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http://www.fi-ppp.eu http://www.fi-ware.eu FI-WARE NGSI Overview Juanjo Hierro Telefonica Digital, Coordinator and Chief Architect, FI-WARE jhierro@tid.es, @JuanjoHierro jhierro@tid.es 1
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Index Basic concepts APIs NGSI in the FI-WARE Architecture 01 02 03
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01 Basic concepts
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Context OMA NGSI Context Management is about management of Context data (aka Context Information) Context Information is always relevant to “entities”, although entities can be anything (applications, users, things, …) 4 Context Broker Applications
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Context Elements (1/2) Context Information in OMA NGSI is represented through data structures called context elements which have associated: An EntityId and EntityType, uniquely identifying the entity to which context data refers. A sequence of one or more data element attributes ( triplets) Optional meta-data linked to attributes (also triplets) As an example, we may consider the context element reporting info on: attributes “speed”, “geolocation”, “current established route” of a “car”, or attributes “last message geolocation”, “last message contents” of an “user” The EntityId is a string, and can be used to designate “anything”, not necessarely “things” in the “real world” but also application entities 5 Meta-data Name Type Value Context Element attributes Name Type Value Context Element EntityId EntityType 1n1n “has”
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Context Elements (2/2) There may be as many kinds of Context Elements as combinations of attributes linked to an entity: Typically a context element is generated whenever an query (update) on values of a list of attributes linked to an entity is requested (occurs) Only queried/updated attributes are communicated, so the amount of information that is transmitted is minimized Example: Cars may have attributes “brand”, “model”, “license plate”, “established route”, “geo- location”, “current speed”, “gas level” The first time existence of the car is recorded, a context element bringing values of attributes “brand”, “model”, “license plate” is generated Any time a route is established using the cars’ navigator, a context element bringing updated values of “established route”, “gas level” and “geo-location” is generated whenever a route is established A context element bringing updated values of “geo-location”, “current speed” and “gas level” is generated every x minutes Occurrences of context elements are referred as “events” in FI-WARE 6
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Conceptual model: advantages Not linked to a particular data/context representation formalism: Neither for transferring Nor storing Can work with a standard IoT formats (SensorML) but at the same time allows to overcome the limitations derived from the adoption of a single standard format The flexible nature of data structures linked to context elements enable an optimized communication (only information about queried or updated attributes is transferred) 7
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02 APIs
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OMA NGSI and FI-WARE APIs NGSI Context Management specs have been published by OMA but FI-WARE will not stick to what has been published: Ready to change whatever makes the API more usable and useful Ready to incorporate extensions to make the API more powerful yet simple Ready to fast-track incorporated changes in OMA That’s why we distinguish between “OMA NGSI” and “FI-WARE NGSI” We may consider potential extensions dealing with stream-based communication in the future, for example 9
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Basic entities and operations (1) Context Producers publish data/context elements by invoking the updateContext operation on a Context (Publish/Subscribe) Broker. Context data is kept persistent by Context Brokers and ready to be queried while not exceeding a given expiration time. This is a distinguishing feature of the OMA Context Management model as compared to some Event Brokering standards. You can think in the Context Broker as a kind of virtual Repository/DB where producers insert context information and consumers query for it Context Consumers can retrieve data/context elements by invoking the queryContext operation on a Context Broker 10 Context Consumer queryContext Context ProducerContext (Publish/Subscribe) Broker updateContext
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Basic entities and operations (2) Some Context Producers may also export a queryContext operation Context Brokers may invoke at any given time to query on values of a designated set of attributes linked to a given set of entities. They are called Context Providers. Because Context Providers exporting the queryContext operation are typically unknown “a priori”, Context Brokers export a registerContext operation which enable to register what Context Producers may be queried Note that the Application which subscribes a particular Context Producer may or may not be the/a Context Producer itself 11 Application registerContext (producer URI, registration data, duration, registration_id) Context ProviderContext (Publish/Subscribe) Broker queryContext Context Consumer queryContext
