Link Kit SDK is provided by Alibaba Cloud for device manufacturers to connect devices to Alibaba Cloud IoT Platform, then the devices can be managed by Alibaba Cloud IoT Platform. Link Kit SDK can connect to Alibaba Cloud IoT platform through MQTT/CoAP/HTTP/HTTPS, so devices must support the TCP/IP protocol stack to make Link Kit SDK work properly; For Non-IP devices, such as Zigbee and KNX devices, they can be connected to Alibaba Cloud IoT platform throught a gateway that has already integrated with Link Kit SDK.
Alibaba Cloud builds several industry solutions/services on top of Alibaba Cloud IoT Platform, such as Smart life/Smart manufacturing/and Smart City, these solutions/services provide more functions in addition to the device management provided by Alibaba Cloud IoT platform. This means Alibaba Cloud does not provide different device SDKs for different industry solutions/services, The relationship among the Alibaba Cloud IoT Platform, the industry solutions/services, and the Link Kit SDK is as follows:
The software architecture and functions of the Link Kit SDK are as follows:
Application programming interface (API)
The Link Kit SDK provides APIs for the device to control various function modules
The Link Kit SDK provides a series of function modules:
- Cloud Connection: provides a variety of methods to connect a device to the Alibaba Cloud IoT Platform, such as MQTT, CoAP, HTTP, and HTTPS.
- Device Authentication: verifies if a device connected to the IoT platform is legal, the authentication can be based per-device level or per-product level.
- OTA: supports device firmware upgrades.
- Sub-device management: connects sub-devices that connected by a gateway to the IoT Platform.
- Wi-Fi Provisioning: transmits the Wi-Fi AP SSID and password to an IoT device that uses Wi-Fi as the uplink network interface.
- Device Modelling: device management based on device properties, services, and events.
- User binding: provides a secure binding token which will be used by SmartLife to bind a user’s account with the device.
- Local device control: if a device connects to the same local area network (LAN) as your smart phone or a gateway, it can be controlled by the smart phone or the gateway directly through this function. This allows faster and more reliable device control.
Hardware abstraction layer (HAL)
SDK is designed to be independent from OS and products, so it defines a layer(HAL) for this purpose, device manufacturers need to implement these functions.
The Link Kit SDK is suitable for all products that can communicate with the Alibaba Cloud IoT Platform through TCP/IP. Some typical kinds of devices are as follows:
Most of these devices use Wi-Fi to connect to the wireless router at home, and then connect to the Internet. These home devices include: smart doorbells, locks, fans, cleaning robots, air conditioners, refrigerators, extension blocks, air purifiers, heaters, curtains, lamps, electric water heaters, range hoods, microwave ovens, ovens, etc. The network access diagram for these products is as follows:
1. Devices that use Ethernet to connect to the wireless router can also integrate with Link Kit SDK to connect to the Alibaba Cloud IoT Platform.
Gateway products & Sub-Device products
Gateways usually connect to the internet via an Ethernet interface, it supports TCP/IP stack so it can integrate Link Kit SDK.
Devices that do not support the TCP/IP stack, needn’t integrate the Link Kit SDK. Instead, these devices can connecte to Alibaba Cloud IoT Platform via a gateway which has already integrated with the Link Kit SDK. The network protocol between these kinds of devices and a gateway can be Zigbee, Bluetooth, 433, KNX, etc. The network access diagram for these Sub-Device products is as follows:
Products that use cellular network connections
IoT products that use the cellular network connections of telecom operators are mostly used in rural and urban scenarios with high cellular network coverage, or in mobile scenarios. These products include logistics transportation vehicles, vending machines, meteorological data acquisition systems, hydrological data acquisition systems, smart electric meters, and smart water meters. The network access diagram for these products is as follows: