IoT protocols refer to protocols used for communication and data transmission between devices in the IoT environment. According to different functions, IoT protocols can be divided into transmission protocols , communication protocols and industry protocols .
Transmission protocol: Generally responsible for networking and communication between devices within a subnet. For example, Wi-Fi, Ethernet, NFC, Zigbee, Bluetooth, GPRS, 3G/4G/5G, etc. These protocols ensure the security and reliability of data transmitted over the network.
Communication protocol: It is mainly a device communication protocol that runs on the traditional Internet TCP/IP protocol and is responsible for data exchange and communication between devices through the Internet. For example, MQTT, CoAP, HTTP, etc.
Industry agreement: A unified standard agreement within an industry. For example, Internet of Vehicles JT/T808, Video GB/T 28181, etc.
01
Transfer Protocol
| protocol | Protocol description and application scenarios |
| Modbus | Protocol description: Modbus protocol is an application layer message transmission protocol, including three message types: ASCII, RTU, and TCP. Through this protocol, controllers can communicate with each other, with controllers and other devices via a network (such as Ethernet). Application scenario: widely used in industrial fields. |
| OPC-UA | Protocol description : The full name is OPC Unified Architecture (OPC Unified Architecture), which is an open source, platform-independent standard protocol; through this protocol, devices using different systems can communicate by sending messages between the client and the server through the network. . OPC-UA is more suitable for remote access. Application scenarios : Manufacturing software suitable for field equipment, control systems, manufacturing execution systems, enterprise resource planning systems and other application fields. |
| OPC-YES | Protocol description : OPC-DA is suitable for single system data access. OPC-DA is a real-time data access specification that defines relevant standards including data value, update time and data quality information. Application scenario : Suitable for data exchange between multiple vendors' devices and control applications. |
| LoRa | Protocol description : LoRa is a low-power local area network wireless standard developed by Semtech. It solves the technical problem of farther transmission distance than other wireless methods under the same power consumption conditions, and achieves low-power consumption and long-distance communication. Unite. Application scenarios : Mainly in various fields such as smart cities, smart buildings, smart homes, smart agriculture, and wireless industry. |
| ZigBee | Protocol description: ZigBee is a wireless communication protocol for low-speed and short-distance transmission. It is a highly reliable wireless data transmission network. Its main features are low speed, low power consumption, low cost, support for a large number of online nodes, and support for a variety of online topologies. Low complexity, fast, reliable and safe. ZigBee technology is a new technology that has appeared recently. It mainly relies on wireless networks for transmission. It can conduct wireless connections at short distances and is a wireless network communication technology. Application scenarios: It has been widely used in industry, agriculture, smart home and other fields. |
| Bluetooth | Protocol description: Bluetooth technology is an open global specification for wireless data and voice communications. It is a special short-range wireless technology connection that establishes a communication environment for fixed and mobile devices based on low-cost short-range wireless connections. Application scenarios: Bluetooth can exchange wireless information between many devices including mobile phones, PDAs, wireless headsets, laptops, related peripherals, etc. |
Comparison of Bluetooth, WiFi, and ZigBee protocols
At present, the advantage of WiFi is that it is widely used and has been popularized in thousands of households; the advantage of ZigBee is low power consumption and self-organizing network; the advantage of UWB carrierless wireless communication technology is the transmission rate; the advantage of Bluetooth is simple networking. However, these three technologies also have their own shortcomings, and no technology can fully meet all the requirements of smart homes.
The emergence of Bluetooth technology makes short-distance wireless communication possible, but its complex protocol, high power consumption, and high cost are not suitable for industrial control and home networks that require low cost and low power consumption. In particular, the biggest obstacle of Bluetooth is the limited transmission range. Generally, the effective range is about 10 meters. Problems such as weak anti-interference ability and information security issues are also the main factors restricting its further development and large-scale application.
WiFi is also a short-distance wireless transmission technology that can access wireless signals at any time. It is highly mobile and is more suitable for use in office and home environments. Of course, WiFi also has a fatal shortcoming. Since WiFi uses radio frequency technology, which sends and receives data through the air and uses radio waves to transmit data signals, it is more susceptible to external interference.
ZigBee is an internationally accepted wireless communication technology . Each of its network ports can access up to more than 65,000 ports, which is suitable for use in home, industry, agriculture and other fields. However, Bluetooth and WiFi network terminals can only access 10. Port, obviously cannot meet the needs of the family. ZigBee also has the advantages of low power consumption and low cost.
