAJAC">4</a>] and <span class="ref" style=""><a href="http://xmpp.org/extensions/xep-0141.html">Data Forms Layout</a></span> [<a href="#nt-ID0EMJAC">5</a>].</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">XEP-0347</td>
<td colspan="" rowspan="">Defines the peculiars of sensor discovery in sensor networks. Apart from discovering sensors by JID, it also defines how to discover sensors based on location, etc.</td>
</tr>
</table>
</div>
<h2>2.
<a name="glossary">Glossary</a></h2>
<p class="" style="">The following table lists common terms and corresponding descriptions.</p>
<div class="indent">
<dl>
<di>
<dt><strong>Actuator</strong></dt>
<dd>Device containing at least one configurable property or output that can and should be controlled by some other entity or device.</dd>
</di>
<di>
<dt><strong>Computed Value</strong></dt>
<dd>A value that is computed instead of measured.</dd>
</di>
<di>
<dt><strong>Concentrator</strong></dt>
<dd>Device managing a set of devices which it publishes on the XMPP network.</dd>
</di>
<di>
<dt><strong>Field</strong></dt>
<dd>One item of sensor data. Contains information about: Node, Field Name, Value, Precision, Unit, Value Type, Status, Timestamp, Localization information, etc.
Fields should be unique within the triple (Node ID, Field Name, Timestamp).</dd>
</di>
<di>
<dt><strong>Field Name</strong></dt>
<dd>Name of a field of sensor data. Examples: Energy, Volume, Flow, Power, etc.</dd>
</di>
<di>
<dt><strong>Field Type</strong></dt>
<dd>What type of value the field represents. Examples: Momentary Value, Status Value, Identification Value, Calculated Value, Peak Value, Historical Value, etc.</dd>
</di>
<di>
<dt><strong>Historical Value</strong></dt>
<dd>A value stored in memory from a previous timestamp.</dd>
</di>
<di>
<dt><strong>Identification Value</strong></dt>
<dd>A value that can be used for identification. (Serial numbers, meter IDs, locations, names, etc.)</dd>
</di>
<di>
<dt><strong>Localization information</strong></dt>
<dd>Optional information for a field, allowing the sensor to control how the information should be presented to human viewers.</dd>
</di>
<di>
<dt><strong>Meter</strong></dt>
<dd>A device possible containing multiple sensors, used in metering applications. Examples: Electricity meter, Water Meter, Heat Meter, Cooling Meter, etc.</dd>
</di>
<di>
<dt><strong>Momentary Value</strong></dt>
<dd>A momentary value represents a value measured at the time of the read-out.</dd>
</di>
<di>
<dt><strong>Node</strong></dt>
<dd>
Graphs contain nodes and edges between nodes. In Internet of Things, sensors, actuators, meters, devices, gateways, etc., are often depicted as nodes whereas links between sensors (friendships)
are depicted as edges. In abstract terms, it's easier to talk about a Node, rather than list different possible node types (sensors, actuators, meters, devices, gateways, etc.).
Each Node has a Node ID.</dd>
</di>
<di>
<dt><strong>Node ID</strong></dt>
<dd>An ID uniquely identifying a node within its corresponding context. If a globally unique ID is desired, an architecture should be used using a universally accepted
ID scheme.</dd>
</di>
<di>
<dt><strong>Parameter</strong></dt>
<dd>Readable and/or writable property on a node/device. The XEP-0326 <span class="ref" style=""><a href="http://xmpp.org/extensions/xep-0326.html">Internet of Things - Concentrators</a></span> [<a href="#nt-ID0ESNAC">6</a>] deals with reading and writing parameters
on nodes/devices. Fields are not parameters, and parameters are not fields.</dd>
</di>
<di>
<dt><strong>Peak Value</strong></dt>
<dd>A maximum or minimum value during a given period.</dd>
</di>
<di>
<dt><strong>Precision</strong></dt>
<dd>In physics, precision determines the number of digits of precision. In sensor networks however, this definition is not easily applicable. Instead, precision
determines, for example, the number of decimals of precision, or power of precision. Example: 123.200 MWh contains 3 decimals of precision. All entities parsing and
delivering field information in sensor networks should always retain the number of decimals in a message.</dd>
</di>
<di>
<dt><strong>Sensor</strong></dt>
<dd>Device measuring at least one digital value (0 or 1) or analog value (value with precision and physical unit). Examples: Temperature sensor, pressure sensor, etc.
