Core Concepts and Functionality

Orion Context Broker operates based on entities, attributes, and subscriptions. These elements enable interaction between context producers and consumers.

Entities

Entities represent objects in the system and have properties called attributes. For example, a sensor monitoring room temperature can be an entity, and the temperature reading is its attribute.

Each entity is identified by:

  • ID: Unique identifier for the entity.

  • Type: Defines what kind of object the entity represents (e.g., "Sensor", "Room").

Attributes

Attributes are key-value pairs that describe the state or properties of an entity. For example:

  • temperature: 25°C

  • humidity: 60%

Attributes can be updated over time, reflecting changes in the context information.

Subscriptions

A subscription is a mechanism that allows applications to receive notifications when certain conditions are met, such as an attribute change or a threshold being reached.