What's the difference among SNMP, Modbus protocol and CAN protocol?

The core difference among SNMP, Modbus, and CAN lies in their completely different design goals: SNMP is designed specifically for network device management (such as routers and servers), Modbus focuses on industrial device data exchange (such as PLCs and sensors), and CAN is aimed at real-time control scenarios (such as automobiles and industrial control). The three have significant differences in protocol positioning, application areas, and communication logic.

Specific comparisons can be made from four key dimensions:

1. Protocol positioning and core purpose

-SNMP: It belongs to the network management protocol, with the core of "monitoring+operation and maintenance", used to collect network device status (such as bandwidth, CPU usage), report faults, and does not involve device control logic.

-Modbus: It belongs to the industrial application layer protocol, with the core being "data exchange", which enables parameter reading (such as temperature) and instruction issuance (such as valve control) between industrial devices, relying on underlying buses such as RS485/TCP.

-CAN: It belongs to the underlying control protocol (covering the physical layer and data link layer), with the core of "real-time control", directly carrying device control signals (such as car engine commands), and comes with a high reliability mechanism.

2. Communication architecture

-SNMP: "Manager Agent" architecture, where one manager can manage multiple agent devices, and agents can actively report faults (Trap messages) without priority distinction.

-Modbus: It is mainly based on a "master-slave architecture", with only one master station initiating requests and the slave station passively responding, unable to actively send data, and does not support multiple master stations.

-CAN: "Multi master equal architecture", all nodes can actively send data, and priority is determined through ID arbitration (the smaller the ID, the higher the priority). Emergency control signals can be transmitted first.

3. Application scenarios and device types

-SNMP: Applied in the field of IT networks, it manages network devices such as routers, switches, servers, firewalls, etc. It is commonly used in enterprise data centers and data centers.

-Modbus: Applied in the field of industrial automation, it connects industrial equipment such as PLCs, sensors, frequency converters, and instruments. It is commonly used in production lines, water plants, and substations (non control data).

-CAN: Applied in the field of real-time control, such as automotive electronics (engine, chassis control), industrial machine tools (axis control), medical equipment (surgical robots), with extremely high requirements for real-time performance and reliability.

4. Security and real-time performance

-SNMP: Low real-time performance (second level response), weak security of SNMP v1/V2C (only community name authentication), although SNMP v3 supports encryption, the core does not pursue real-time performance.

-Modbus: Medium real-time performance (millisecond level), no built-in encryption mechanism, relying solely on CRC check to ensure data integrity, and security relies on underlying bus isolation.

-CAN: Extremely real-time (microsecond level), with built-in bit error detection and automatic retransmission, ensuring high reliability without additional encryption, suitable for control signal transmission.

If your project needs to select from these three types of agreements, we can help you organize a decision list based on specific scenarios (such as whether real-time control and management of object types are required).