Sensor values are reported as fields during read-out. Each sensor has a unique Node ID.</dd>
</di>
<di>
<dt><strong>SN</strong></dt>
<dd>Sensor Network. A network consisting, but not limited to sensors, where transport and use of sensor data is of primary concern. A sensor network may contain actuators, network applications, monitors, services, etc.</dd>
</di>
<di>
<dt><strong>Status Value</strong></dt>
<dd>A value displaying status information about something.</dd>
</di>
<di>
<dt><strong>Timestamp</strong></dt>
<dd>Timestamp of value, when the value was sampled or recorded.</dd>
</di>
<di>
<dt><strong>Token</strong></dt>
<dd>
A client, device or user can get a token from a provisioning server. These tokens can be included in requests to other entities in the network, so these entities can validate
access rights with the provisioning server.
</dd>
</di>
<di>
<dt><strong>Unit</strong></dt>
<dd>Physical unit of value. Example: MWh, l/s, etc.</dd>
</di>
<di>
<dt><strong>Value</strong></dt>
<dd>A field value.</dd>
</di>
<di>
<dt><strong>Value Status</strong></dt>
<dd>Status of field value. Contains important status information for Quality of Service purposes. Examples: Ok, Error, Warning, Time Shifted, Missing, Signed, etc.</dd>
</di>
<di>
<dt><strong>Value Type</strong></dt>
<dd>Can be numeric, string, boolean, Date & Time, Time Span or Enumeration.</dd>
</di>
<di>
<dt><strong>WSN</strong></dt>
<dd>Wireless Sensor Network, a sensor network including wireless devices.</dd>
</di>
<di>
<dt><strong>XMPP Client</strong></dt>
<dd>Application connected to an XMPP network, having a JID. Note that sensors, as well as applications requesting sensor data can be XMPP clients.</dd>
</di>
</dl>
</div>
<h2>3.
<a name="usecases">Use Cases</a></h2>
<p class="" style="">
The most common use case for a sensor network application is meter read-out. It's performed using a request and response mechanism, as is shown in the following diagram.
</p>
<p class="" style="">
<img alt="" src="data:image/png;base64,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">
</p>
<p class="" style="">
The read-out request is started by the client sending a <span class="strong">req</span> request to the device. Here, the client selects a sequence number <span class="strong">seqnr</span>.
It should be unique among requests made by the client. The device will use this sequence numbers in all messages sent back to the client.
</p>
<p class="" style="">
The request also contains a set of <span class="strong">field types</span> that very roughly determine what the client wants to read. What the client actually will return will be determined by
a lot of other factors, such as make and model of device, any provisioning rules provided, etc. This parameter just gives a hint on what kind of data is desired. It is implicit in the request
by the context what kind of data is requested. Examples of field types are: Momentary values, peak values, historical values, computed values, status values, identification values, etc.
</p>
<p class="" style="">
If reading historical values, the client can also specify an optional time range using the <span class="strong">from</span> and <span class="strong">to</span> parameter values, giving the device a hint on
how much data to return.
</p>
<p class="" style="">
If the client wants the read-out to be performed at a given point in time, the client can define this using the optional parameter <span class="strong">when</span>.
</p>
<p class="" style="">
There's an optional parameter <span class="strong">ids</span> that the client can provide, listing a set of <span class="strong">Node IDs</span>. If omitted, the request includes all sensors or devices
managed by the current JID. But, if the JID is controlled by a system, device or concentrator managing various devices, the <span class="strong">ids</span> parameter restricts the read-out to
specific individuals.
</p>
<p class="" style="">
<span class="strong">Note:</span> The device is not required to follow the hints given by the client. These are suggestions the client can use to minimize its effort to perform the read-out.
The client MUST make sure the response is filtered according to original requirements by the client after the read-out response has been received.
</p>
<p class="" style="">
If the device accepts the client request, it sends an <span class="strong">accepted</span> response back to the client. The device also has to determine if the read-out is commenced directly,
or if it is to be queued for later processing. Note that the request can be queued for several reasons. The device can be busy, and queues it until it is ready to process the request.
It can also queue the request if the client has requested it to be executed at a given time. If the request is queued, the device informs the client of this using the <span class="strong">queued</span>
attribute. Note however, that the device will process the request when it can. There's no guarantee that the device will be able to process the request exactly when the client requests it.
</p>
<p class="" style="">
<span class="strong">Note:</span> The <span class="strong">accepted</span> message can be omitted if the device already has the response and is ready to send it. If the client receives field data or a
<span class="strong">done</span> message before receiving an <span class="strong">accepted</span> message, the client can assume the device accepted the request and omitted sending an <span class="strong">accepted</span>
element.
</p>
<p class="" style="">
If the request was queued, the device will send a message informing the client when the read-out is begun. This is done using a <span class="strong">started</span> message, using the same
<span class="strong">seqnr</span> used in the original request.