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Basic entities and operations (3) Some Context Consumers can be subscribed to reception of data/context elements which comply with certain conditions, using the subscribeContext operation a ContextBroker exports. Such subscriptions may have a duration. Subscribed consumers spontaneously receive data/context elements compliant with that subscription through the notifyContext operation they export Note that the Application which subscribes a particular Context Consumer may or may not be the/a Context Consumer itself 12 Application subscription_id = subscribeContext (consumer, expr, duration) Context ConsumerContext (Publish/Subscribe) Broker notifyContext (subscription_id, data/context)
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About queries, registrations and subscriptions Queries, registrations and subscriptions requests are formulated on: List of entity ids (these ids may include patters) List of attributes or “attribute domains” (identifiers used to denote a group of related attributes) Besides, queries and subscriptions requests can be formulated so that certain restrictions, established as conditions upon values of given attributes or metadata, have to be met. 13
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Context Broker Federation (1) A Context Broker may be subscribed as Context Consumer on another Context Broker 14 Application subscr_id_1 = subscribeContext (consumer1, expr1, duration1) Context Consumer 1 Context Broker 2 notifyContext Context Producer Context Consumer 2 query notifyContext Application subscr_id_2 = subscribeContext (Context Broker GE 2, expr2, duration2) Context Broker 1 updateContext queryContext
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Context Broker Federation (2) A Context Broker may be subscribed as Context Producer on another Context Broker 15 Application subscription_id_1 = subscribe (consumer1, expr1, duration1) Context Broker 2 notifyContext Context Producer query queryContext Application registerContext (Context Broker GE 2, what, duration2) Context Broker 1 updateContext queryContext Context Consumer 2 Context Consumer 1
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Handling multiple subscriptions A single Context Broker GE may handle several subscriptions A Context Consumer may be subscribed through more than one subscription A Context Consumer may consume events through subscriptions or making explicit queries 16 Context Broker GE Context Producers Context Consumers Producers port subscription ports subscriptions update query notify update query
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Extended operations (1) Context Brokers export the discoverContext operation enabling applications to discover entities or even attributes and attribute domains that have been registered in the system 17 Application 2 discoverContext Application 1Context (Publish/Subscribe) Broker registerContext
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Extended operations (2) Some applications can be subscribed to registration of entities or availability of attributes and attribute domains which comply with certain conditions, using the subscribeContextAvailability operation a ContextBroker may export. Such subscriptions may have a duration. Subscribed applications spontaneously receive updates on new entities, attributes or attribute domains compliant with that subscription through the notifyContextAvailability operation they export Note that the subscriber and subscribed applications may not be the same 18 application1 subscription_id = subscribeContextAvailability (application2, expr, duration) application2Context Broker notifyContextAvailability (subscription_id, updates)
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Some hints about OMA NGSI specs Operations are grouped into two major interfaces (not clear why NGSI-10 › updateContext › queryContext › subscribeContext / unsubscribeContext / updateContextSubscription › notifyContext NGSI-9 › registerContext › discoverContextAvailability › subscribeContextAvailability / unsubscribeContextAvailability / updateContextAvailabilitySubscription › notifyContextAvailability 19
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03 NGSI in the FI-WARE Architecture
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FI-WARE Context/Data Management Platform 21 Context/Data Management Platform Applications OMA NGSI-9/10 Processing/Analysis Algorithms Gathered data is injected for processing/analysis Distributed Context Sources Complex Event Processing - CEP (PROTON) BigData Analysis/Processing (COSMOS) Context Broker (Orion/CAP) Processed data is injected for processing/ana lysis Data generated either by CEP or BigData is published Gathered data injected for CEP-like processing Direct bigdata injection Programming of rules
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FI-WARE IoT-M2M & Context/Management altogether NGSI IoT Adapter Backend Device Management (IDAS DCA) Backend Applications FI-WARE NGSI-9/10 (entities: things) (entities: things, other) FI-WARE NGSI-9/10 Things Management Device-level Management API Context Broker (Orion/CAP) IoT-enabled Context Management Backend BigData Analysis (COSMOS) CEP (PROTON) Other sources FI-WARE NGSI-9/10 Gateway/Device Platform GEs Direct connection for higher performance Gateway/Device Platform GEs
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FI-WARE IoT-M2M & Context/Management altogether NGSI IoT Adapter Backend Device Management (IDAS DCA) Backend Applications FI-WARE NGSI-9/10 (entities: things) (entities: things, other) FI-WARE NGSI-9/10 Things Management Device-level Management API Context Broker (Orion/CAP) IoT-enabled Context Management Backend BigData Analysis (COSMOS) CEP (PROTON) Other sources FI-WARE NGSI-9/10 Gateway/Device Platform GEs Direct connection for higher performance Gateway/Device Platform GEs Native NGSI IoT Agent
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Thanks !! 24 http://www.fi-ware.eu
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