Terminology¶
This section introduces the major concepts for EnOS IoT Hub.
Model¶
A model is the abstraction of the features of an object that is connected to the IoT. The model defines the features of the object’s attributes, measure points, services, and events.
For more information, see Model. A model can be associated to multiple products.
Product¶
A product is a collection of devices with the same features. The product enables you to manage a collection of devices that are derived from the same model but differ in terms of deployment.
Based on the model, a product further defines the communication specifications for the device to connect to the IoT, such as the secure authentication mechanism and data format. For example, collection A and collection B might be deployed in different network environments, and therefore requires the device telemetry to be transmitted in different formats. Different formats require different bandwidths, for example, binary data can save up to 75% bandwidth compared to JSON.
Device¶
A device is the instance of a product. A device is created from a product so that it inherits not only the features defined by the model, but also the communication features, for example, the device key-secret pair and device certificate used for secure communication. For more information, see Devices in EnOS.
Asset¶
An asset is the instance of a model. An asset is created from a model so that it inherits features defined by the model.
An asset can be:
- A single device, such as an inverter.
- A group of devices, such as a wind farm. The model of a wind farm might, for example, define two measurement points: the overall active power and cumulative power generation of the site. However the data of the 2 measurement points are not obtained directly like how it is done for single devices, but calculated using the aggregation of all devices in the site. In this case, the site does not need to have the device key-secret pair for site-level connection.
A device is an asset, but an asset is not necessarily a device. For more information, see Asset Tree.
MQTT Message Size(Bytes)¶
EnOS supports devices to access EnOS based on the MQTT protocol. Users can also send data to devices based on the MQTT protocol to control the devices via EnOS Device Connectivity and Management.
EnOS Device Connectivity and Management will count the amount of messages sent from the devices and EnOS, and display them in Device Management > Overview.
Message Size from Devices¶
The amount of messages(bytes) sent from the devices and the servers to EnOS in a specified time period.
Message Size from EnOS¶
The amount of messages(bytes) sent from the EnOS to the devices and the servers in a specified time period.
MQTT Message(Count)¶
The MQTT message size(bytes) will be converted into the number of messages with the standard of 512 bytes per message and be displayed in Device Management > Overview.
Message from Devices¶
The number of messages(count) sent from the devices and the servers to EnOS in a specified time period.
Message from EnOS¶
The number of messages(count) sent from the EnOS to the devices and the servers in a specified time period.
Device Authentication¶
In order to ensure the security of the connection, the devices need to be authenticated before connecting to EnOS. EnOS supports the following two authentication methods:
- Secret-based one-way authentication: the devices use the device triple information to authenticate and EnOS verifies whether the devices are authentic.
- Certificate-based two-way authentication: the devices use a certificate to authenticate. EnOS verifies whether the devices are trustworthy based on the certificate, and the devices verifies whether the cloud is trustworthy based on the certificate.
Secret-based One-way Authentication¶
The device triple information that can be obtained when creating products and registering devices is used for authentication. For more information about device triple information, see Device Triple Information.
Secret-based one-way authentication can be divided into the following two ways:
- Static Authentication: the device can use the device triple information to authenticate after the triple is burned into the device. If it passes, the connection is complete.
- Dynamic Authentication: the device use the product key, product secret, and device key to authenticate. If it passes, the device secret will be returned from EnOS. After that, the device can use the triple information to authenticate.
Certificate-based Two-way Authentication¶
To enable certificate-based authentication, log in to the EnOS Management Console, go to Device Management > Products > Product Details, and enable Certificate-Based Authentication.
For more information about certificate-based authentication, see Device Security Schemes.
Device Triple Information¶
In order to ensure the security of the connection, the devices need to be authenticated before connecting to EnOS. EnOS supports the following two authentication methods:
- Secret-based one-way authentication
- Certificate-based two-way authentication
If the devices need the secret-based authentication, the following keys and secrets is required:
- Product key & product secret: you can view the product key and product secret after creating the product in EnOS Management Console > Device Management > Products. For more information, see Managing Products.
- Device key & device secret: you can view the device key and device secret after creating the device in EnOS Management Console > Device Management > Device Assets. For more information, see Retrieving the Device Triple Information.
Device triple information includes the product key, device key, and device secret. For how to use the triple information to authenticate, see Device Authentication.