</p>
<p class="" style="">
<span class="strong">Note:</span> Sending a <span class="strong">started</span> element should be omitted by the device if the request is not queued on the device. If the <span class="strong">queued</span> attribute
is omitted in the response, or has the value <span class="strong">false</span>, the client must not assume the device will send a <span class="strong">started</span> element.
</p>
<p class="" style="">
During the read-out, the device sends partial results back to the client using the same <span class="strong">seqnr</span> as used in the request, using a <span class="strong">fields</span> message.
These messages will contain a sequence of fields read out of the device. The client is required to filter this list according to original specifications, as the device is not required
to do this filtering for the client.
</p>
<p class="" style="">
When read-out is complete, the device will send a <span class="strong">done</span> message to the client with the same <span class="strong">seqnr</span> as in the original request. Since the sender
of messages in the device at the time of sending might not be aware of if there are more messages to send or not, the device can send this message separately as is shown in the
diagram. If the device however, knows the last message containing fields is the last, it can set a <span class="strong">done</span> attribute in the message, to skip this last message.
</p>
<p class="" style="">
<span class="strong">Note:</span> There is no guarantee that the device will send a corresponding <span class="strong">started</span> and <span class="strong">fields</span> element, even though the request was
accepted. The device might lose power during the process and forget the request. The client should always be aware of that devices may not respond in time, and take appropriate action
accordingly (for instance, implementing a retry mechanism).
</p>
<p class="" style="">
If a failure occurs while performing the read-out, a <span class="strong">failure</span> message is sent, instead of a corresponding <span class="strong">fields</span> message, as is shown in the following diagram.
Apart from notifying the client that a failure to perform the read-out, or part thereof, has occurred, it also provides a list of errors that the device encountered while trying. Note that
multiple <span class="strong">fields</span> and <span class="strong">failure</span> messages can be sent back to the client during the read-out.
</p>
<p class="" style="">
<img alt="" src="data:image/png;base64,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">
</p>
<p class="" style="">
The device can also reject a read-out request. Reasons for rejecting a request may be missing privileges defined by provisioning rules, etc. It's not part of this XEP
to define such rules. A separate XEP (<span class="ref" style=""><a href="http://xmpp.org/extensions/xep-0324.html">Internet of Things - Provisioning</a></span> [<a href="#nt-ID0EIGAE">7</a>]) defines an architecture for how such provisioning can be easily implemented.
</p>
<p class="" style="">
A rejection response is shown in the following diagram.
</p>
<p class="" style="">
<img alt="" src="data:image/png;base64,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">
</p>
<p class="" style="">
If a read-out has been queued, the client can cancel the queued read-out request sending a <span class="strong">cancel</span> command to the device. If a reading has begin and the client
sends a <span class="strong">cancel</span> command to the device, the device can choose if the read-out should be cancelled or completed.
</p>
<p class="" style="">
<span class="strong">Note:</span> Remember that the <span class="strong">seqnr</span> value used in this command is unique only to the client making the request. The device can receive requests
from multiple clients, and must make sure it differs between <span class="strong">seqnr</span> values from different clients. Different clients are assumed to have different values
in the corresponding <span class="strong">from</span> attributes.
</p>
<p class="" style="">
<img alt="" src="data:image/png;base64,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">
</p>
<div class="indent">
<h3>3.1 <a name="readmomentary">Request Read-out of momentary values</a></h3>
<p class="" style="">
The client that wishes to receive momentary values from the sensor initiates the request using the <span class="strong">req</span> element sent to the device.
