1. ARC
Proposed design principles for modelling services, datapoints and operations
Group Name: ARC
Source: Joerg Swetina, NEC
Meeting Date:
Agenda Item: TBD

2. Backgroud
Independent of the question whether devices are native oneM2M devices or interworked devices, services, datapoints and operations are needed to communicate with the device's applications:
In the case of native oneM2M devices (ASN, ADN) a communicating entity communicates with a oneM2M AE of the device
In the interworked case a communicating entity communicates with the oneM2M IPE-AE that translates and proxies the communication with the AE on the device

3. Terminology (I) Datapoint: Operation:
Stateless communication according to REST principles
The AE (native AE or IPE) or the communicating entity communicates by reading from- or writing to a Datapoint
Datapoints can be simple (integer, bool) or can be structured (lists, named sub-structures)
Operation:
Communication that requires to keep a state till the communication has ended
The AE or the communicating entity sends data and expects an answer back
Multiple, independent data need to be sent at the same time
SDT (TS-0023) calls an Operation: Action / Event

4. Terminology (II) Service: Application Entity (AE): Device:
Groups Datapoints and Operations that belong together
Different Services can have the same Datapoints and Operations
SDT calls a Service: Module or ModuleClass
Application Entity (AE):
Indididually addressable entity in the network that exposes Services
Device:
Physical thing that can communicate electronically
A Device has 1..n AEs

5. Representation: oneM2M resources
AE / device
CSEBase
<AE> or <flexContainer>
Service
Datapoint
Datapoint
(customAttributes)
<flexCont>
Datapoint
Copy
Operation (SDT: Action, Event)
InputData
<flexCont>
InputData
OperationResult - if operation has output (currently not in SDT)
InputData
InputData
<flexCont>
OutputData
OutputData

6. Communication principle (I)
Creation of resources
Communicating entity subscribes to <AE> of AE (e.g. IPE) it wants to communicate with.
AE (e.g. IPE) creates <flexContainer>s for Services and Operations and subscribes to them
Communicating entity subscribes to newly created <flexContainer>s.

7. Communication principle (II)
Sending data CE => AE using DataPoints
Communicating entity UPDATEs the Service <flexContainer> with a changed Datapoint = customAttribute of Service <flexContainer>.
AE (e.g. IPE) gets NOTIFYed about the changed customAttribute
Sending data AE => CE using DataPoints
AE UPDATEs Service <flexContainer> with a changed Datapoint = customAttribute.
CE gets NOTIFYed about the changed customAttribute

8. Communication principle (III)
Sending data CE => AE using Operations
Communicating entity UPDATEs an Operation <flexContainer> with InputData (= customAttributes of Operation <flexContainer>).
AE (e.g. IPE) gets NOTIFYed about the updated Operation <flexContainer> == If no OutputData are created the flow stops here == otherwise, if OutputData are created:
AE computes OutputData.
AE CREATEs OperationResult <flexContainer> as child of Operation <flexContainer>
InputData are copied into OperationResult <flexContainer>
OutputData are added as customAttributes
CE gets NOTIFYed about creation of OperationResult <flexContainer> and retrieves OutputData
Sending data AE => CE using Operations works analogous