02
Protocol
| protocol | Protocol description and application scenarios |
| MQTT | Protocol description: MQTT is a lightweight publishing and subscribing information transmission protocol based on the TCP/IP protocol. It features compact messages, lightweight and reliable, and supports QoS. Application scenarios: It is one of the recommended protocols for the Internet of Things industry and is widely used in scenarios such as smart hardware, Internet of Vehicles, energy, and electricity. |
| HTTPS | Protocol description: HTTP protocol Hypertext Transfer Protocol, which transmits data based on the request/response model. Application scenario: Suitable for scenarios where device hardware and network bandwidth are sufficient. |
| CoAP | Protocol description : CoAP (Constrained Application Protocol) is a web-like protocol in the Internet of Things world, using a request/response interaction model. The protocol design is refined and uses the UDP protocol for data transmission, which is suitable for low-power devices with limited resources, especially NB-IoT devices. Application scenarios : It is widely used in low-power devices with limited resources such as water meters and electricity meters. |
| TCP | Protocol description : A standard developed and adopted internally by the manufacturer. Private protocols are flexible. They are often used within a certain company or organization, can be customized on demand, are easy to upgrade, and have good flexibility. The specific implementation requires manual deployment by customers. |
| UDP | Protocol description : UDP (User Datagram Protocol) is a connectionless protocol that does not provide reliability and flow control of data transmission, but has lower latency and less overhead. Application scenarios : Mainly used for real-time data transmission and fast communication between devices, including real-time video and audio streaming transmission, sensor data collection and control signal transmission, broadcast and multicast, etc. Because the UDP protocol has the characteristics of low latency, low overhead, and no need to establish a connection, it can meet application scenarios with high requirements for fast transmission and real-time performance in the Internet of Things. |
Comparison of MQTT and CoAP protocols
MQTT is a many-to-many communication protocol used to transmit messages between different clients through an intermediate proxy, decoupling producers and consumers, and allowing the client to publish and let the agent decide routing and copy messages. Although MQTT supports some persistence, it is best used as a real-time data communication bus.
CoAP is primarily a point-to-point protocol used to transmit stateful information between clients and servers. While observing resources is supported, CoAP is best suited to a stateful transfer model and is not entirely event-based.
The MQTT client establishes a long-lived TCP connection. This usually means there is no problem. Both the CoAP client and the server are sending and receiving UDP packets. In a NAT environment, tunneling or port forwarding can be used to allow CoAP, or like LWM2M, the device may first Initialize the front-end connection.
MQTT不提供支持消息打类型标记或者其他元数据帮助客户端理解，MQTT消息可用于任何目的，但是所有的客户端必须知道向上的数据格式以允许通讯，CoAP，相反地，提供内置支持内容协商与发现，允许设备相互探测以找到交换数据的方式。
03
行业协议
| 协议 | 协议描述和应用场景 |
| GB/T28181 | 协议描述：国家标准GB/T 28181—2016《公共安全视频监控联网系统信息传输、交换、控制技术要求》,是视频监控领域的国家标准。 应用场景：视频联网传输和设备控制。 |
| JT/T808 | 协议描述：《道路运输车辆卫星定位系统终端通信协议及数据格式》，主要用于“两客一危”车辆。 应用场景：交通行业应用。 |
| GB3761 | 协议描述：是一种国标电表协议插件，采用新型的数据采集技术，将电能表的实时工况数据转换成电信号，提供给计量系统，并能进行电能的实时记录、统计、抄表和结算等。 应用场景：电表。 |
| DL/T645 | 协议描述：DL/T 645是多功能电能表与数据终端设备进行数据交换式的物理连接和协议的规范和标准，本设备依据协议采用中国电力企业联合会提出的DL/T 645-2007《多功能电能表》标准规约，实现设备与多功能电能表的信息通信。 应用场景：电表。 |
| IEC104 | Protocol description: The IEC104 protocol is formulated by the International Electrotechnical Commission. The IEC104 protocol is a standard that uses the network protocol TCP/IP to transmit the application service data unit (ASDU) of IEC101. This standard provides a communication protocol basis for the network transmission of telecontrol information. By combining the 104 protocol with the ASDU of the 101 protocol, the standardization of the protocol and the reliability of communication can be well ensured. Application scenarios: electric power, urban rail transit. |
| HJ212 | Protocol description: "Data Transmission Standard for Pollutant Online Monitoring (Monitoring) System" is a data transmission standard protocol used in the environmental protection industry. Application scenario: environmental protection industry. |
| SL651 | Protocol description: "Hydrological Monitoring Data Communication Protocol", hydrological monitoring and other equipment need to follow this specification. Application scenario: hydrological monitoring. |
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