</p>
<p class="caption"><a name="example-1"></a>Example 1. Read-out request of momentary values from a device</p>
<div class="indent">
<pre class="prettyprint">
<iq type='get'
from='client@clayster.com/amr'
to='device@clayster.com'
id='S0001'>
<req xmlns='urn:xmpp:iot:sensordata' seqnr='1' momentary='true'/>
</iq>
</pre>
</div>
<p class="" style="">
When the device has received and accepted the request, it responds as follows:
</p>
<p class="caption"><a name="example-2"></a>Example 2. Read-out request accepted by device</p>
<div class="indent">
<pre class="prettyprint">
<iq type='result'
from='device@clayster.com'
to='client@clayster.com/amr'
id='S0001'>
<accepted xmlns='urn:xmpp:iot:sensordata' seqnr='1'/>
</iq>
</pre>
</div>
<p class="" style="">
When read-out is complete, the response is sent as follows:
</p>
<p class="caption"><a name="example-3"></a>Example 3. Momentary read-out response</p>
<div class="indent">
<pre class="prettyprint">
<message from='device@clayster.com'
to='client@clayster.com/amr'>
<fields xmlns='urn:xmpp:iot:sensordata' seqnr='1' done='true'>
<node nodeId='Device01'>
<timestamp value='2013-03-07T16:24:30'>
<numeric name='Temperature' momentary='true' automaticReadout='true' value='23.4' unit='°C'/>
</timestamp>
</node>
</fields>
</message>
</pre>
</div>
</div>
<div class="indent">
<h3>3.2 <a name="readoutfailure">Read-out failure</a></h3>
<p class="" style="">
If instead a read-out could not be performed, the communication sequence might look as follows:
</p>
<p class="caption"><a name="example-4"></a>Example 4. Momentary read-out failure</p>
<div class="indent">
<pre class="prettyprint">
<iq type='get'
from='client@clayster.com/amr'
to='device@clayster.com'
id='S0002'>
<req xmlns='urn:xmpp:iot:sensordata' seqnr='2' momentary='true'/>
</iq>
<iq type='result'
from='device@clayster.com'
to='client@clayster.com/amr'
id='S0002'>
<accepted xmlns='urn:xmpp:iot:sensordata' seqnr='2'/>
</iq>
<message from='device@clayster.com'
to='client@clayster.com/amr'>
<failure xmlns='urn:xmpp:iot:sensordata' seqnr='2' done='true'>
<error nodeId='Device01' timestamp='2013-03-07T17:13:30'>Timeout.</error>
</failure>
</message>
</pre>
</div>
</div>
<div class="indent">
<h3>3.3 <a name="readoutrejected">Read-out rejected</a></h3>
<p class="" style="">
If for some reason, the device rejects the read-out request, the communication sequence might look as follows:
</p>
<p class="caption"><a name="example-5"></a>Example 5. Momentary read-out rejected</p>
<div class="indent">
<pre class="prettyprint">
<iq type='get'
from='client@clayster.com/amr'
to='device@clayster.com'
id='S0003'>
<req xmlns='urn:xmpp:iot:sensordata' seqnr='3' momentary='true'/>
</iq>
<iq type='error'
from='device@clayster.com'
to='client@clayster.com/amr'
id='S0003'>
<error type='cancel'>
<forbidden xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'/>
<text xmlns='urn:ietf:params:xml:ns:xmpp-stanzas' xml:lang='en'>Access denied.</text>
</error>
</iq>
</pre>
</div>
<p class="" style="">
Depending on the reason for rejecting the request, different XMPP errors can be returned, according to the description in the following table. The table also
lists recommended error type for each error. Any custom error message is returned in a <span class="strong">text</span> element, as in the example above.
</p>
<div class="indent">
<p class="caption"><a name="table-2"></a>Table 2: XMPP Errors when rejecting a readout request</p>
<table border="1" cellpadding="3" cellspacing="0">
<tr class="body">
<th colspan="" rowspan="">Error Type</th>
<th colspan="" rowspan="">Error Element</th>
<th colspan="" rowspan="">Namespace</th>
<th colspan="" rowspan="">Description</th>
</tr>
<tr class="body">
<td colspan="" rowspan="">cancel</td>
<td colspan="" rowspan="">forbidden</td>
<td colspan="" rowspan="">urn:ietf:params:xml:ns:xmpp-stanzas</td>
<td colspan="" rowspan="">If the caller lacks privileges to perform the action.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">cancel</td>
<td colspan="" rowspan="">item-not-found</td>
<td colspan="" rowspan="">urn:ietf:params:xml:ns:xmpp-stanzas</td>
<td colspan="" rowspan="">If an item or data source could not be found.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">modify</td>
<td colspan="" rowspan="">bad-request</td>
<td colspan="" rowspan="">urn:ietf:params:xml:ns:xmpp-stanzas</td>
<td colspan="" rowspan="">If the request was malformed. Examples can include trying to read a device behind a concentrator, without including node information.</td>
</tr>
</table>
</div>
</div>
<div class="indent">
<h3>3.4 <a name="readall">Read-out all</a></h3>
<p class="" style="">
The following example shows a communication sequence when a client reads out all available information from a sensor at a given point in time:
</p>
