Object models for interoperability
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The document discusses an Internet of Things (IoT) toolkit that aims to enable interoperability between different machine-to-machine (M2M) protocols like MQTT, CoAP, and HTTP. It introduces a Smart Object API that provides a common interface to connect applications to devices using any M2M protocol. The API defines resources like descriptions, observable properties, agents, and observers to represent smart objects and handle events in a distributed manner.
Object models for interoperability
- 1. M2M Protocol Interoperability MQTT CoAP HTTP REST Bridge Using IoT Toolkit and the Smart Object API Michael J Koster [email protected]
- 2. IoT Toolkit Goals • Interoperability – Any ApplicaJon, any connected object, using any M2M protocol • Simple API arJculated through data models and high level informaJon models • PlaOorm-‐as-‐a-‐Service and gateway enabled • Open Source, IPR-‐free • Distributed, event-‐driven applicaJon soSware runs anywhere in the network • Web standard protocols and best pracJces
- 3. API IoT 1.0 – Things Connected to Apps M2M CoAP M2M MQ M2M XMPP M2M HTTP App API App API App API App • App runs on single service – Single Points Of Failure • Each app wriYen to a custom API • Diverse M2M is someJmes required but can inhibit interoperability • SoSware, User data, and Things are trapped in Silos • Difficult to connect new types of things and deploy new plaOorms • Very difficult to share resources or connect across plaOorms • Apps are not network-‐ effect enabled Connected Things, Sensors, Actuators, Data Sources
- 4. IoT 2.0 – Interoperability M2M CoAP M2M MQTT M2M XMPP M2M HTTP Smart Object API IoT Toolkit Discovery ApplicaJons Data Models • Object Model • REST + Event Model • M2M Abstrac9ons IoT Toolkit Connected Things, Sensors, Actuators, Data Sources Model Database • Easy to deploy new things and applicaJons using data models • Write once, run anywhere soSware • Any app to any thing via any M2M, use-‐ case appropriate M2M • Network effect enabled Machine Models
- 5. Graph-‐Structured, Event-‐Driven, Real Time Distributed ApplicaJons SO SO SO Gateways Server Cloud Endpoints • Sensors • Devices ApplicaJon Components And Resources Databases Registry -‐ Instances Repository -‐ Models Models • Discovery • Persistence • ReplicaJon • Resource Access • Data Models • Sensor Models • Machine Models • Templates HTTP MQTT CoAP XMPP HTTP CoAP MQTT Smart Objects
- 6. What Is The Smart Object API? • Virtual RepresentaJon of a physical Smart Object • Object Model – Web Object EncapsulaJon of properJes • REST API using JSON, XML, RDF, core-‐link-‐format representaJons • Data Models – Linked Data descripJons, Resource Discovery and Linkage • Event Model – Asynchronous M2M and applicaJon soSware event handlers
- 7. Object Model Web Object EncapsulaJon Smart Object Web protocol interfaces, also M2M e.g. MQTT, XMPP, … Event Model Links data with acJons Pub-‐Sub and event handlers Encapsulates local soSware components and handlers Self-‐describing data model For Resource Discovery and Linkage, RDF and core-‐ link-‐format Sensor or other data JSON, XML, data feeds
- 8. API – DescripJon (Data Model) • Contains graphs describing the resource data model • RDF triples in many popular representaJons – create (POST) loads a graph into the descripJon delete (DELETE) removes a graph or subgraph from the descripJon – set (PUT) updates a graph or subgraph – get (GET) returns a graph or subgraph • SemanJc Proxy for core-‐link-‐format compaJbility
- 9. API – Observable Property • Represents sensor data or a data feed • Can be JSON, xml, text, or other content type – create (POST): make new observable property – delete (DELETE) remove observable property – set (PUT) update ObservaJon Value or data feed – get (GET) returns the current ObservaJon Value • Formats for embedded Jme + locaJon data
