On a Device Information Model for devices in oneM2M

Joerg Swetina, NEC Laboratories Europe

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DeviceInformation Model

DeviceInformation Model

Area NW

Area NW

CSE

AE

How are devices treated in oneM2M ?

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CSE

Mca

IPE(Application)

IPE … Inter-working Proxy Application Entity

CSE

AEMcc

CSE

AEMcc

oneM2M Devices

legacy (non-oneM2M) Devices and [non-IP] Area Networks

▐ Every type of devices has its own Device Information Model…

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CSE

Who contributes to the Device Information Model

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Domain specific

Manufacturer

AE

Contextspecific

Manufacturer defines(at least) Syntactic Device modelInput- Output operationsEnables creation of (oneM2M)representations - resourcessyntactic interoperabilityManufacture specific data

Domain stakeholder (e.g. HGI) defines domain specific Semantic Device modelGeneric naming of device typesoperation types … Abstract devicessemantic interoperability

Cross-domain stakeholders may define context specific extensionsLocation informationRelationships to thingsUsage for Virtual DevicesEnables linking device types tothe context they are used in

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Some facts about device types (not only IP capable ones !!)

Note, this is about types of devices, not individual instances !

▐A device always containsEither only a receiver (e.g. a remote controlled power plug – only

supports Input operations, no ACK possible!) or only a sender (e.g. a humidity sensor that periodically reports

measurements – only supports Output operations) or both (e.g. an IP connected device)

• Input- and output operations may be correlated - by the used transport protocol - to each other (e.g. a Response is linked to a specific Request)

▐A physical device has some sensor- and/or actuator hardware that interact with the physical world.Abstract / virtual devices do not necessarily have such hardware.

▐A physical device contains hardware modules that manage the communication of the device via some M2M Area Network.

The device has an address within the Area Network. The addressing scheme is determined by the type of the Area Network

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Some facts about device types (II)

▐ A physical device contains hardware that can be described in terms of its physical properties (e.g. Battery capacity, Allowed operating temperature range …). These properties can beStatic (e.g. Allowed operating temperature range) orDynamic (e.g. current load level of the battery)

▐ A device (physical or abstract/virtual) has properties related to its operation, e.g.A set of states that any instance of that device is in.

▐ A device (physical or abstract/virtual) has some none-physical properties - ‘meta-information’, e.g.Name/Identifier of manufacturerModel identifier, Universal Product Code, Serial number ...

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Device Information Model (Also called Device Capability)

and “Device Model Template”

▐ “Device Information Model” contains: The information on a device type as indicated above can formally be described (e.g. as XML document) in an information model of that device type.Must at least contain all input- and output- operations of a device type

but can contain more information. Is system- (protocol/hardware/software) independentCan be de used to create system specific representations

(e.g. oneM2M resources)

▐ A “Device Model Template” would be the schema (e.g. specified as a XSD document) that specifies what parameters constitute the information model of (any) device. “Device Model Template” needs to be a collaborative work of multiple SDOs Is manufacturer (and protocol- and hardware/software) independentShould allow to be extensible but it should contain sufficiently many

parameters to be able to describe most device types without extension.

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Extension with semantic information

by Domain- and Cross- domain

stakeholder

Putting the picture together

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TheThe Device Template Device Template

DeviceInformation Model:

Device Type ADevice

Information Model:Device Type B

(Manufacturer YY)Device

Information Model:Device Type C(Manufacturer

ZZ)

The Device Template is created through

collaboration among SDOs

Manufacturers create Device

Information Models

Representationsin target systems(defined through

e.g. a Interworking Proxy Application

Entity - IPE)

Instances(individual

devices in a specific system)

oneM2Mrepresentation

of Device Type C

ZigBeerepresentation

of Device Type C

Instance 1Instance 2

Instance 3Device Information Model can be extended by Domain- and Cross- domain stakeholder

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Information Model contains Input- Output operations of a device▐ Example of a

washing machine – I/O operations consist of 3 kinds of data: Names I/O data types Communication

pattern

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Input operation type 1•Name: Start / Pause•I/O type: binary•communication pattern:Instruction (unacknowledged)

Input operation type 2•Name: Spin Selection•I/O type: no-type•communication pattern:Instruction (acknowledged)

Input operation type 3•Name: Function Selector•I/O type: complex type:

• Selection “OFF”• Selection “COTTONS”

• Select integer from: min-value = 30 max-value = 90min-step = 10

• Selection “SPECIALS”• …

Output operation type 1•Name: Spin speed display•I/O type: selection 1 out of “OFF”, “MED”, “MAX”•communication pattern:Notification (response to Input operation type 2)

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Input- Output operations (II)

▐ I/O data types: I/O data types are data types (like boolean, integer, ... or more

complex structures) together with their restrictions (e.g. maximum/minimum values, stepsize …) and describe:

• For input: all acceptable input values for the device

• For output: all possible output values

I/O data types correspond to Datatypes in XML Schema of W3C

▐ NamesGive names to operation types to make them distinguishableGive names to parameters. e.g in a “SELECTION”

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Input- Output operations (III)

▐ communication patterns:Describe the direction of data-flow (Input or Output)Can be:

• Notification (device asynchronously transmits data to the device’s peer)– pushing data device => peer e.g. periodic reporting of humidity.

Is also possible when device has only “sender” functionality

• Instruction (peer entity issues a request, carrying the data, to the device )– pushing data device <= peer e.g. a remote controlled power switch.

Is also possible when device has only “receiver” functionality– Can be acknowledged by the device through a correlated - immediate or

separate - “Notification” if device has also “sender” function

Input- Output operations allow syntactically correct, yet application independent communication with a device, => syntactic interoperability !

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Semantics added to the Information model

▐ Semantics provide additional parameters of the device type as well as meta-information.

▐ Semantics are not needed for syntactic interoperability.Examples:

• Semantic information provided my manufacturer:– Manufacturer is “Candy”– Model is “GOF462S”– The address type is “WiFi” (can be accessed through a WiFi Area NW)– Input operation “Start / Pause” does the following:

When setting binary state “TRUE” this starts the washing process according to the current state of all other input operation variables.

• Semantic information provided by Domain stakeholder– The generic name of this device type is “Washing Machine”

• Semantic information provided by Cross-Domain stakeholder(e.g. home management system)

– A device of type “Washing Machine” may have a relationship “is_located” with a thing of type “Room”

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Proposal for way forward in oneM2M

▐ Elaborate and agree on the oneM2M view (responsibilities ...) on Device Information ModelManufacturer, Domain stakeholder, Cross-Domain stakeholder

▐ Check what parameters, from oneM2M point of view, must to be contained in the Device Information Model

(required for syntactic interoperability)should additionally be contained in the Device Information Model

(semantic information for semantic interoperability and for describing context)

▐ Create an example (toy Device Information Model) and show the mapping into oneM2M resources

Send all of that to other SDOs such that these SDOs can create the Device Template.

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