<p class="caption"><a name="example-6"></a>Example 6. Scheduled read-out of device with multiple responses</p>
<div class="indent">
<pre class="prettyprint">
<iq type='get'
from='client@clayster.com/amr'
to='device@clayster.com'
id='S0004'>
<req xmlns='urn:xmpp:iot:sensordata' seqnr='4' all='true' when='2013-03-07T19:00:00'/>
</iq>
<iq type='result'
from='device@clayster.com'
to='client@clayster.com/amr'
id='S0004'>
<accepted xmlns='urn:xmpp:iot:sensordata' seqnr='4' queued='true'/>
</iq>
<message from='device@clayster.com'
to='client@clayster.com/amr'>
<started xmlns='urn:xmpp:iot:sensordata' seqnr='4'/>
</message>
<message from='device@clayster.com'
to='client@clayster.com/amr'>
<fields xmlns='urn:xmpp:iot:sensordata' seqnr='4'>
<node nodeId='Device01'>
<timestamp value='2013-03-07T19:00:00'>
<numeric name='Temperature' momentary='true' automaticReadout='true' value='23.4' unit='°C'/>
<numeric name='Runtime' status='true' automaticReadout='true' value='12345' unit='h'/>
<string name='Device ID' identification='true' automaticReadout='true' value='Device01'/>
</timestamp>
</node>
</fields>
</message>
<message from='device@clayster.com'
to='client@clayster.com/amr'>
<fields xmlns='urn:xmpp:iot:sensordata' seqnr='4'>
<node nodeId='Device01'>
<timestamp value='2013-03-07T19:00:00'>
<numeric name='Temperature, Max' peak='true' automaticReadout='true' value='25.9' unit='°C'/>
<numeric name='Temperature, Min' peak='true' automaticReadout='true' value='18.7' unit='°C'/>
<numeric name='Temperature, Mean' computed='true' automaticReadout='true' value='22.5' unit='°C'/>
</timestamp>
</node>
</fields>
</message>
<message from='device@clayster.com'
to='client@clayster.com/amr'>
<fields xmlns='urn:xmpp:iot:sensordata' seqnr='4'>
<node nodeId='Device01'>
<timestamp value='2013-03-07T18:00:00'>
<numeric name='Temperature' historicalHour='true' automaticReadout='true' value='24.5' unit='°C'/>
</timestamp>
<timestamp value='2013-03-07T17:00:00'>
<numeric name='Temperature' historicalHour='true' automaticReadout='true' value='25.1' unit='°C'/>
</timestamp>
<timestamp value='2013-03-07T16:00:00'>
<numeric name='Temperature' historicalHour='true' automaticReadout='true' value='25.2' unit='°C'/>
</timestamp>
...
<timestamp value='2013-03-07T00:00:00'>
<numeric name='Temperature' historicalHour='true' historicalDay='true' automaticReadout='true' value='25.2' unit='°C'/>
</timestamp>
</node>
</fields>
</message>
<message from='device@clayster.com'
to='client@clayster.com/amr'>
<done xmlns='urn:xmpp:iot:sensordata' seqnr='4'/>
</message>
</pre>
</div>
</div>
<div class="indent">
<h3>3.5 <a name="readmulti">Read-out of multiple devices</a></h3>
<p class="" style="">
The following example shows how a client reads a subset of multiple sensors behind a device with a single JID.
</p>
<p class="caption"><a name="example-7"></a>Example 7. Read-out of multiple devices</p>
<div class="indent">
<pre class="prettyprint">
<iq type='get'
from='client@clayster.com/amr'
to='device@clayster.com'
id='S0005'>
<req xmlns='urn:xmpp:iot:sensordata' seqnr='5' momentary='true'>
<node nodeId='Device02'/>
<node nodeId='Device03'/>
</req>
</iq>
<iq type='result'
from='device@clayster.com'
to='client@clayster.com/amr'
id='S0005'>
<accepted xmlns='urn:xmpp:iot:sensordata' seqnr='5'/>
</iq>
<message from='device@clayster.com'
to='client@clayster.com/amr'>
<fields xmlns='urn:xmpp:iot:sensordata' seqnr='5'>
<node nodeId='Device02'>
<timestamp value='2013-03-07T19:31:15'>
<numeric name='Temperature' momentary='true' automaticReadout='true' value='23.4' unit='°C'/>
</timestamp>
</node>
</fields>
</message>
<message from='device@clayster.com'
to='client@clayster.com/amr'>
<fields xmlns='urn:xmpp:iot:sensordata' seqnr='5' done='true'>
<node nodeId='Device03'>
<timestamp value='2013-03-07T19:31:16'>
<numeric name='Temperature' momentary='true' automaticReadout='true' value='22.8' unit='°C'/>
</timestamp>
</node>
</fields>
</message>
</pre>
</div>
</div>
<div class="indent">
<h3>3.6 <a name="readfields">Read-out of specific fields</a></h3>
<p class="" style="">
The <span class="strong">req</span> element can take <span class="strong">field</span> sub elements, with which the client can specify which fields it is interested in.
If not provided, the client is assumed to return all matching fields, regardless of field name. However, the <span class="strong">field</span> elements in the
request object can be used as a hint which fields should be returned.
</p>
<p class="" style="">
<span class="strong">Note:</span> the device is not required to adhere to the field limits expressed by these <span class="strong">field</span> elements. They are considered
a hint the device can use to limit bandwidth.
</p>
<p class="" style="">
The following example shows how a client can read specific fields in a device.
