This topic describes the terms that you need to understand about IoT Platform.
Terms
Term | Description |
product | A product is a set of devices with the same features. IoT Platform issues a unique ProductKey for each product. |
device | A device belongs to a product. IoT Platform issues a unique DeviceName for each device of the same product. Devices can directly connect to IoT Platform, or be attached as sub-devices to a gateway that is connected to IoT Platform. |
group | IoT Platform allows you to create device groups. Each device group can contain devices of different products. You can use device groups to manage devices across products. |
gateway | A gateway can directly connect to IoT Platform and allows you to manage sub-devices. Sub-devices can communicate with IoT Platform only by using a gateway. |
sub-device | A sub-device is essentially a device. Sub-devices cannot directly connect to IoT Platform and must be attached to a gateway. |
device certificate | A device certificate consists of a ProductKey, a DeviceName, and a DeviceSecret.
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ProductSecret | A ProductSecret is the private key issued by IoT Platform for each product. A ProductSecret is usually used in pair with a ProductKey for unique-certificate-per-product authentication. ProductSecrets are required in device authentication and communication. Make sure to record this value for reference. |
topic | A topic is a UTF-8 character string that is used as a transmission medium during publish/subscribe communication. A device can publish messages to a topic or subscribe to messages from a topic. |
topic category | A topic category is a set of topics that are associated with different devices under the same product. ${productKey} and ${deviceName} are used to specify a unique device. A topic category is applicable to all devices under the same product. |
publish | The allowed operation of a topic. If the Allowed Operation parameter of a topic is set to Publish, you can publish messages to the topic. |
subscribe | The allowed operation of a topic. If the Allowed Operation parameter of a topic is set to Subscribe, you can subscribe to messages from the topic. |
RRPC | RRPC is short for revert-RPC. A remote procedure call (RPC) uses the client/server mode, and allows you to request a remote service without understanding the underlying protocol. An RRPC allows you to send a request from the server to a device and receive a response from the device. |
tag | You can add tags to products, devices, and groups.
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Alink protocol | The Alink protocol is used for communication between devices and IoT Platform. |
TSL model | IoT Platform uses Thing Specification Language (TSL) to describe device features. A TSL model defines the device properties, services, and events. TSL models use the JSON format. You can organize data based on a TSL model and submit the data to IoT Platform. |
property | A property is a TSL feature that describes the status of a device, such as the temperature information that is collected by an environmental monitoring device. Properties support the GET and SET request methods. Applications can send requests to retrieve and set properties. |
desired property value | IoT Platform allows you to set desired property values for a device. If the device is online, the property values on the device are updated in real time. If the device is offline, the desired property values are cached in IoT Platform. After a device goes online, the device obtains the desired property values and updates its property values. |
service | A service is a TSL feature that describes a capability or method of a device. The capabilities or methods can be used by external requesters. You can specify the input and output parameters of a service. Compared with properties, services can be called by using a command to implement complex business logic. For example, you can call a service to perform a specific task. |
event | An event is a TSL feature that describes a runtime event of a device. An event contains a notification that requires action or attention. An event may contain multiple output parameters. Some example events include notifications for task completions, device failures, and temperature alerts. You can subscribe to or push events. |
data parsing script | If devices use pass-through or custom-formatted data, you must write data parsing scripts in IoT Platform to parse the data. You must convert the binary data or custom JSON data that is submitted by the devices to the Alink JSON data that is supported by IoT Platform. You must also convert the Alink JSON data that is sent by IoT Platform to the custom-formatted data that is supported by the devices. |
device shadow | A device shadow is a JSON file that is used to store the status information of a device or an application. Each device has a unique device shadow in IoT Platform. Device shadows allow you to obtain and set the status of devices by using the MQTT or HTTP protocol regardless of whether the devices are connected to the Internet. |
rules engine | You can create and configure rules in IoT Platform to implement the following features: server-side subscription, data forwarding, and scene orchestration. |
server-side subscription | Your business server can subscribe to messages of a product in IoT Platform. The following types of messages can be subscribed to: upstream device messages, notifications of device status changes, notifications indicating that a gateway discovers new sub-devices, notifications of device lifecycle changes, and notifications of device topology changes. Server-side subscription supports the following two methods:
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data forwarding | You can use the data forwarding feature to forward data from a topic to another topic or another Alibaba Cloud service for storage or processing. |
scene orchestration | You can use the scene orchestration feature to develop automated business logic in a visualized manner. You can define interaction rules between devices and deploy the rules in IoT Platform or edge instances. |
unique-certificate-per-device authentication | A device certificate is burned to each device. The device certificate consists of a ProductKey, a DeviceName, and a DeviceSecret. When you connect a device to IoT Platform, IoT Platform verifies the device based on the certificate. |
unique-certificate-per-product authentication | A product certificate is burned to all devices under the same product. A product certificate consists of a ProductKey and a ProductSecret. When a device sends an activation request, IoT Platform authenticates the device based on the product certificate. If the authentication succeeds, IoT Platform issues a device certificate to the device. Then, the device uses the certificate to connect to IoT Platform. |
instance | You can manage resources such as products, devices, and rules in IoT Platform instances. The following types of instances are supported:
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