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FI-WARE NGSI OverviewJuanjo HierroTelefonica Digital, Coordinator and Chief Architect, FI-WAREjhierro@tid.es, @JuanjoHierro

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Index

Basic concepts

APIs

NGSI in the FI-WARE Architecture

010203

01Basic concepts

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, …)

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Context Broker

Applications

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 (<name, type, value> triplets)

• Optional meta-data linked to attributes (also <name, type, value> 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

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Meta-data

• Name• Type• Value

Context Element attributes

• Name• Type• Value

Context Element

• EntityId• EntityTyp

e 1 n 1 n

“has” “has”

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

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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)

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02APIs

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

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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

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Context Consumer

queryContext

Context Producer Context (Publish/Subscribe)Broker

updateContext

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

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Application

registerContext (producer URI, registration data, duration, registration_id)

Context Provider Context (Publish/Subscribe) Broker

queryContext

Context Consumer

queryContext

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

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Application

subscription_id = subscribeContext (consumer, expr, duration)

Context ConsumerContext (Publish/Subscribe) Broker

notifyContext (subscription_id, data/context)

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.

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Context Broker Federation (1)

A Context Broker may be subscribed as Context Consumer on another Context Broker

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Application

subscr_id_1 = subscribeContext (consumer1, expr1, duration1)

Context Consumer 1Context 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

Context Broker Federation (2)

A Context Broker may be subscribed as Context Producer on another Context Broker

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Application

subscription_id_1 = subscribe (consumer1, expr1, duration1)

Context Broker 2

notifyContext

Context Producerquery

queryContext

Application

registerContext (Context Broker GE 2, what, duration2)

Context Broker 1

updateContext

queryContext

Context Consumer 2

Context Consumer 1

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

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Context Broker GE

ContextProducers

ContextConsumers

Producers port

subscription ports

subscriptions

update

query

notify

notify

update

query

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

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Application 2

discoverContext

Application 1 Context (Publish/Subscribe)Broker

registerContext

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

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application1

subscription_id = subscribeContextAvailability (application2, expr, duration)

application2Context Broker

notifyContextAvailability (subscription_id, updates)

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

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03NGSI in the FI-WARE Architecture

FI-WARE Context/Data Management Platform

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Context/Data Management Platform

Applications

OMA NGSI-9/10Processing/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/an

alysis

Data generated either by CEP or

BigData is published

Gathered data injected for CEP-like

processing Direct bigdata injection

Programming of rules

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

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 GEsGateway/

Device Platform GEs

Gateway/Device

Platform GEs

Native NGSI IoT

Agent

Native NGSI IoT

Agent

Thanks !!

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