</p>
<p class="caption"><a name="example-8"></a>Example 8. Read-out of multiple devices</p>
<div class="indent">
<pre class="prettyprint">
<iq type='get'
from='client@clayster.com/amr'
to='device@clayster.com'
id='S0006'>
<req xmlns='urn:xmpp:iot:sensordata' seqnr='6' momentary='true'>
<node nodeId='Device04'/>
<field name='Energy'/>
<field name='Power'/>
</req>
</iq>
<iq type='result'
from='device@clayster.com'
to='client@clayster.com/amr'
id='S0006'>
<accepted xmlns='urn:xmpp:iot:sensordata' seqnr='6'/>
</iq>
<message from='device@clayster.com'
to='client@clayster.com/amr'>
<fields xmlns='urn:xmpp:iot:sensordata' seqnr='6' done='true'>
<node nodeId='Device04'>
<timestamp value='2013-03-07T22:03:15'>
<numeric name='Energy' momentary='true' automaticReadout='true' value='12345.67' unit='MWh'/>
<numeric name='Power' momentary='true' automaticReadout='true' value='239.4' unit='W'/>
</timestamp>
</node>
</fields>
</message>
</pre>
</div>
</div>
<div class="indent">
<h3>3.7 <a name="cancelreadout">Cancelling a scheduled read-out request</a></h3>
<p class="" style="">
The following example shows how the client cancels a scheduled read-out:
</p>
<p class="caption"><a name="example-9"></a>Example 9. Scheduled read-out of device with multiple responses</p>
<div class="indent">
<pre class="prettyprint">
<iq type='get'
from='client@clayster.com/amr'
to='device@clayster.com'
id='S0007'>
<req xmlns='urn:xmpp:iot:sensordata' seqnr='8' all='true' when='2013-03-09T23:30:00'/>
</iq>
<iq type='result'
from='device@clayster.com'
to='client@clayster.com/amr'
id='S0007'>
<accepted xmlns='urn:xmpp:iot:sensordata' seqnr='8' queued='true'/>
</iq>
<iq type='get'
from='client@clayster.com/amr'
to='device@clayster.com'
id='S0008'>
<cancel xmlns='urn:xmpp:iot:sensordata' seqnr='8'/>
</iq>
<iq type='result'
from='device@clayster.com'
to='client@clayster.com/amr'
id='S0008'>
<cancelled xmlns='urn:xmpp:iot:sensordata' seqnr='8'/>
</iq>
</pre>
</div>
</div>
<h2>4.
<a name="support">Determining Support</a></h2>
<p class="" style="">If an entity supports the protocol specified herein, it MUST advertise that fact by returning a feature of "urn:xmpp:iot:sensordata" in response to <span class="ref" style=""><a href="http://xmpp.org/extensions/xep-0030.html">Service Discovery</a></span> [<a href="#nt-ID0EYOAE">8</a>] information requests.</p>
<p class="caption"><a name="example-10"></a>Example 10. Service discovery information request</p>
<div class="indent">
<pre class="prettyprint">
<iq type='get'
from='client@clayster.com/amr'
to='device@clayster.com'
id='disco1'>
<query xmlns='http://jabber.org/protocol/disco#info'/>
</iq>
</pre>
</div>
<p class="caption"><a name="example-11"></a>Example 11. Service discovery information response</p>
<div class="indent">
<pre class="prettyprint">
<iq type='result'
from='device@clayster.com'
to='client@clayster.com/amr'
id='disco1'>
<query xmlns='http://jabber.org/protocol/disco#info'>
...
<feature var='urn:xmpp:iot:sensordata'/>
...
</query>
</iq>
</pre>
</div>
<p class="" style="">In order for an application to determine whether an entity supports this protocol, where possible it SHOULD use the dynamic, presence-based profile of service discovery defined
in <span class="ref" style=""><a href="http://xmpp.org/extensions/xep-0115.html">Entity Capabilities</a></span> [<a href="#nt-ID0EPPAE">9</a>]. However, if an application has not received entity capabilities information from an entity, it SHOULD use explicit service discovery instead.</p>
<h2>5.
<a name="impl">Implementation Notes</a></h2>
<div class="indent">
<h3>5.1 <a name="stringlengths">String lengths</a></h3>
<p class="" style="">
As noticed, a conscious effort has been made not to shorten element and attribute names. This is to make sure, XML is maintained readable. Packet size is not deemed to be
affected negatively by this for two reasons:
</p>
<ul class="" style="">
<li class="" style="">For sensors with limited memory, or where package size is important, <span class="ref" style=""><a href="http://xmpp.org/extensions/xep-0322.html">Efficient XML Interchange (EXI) Format</a></span> [<a href="#nt-ID0ERQAE">10</a>] is supposed to be used.
