The Main Parameters of Layer 2 and Layer 3 Industrial Switch

Industrial Switch is an industrial Ethernet switch, which is an Ethernet switch device used in the field of industrial control. Due to the network standard adopted, it has good openness and wide application; it can adapt to low temperature and high temperature, strong anti-electromagnetic interference, anti-salt fog, strong shock resistance .Industrial switches are important equipment in the field of industrial data communication. Currently, the popular industrial switches are divided into Layer 2 switches and Layer 3 switches. Today, we will mainly learn about some of their main parameters of Layer 2 and Layer 3 industrial switches.

Layer 2 switches work at Layer 2 (data link layer) of the OSI model, so they are called Layer 2 switches.The development of Layer 2 switching technology has been relatively mature. Layer 2 switches are data link layer devices, which can identify the MAC address information in data frames, forward them according to the MAC addresses, and record these MAC addresses and corresponding ports in their own internal in an address table.

Main parameters of Layer 2 industrial switches

1. Port types of industrial switches: twisted pair interface, optical fiber interface, GBIC slot, SFP slot;

2. Port rates of industrial switches: There are mainly two types: 100Mbps and 1000Mbps. The common rates are n*100Mbps, n*1000Mbps, n*100Mbps+m*1000Mbps. When selecting the number of ports, appropriate redundancy and high density should be used. ;

3. The smaller the delay time of the industrial switch, the better;

4. The more MAC addresses the industrial switch can memorize, the better;

5. The more VLANs supported by industrial switches, the better;

6. Industrial switch extension mode: there are two types of cascade and stacking. Cascading refers to the communication between industrial switches through a port, so that the connection between industrial switches becomes a network bottleneck. Stacking refers to the use of dedicated modules and the cable realizes high-speed non-blocking connection, and can be uniformly configured and managed;

7. Link aggregation of industrial switches: use the port aggregation protocol to bind multiple ports together to multiply the connection bandwidth and achieve link backup;

8. Management functions of industrial switches.

A three-layer switch is a switch with some router functions, which works on the third layer of the OSI network standard model: the network layer.The most important purpose of the Layer 3 switch is to speed up the data exchange within the large-scale local area network. The routing function it has is also for this purpose, and it can achieve one routing and multiple forwarding.

Regular processes such as data packet forwarding are implemented by hardware at high speed, while functions such as routing information update, routing table maintenance, routing calculation, and routing determination are implemented by software.

Main Parameters of Layer 3 Industrial Switches

1. Forwarding rate (throughput): Throughput (Mpps) = number of 10 gigabit ports * 14.88Mpps + number of gigabit ports * 1.488Mpps + number of 100 megabit ports * 0.1488Mpps, if the nominal throughput of the industrial switch is greater than or Equal to the calculated value, the line speed (data transmission speed on the transmission line) can be achieved during Layer 3 switching; the theoretical throughput of a gigabit port when the packet length is 64B is 14.88Mpps (=1000000000bps/8bit/(64+ 8+12)byte);

2. The backplane bandwidth of the industrial switch: refers to the maximum amount of data that can be handled between the interface processor or interface card of the industrial switch and the data bus. To achieve full-duplex non-blocking transmission of the network, the minimum backplane bandwidth must be met: The formula is backplane bandwidth = number of ports * port rate * 2;

3. Scalability of industrial switches: the number of slots and the type of modules;

4. System redundancy of industrial switches: including power modules and management engines;

5. Management functions of industrial switches: support SNMP protocol and provide a friendly management community.