- 10. API – Agent • Container for Event Handlers, soSware components invoked within the local context of a Smart Object • Observer class invokes Event Handler code in the Agent • Reference ImplementaJon – create (POST) make a new code object instance • handler or daemon – delete (DELETE) remove code instance – set (PUT) updates segng of a code instance – get (GET) returns segng of a code instance
- 11. API – Observers • Contains graphs which define the nodes and endpoints of event driven processing • Publish, Subscribe, and Event Handler paYerns • Reference ImplementaJon – create (POST) make a new Observer – set (PUT) update an Observer’s segngs – get (GET) return an Observer’s segngs – delete (DELETE) remove an Observer
- 12. Smart Object Structure – Object Model Smart Object DescripJon ObservableProperty ObservableProperty… Agent Publisher Subscriber Handler PropertyOfInterest DescripJon Observers Handler Instance Daemon Default Property
- 13. REST API • Python API – Local SoSware, Agents and Handlers – Resources (objects) are hierarchical properJes of other resources – self.indoorTempValue = sensors.weather.indoor_temp.get()! • Web API – HYp and CoAP REST Client access, MQTT topics – Resources are organized in hierarchical path – GET http:my_server:8000/sensors/weather/indoor_temp! – GET coap:my_server:5683/sensors/weather/indoor_temp! – MQTT subscribe my_server:1883 /sensors/weather/indoor_temp! • Default Property – Returns a resource associated with a higher level resource – GET of Smart Object returns it’s DescripJon; GET of Observable Property returns it’s ObservaJon Value
- 14. Protocol Bridge Examples • MQTT Endpoints and Bridge using Observer • CoAP Server Endpoint and link-‐data Proxy
- 15. MQTT Observer MQTT Broker REST Endpoint ObservableProperty mqYObserver PUT GET Publish from data producer Publish From REST API Publish to Other Subscribers SUB Publish to REST API Connects REST Resource to MQTT Topic Publish and Subscribe
- 16. MQTT Observer MQTT Broker REST Endpoint ObservableProperty mqYObserver PUT GET Publish from data producer Publish From REST API Publish to Other Subscribers SUB Publish to REST API Publisher Publishes REST Resource updates to the broker
- 17. MQTT Observer MQTT Broker REST Endpoint ObservableProperty mqYObserver PUT GET Publish from data producer Publish From REST API Publish to Other Subscribers SUB Publish to REST API Subscriber Makes last published data available at the REST endpoint
- 18. MQTT Observer MQTT Broker REST Endpoint ObservableProperty mqYObserver PUT GET Publish from data producer Publish From REST API Publish to Other Subscribers SUB Publish to REST API Pub+Sub Repeats data updates in both direcJons
- 19. MQTT Bridge to mulJple REST endpoints MQTT Broker REST Endpoint ObservableProperty mqYObserver PUT GET Publish from data producer Publish to Other Subscribers REST Endpoint ObservableProperty mqYObserver PUT GET
- 20. CoAP Server Endpoint Smart Object JSON JSON JSON RDF SemanJc Proxy RDF link-‐format • CompaJble Object Models • Observer paYern • Standard JSON Resources • SemanJc Proxy exposes stored RDF via core-‐link-‐format GET/POST operaJons
- 21. IoT Toolkit Protocol Interoperability CoAP MQTT MQTT HTTP smartobjectservice.com ec2-‐54-‐200-‐106-‐25.us-‐ west-‐2.compute.amazonaws.com
- 22. IoT Toolkit • IoT Toolkit is a reference implementaJon of the Smart Object API and related tools • REST API with real-‐Jme event model for the Internet of Things • Lightweight server that can run on small computers e.g. Raspberry Pi, ARM/Linux PC, AWS t1.micro • M2M using HTTP, MQTT, and CoAP, others
- 23. IoT Toolkit Project Status • Smart Object API is complete and stable • IoT Toolkit Demo • M2M interoperability: MQTT, CoAP, HTTP interfaces • Development Roadmap Examples – Harden code, excepJon handling, API Tests – Scalable server, mulJ-‐tenancy, persistence models – Graph-‐based resource access control – Data model API for resource discovery and linkage – XMPP endpoint and proxy for XEP-‐0060, XEP-‐0323, XEP-‐0325 – Programming model UI e.g. Node Red – Web UI for debug and demo, applicaJons • Navigator, Dashboard, AnalyJcs, Graphs and Charts