EXI compresses strings as normalized index values, making the string appear only once in the packet. Therefore, shortening string length doesn't affect packet
size much. Element and attribute names in known namespaces are furthermore only encoded by index in schema, not by name.</li>
<li class="" style="">If limited memory or package size is not a consideration, readability and ease of implementation is preferred to short messages.</li>
</ul>
</div>
<div class="indent">
<h3>5.2 <a name="enumsvsstrings">Enumerations vs. Strings</a></h3>
<p class="" style="">
This protocol has avoided the use of enumerations for data types such as units, field names, etc., and instead use strings. The reasons for this are:
</p>
<ul class="" style="">
<li class="" style="">Enumerations would unnecessarily restrict the use of the protocol to field names and units listed in the protocol.</li>
<li class="" style="">It would be very difficult to try to create a complete set of field names and units that would suit all applications.</li>
<li class="" style="">Leaving these values as strings would let developers the liberty to use units as they desire.</li>
<li class="" style="">If EXI is used for compression, the use of strings will only increase payload slightly, with only one copy of each distinct value used.</li>
<li class="" style="">If EXI is not used, this does not affect packet size.</li>
</ul>
<p class="" style="">
However, some things need to be taken into account:
</p>
<ul class="" style="">
<li class="" style="">Since free strings are used, XML validation cannot be used to secure correct names are used.</li>
<li class="" style="">xep-0000-IoT-Interoperability lists recommendations on how field names and units should be used in order to achieve maximum interoperability in SN.</li>
<li class="" style="">Consumers of sensor data need to include unit conversion algorithms.</li>
</ul>
</div>
<div class="indent">
<h3>5.3 <a name="asynchfeedback">Asynchronous feedback</a></h3>
<p class="" style="">
Since some applications require real-time feedback (or as real-time as possible), and read-out might in certain cases take a long time, the device has the option
to send multiple <span class="strong">fields</span> messages during read-out. The client is responsible for collecting all such messages until either a <span class="strong">done</span> message
is sent, or a corresponding <span class="strong">done</span> attribute is available in one of the messages received. Only the device knows how many (if any) messages are sent in
response to a read-out request.
</p>
</div>
<div class="indent">
<h3>5.4 <a name="fieldvaluetypes">Field Value Data Types</a></h3>
<p class="" style="">
There are different types of values that can be reported from a device. The following table lists the various types:
</p>
<div class="indent">
<p class="caption"><a name="table-3"></a>Table 3: Field Value Data Types</p>
<table border="1" cellpadding="3" cellspacing="0">
<tr class="body">
<th colspan="" rowspan="">Element</th>
<th colspan="" rowspan="">Description</th>
</tr>
<tr class="body">
<td colspan="" rowspan="">boolean</td>
<td colspan="" rowspan="">Represents a boolean value that can be either true or false.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">date</td>
<td colspan="" rowspan="">
Represents a date value. The value must be encoded using the xs:date data type.
</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">dateTime</td>
<td colspan="" rowspan="">
Represents a date and optional time value. The value must be encoded using the xs:dateTime data type. This includes date, an optional time and optional time zone information.
If time zone is not available, it is supposed to be undefined.
</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">duration</td>
<td colspan="" rowspan="">Represents a duration value. The value must be encoded using the xs:duration data type.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">enum</td>
<td colspan="" rowspan="">
Represents an enumeration value. What differs this value from a string value, is that it apart from the enumeration value (which is a string value),
also contains a data type, which consumers can use to interpret its value. This specification does not assume knowledge of any particular enumeration
data types.
</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">int</td>
<td colspan="" rowspan="">
Represents a 32-bit integer value. It contains an arbitrary 32-bit integer value. This field value data type can be seen as a subtype of the more generic numeric
field value data type. It has its own element, to make it harmonous to 32-bit integer control parameters, as defined in XEP-0325. It is also simpler to report and
compress, since it does not use floating point precision and a unit.
</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">long</td>
<td colspan="" rowspan="">
Represents a 64-bit integer value. It contains an arbitrary 64-bit integer value. This field value data type can be seen as a subtype of the more generic numeric
field value data type. It has its own element, to make it harmonous to 64-bit integer control parameters, as defined in XEP-0325. It is also simpler to report and
compress, since it does not use floating point precision and a unit.
</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">numeric</td>
<td colspan="" rowspan="">
Represents a numerical value. Numerical values contain, apart from a numerical number, also an implicit precision (number of decimals) and an
optional unit. All parties in the communication chain should retain the number of decimals used, since this contains information that is important
in the interpretation of a value. For example, 10 °C is different from 10.0 °C, and very different from 10.00 °C. If a sensor delivers the value
10 °C you can assume it probably lies between 9.5 °C and 10.5 °C. But if a sensor delivers 10.00 °C, it is probably very exact (if calibrated correctly).
</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">string</td>
<td colspan="" rowspan="">Represents a string value. It contains an arbitrary string value.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">time</td>
<td colspan="" rowspan="">Represents a time value. The value must be encoded using the xs:time data type.</td>
</tr>
</table>
</div>
</div>
<div class="indent">
<h3>5.5 <a name="harmonization">Harmonization with XEP-0325 (Control)</a></h3>
<p class="" style="">
When representing control parameters as momentary field values, it is important to note the similarities and differences between XEP-0323 (this document) and XEP-0325 (Control):
</p>
<p class="" style="">
The <span class="strong">enum</span> field value data type is not available in XEP-0325 (Control). Instead enumeration valued parameters are represented as <span class="strong">string</span> control
parameters, while the control form explicitly lists available options for the parameter. Options are not available in XEP-0323, since it would not be practical to list all options
every time the corresponding parameter was read out. Instead, the <span class="strong">enum</span> element contains a data type attribute, that can be used to identify the type of the enumeration.
</p>
<p class="" style="">
The <span class="strong">numeric</span> field value data type is not available in XEP-0325 (Control). The reason is that a controller is not assumed to understand unit conversion. Any
floating-point valued control parameters are represented by <span class="strong">double</span> control parameters, which lack a unit attribute. They are assumed to have the same unit as
the corresponding <span class="strong">numeric</span> field value. On the other hand, floating point valued control parameters without units, are reported using the <span class="strong">numeric</span>
field element, but leaving the unit blank.
</p>
<p class="" style="">
Control pameters of type <span class="strong">color</span> have no corresponding field value data type. The color value must be represented in another way, and is implementation specific.
Possibilities include representing the color as a string, using a specific pattern (for instance RRGGBBAA), or report it using multiple fields, one for each component for instance.
</p>
<p class="" style="">
The <span class="strong">boolean</span>, <span class="strong">date</span>, <span class="strong">dateTime</span>, <span class="strong">duration</span>, <span class="strong">int</span>, <span class="strong">long</span>, <span class="strong">string</span>
and <span class="strong">time</span> field value data types correspond to control parameters having the same types and same element names.
</p>
</div>
<div class="indent">
<h3>5.6 <a name="fieldtypes">Field Types</a></h3>
<p class="" style="">
There are different types of fields, apart from types of values a field can have. These types are conceptual types, similar to categories. They are not exclusive,
and can be combined.
</p>
<p class="" style="">
If requesting multiple field types in a request, the device must interpret this as a union of the corresponding field types and return at least all field values
that contain at least one of the requested field types. Example: If requesting momentary values and historical values, devices must return both its momentary values
and its historical values.
</p>
<p class="" style="">
But, when a device reports a field having multiple field types, the client should interpret this as the intersection of the corresponding field types, i.e. the corresponding
field has all corresponding field types. Example: A field marked as both a status value and as a historical value is in fact a historical status value.
</p>
<p class="" style="">
The following table lists the different field types specified in this document:
</p>
<div class="indent">
<p class="caption"><a name="table-4"></a>Table 4: Field Types</p>
<table border="1" cellpadding="3" cellspacing="0">
<tr class="body">
<th colspan="" rowspan="">Field Type</th>
<th colspan="" rowspan="">Description</th>
</tr>
<tr class="body">
<td colspan="" rowspan="">computed</td>
<td colspan="" rowspan="">A value that is computed instead of measured.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">historical*</td>
<td colspan="" rowspan="">A value stored in memory from a previous timestamp. The suffix is used to determine period, as shown below.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">historicalSecond</td>
<td colspan="" rowspan="">A value stored at a second shift (milliseconds = 0).</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">historicalMinute</td>
<td colspan="" rowspan="">A value stored at a minute shift (seconds=milliseconds=0). Are also second values.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">historicalHour</td>
<td colspan="" rowspan="">A value stored at a hour shift (minutes=seconds=milliseconds=0). Are also minute and second values.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">historicalDay</td>
<td colspan="" rowspan="">A value stored at a day shift (hours=minutes=seconds=milliseconds=0). Are also hour, minute and second values.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">historicalWeek</td>
<td colspan="" rowspan="">A value stored at a week shift (Monday, hours=minutes=seconds=milliseconds=0). Are also day, hour, minute and second values.</td>
</tr>
<tr class="body">
<td colspan="" rowspan="">historicalMonth</td>
<td colspan="" rowspan="">A value stored at a month shift (day=1, hours=minutes=seconds=milliseconds=0). Are also day, hour, minute and second values.</td>
</tr>