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What functions are commonly used in industrial switches? switches are also called industrial Ethernet switches, which work on the second layer of OSI (data link layer, see the definition of "wide area network"), based on MAC (media access control address of network card) identification, and can complete encapsulation and forwarding of data Packet-enabled network devices. So, what are the functions of industrial switches?

The industrial switch regenerates the information and forwards it to the designated port after internal processing, so it has the ability of automatic addressing and switching. All ports on the industrial switch have exclusive channel bandwidth to ensure fast and efficient data transmission on each port. Because the industrial switch sends each information packet independently from the source port to the destination port according to the destination address of the transmitted information packet, instead of sending it to all ports, avoiding conflicts with other ports, therefore, the industrial switch can communicate with each other at the same time. These packets are transmitted without impact, and transmission collisions are prevented, increasing the actual throughput of the network.

There is no essential difference between the industrial Ethernet switch itself and the commercial network in terms of data link layer, network layer, protocol layer, etc., but for the real-time requirements of industrial control, industrial Ethernet solves the real-time communication, network security, essential Safety and safety and explosion-proof technology and other technical issues, and adopt some measures suitable for industrial environments, such as waterproof, anti-vibration... The core is still not essentially different from commercial Ethernet, which is the same as PC and industrial computer same difference between.

1. Network Security

In advanced industrial applications, cyber security has become an unsolved problem. However, many domestic manufacturers (such as Dongtu, Mosha, Maiwei Communication, etc.) produce a series of Web network managed industrial switches that provide multiple functions for network security issues in the LAN.

1. Password—has a multi-level user password to avoid unauthorized access and settings.

2.Enable/Disable Ports to open and close ports - close unused ports.

3. 802.1q VLAN predefines WLAN on the industrial switch to realize logical isolation between physical ports.

4. 802.1x port-based network access control—lock the ports of industrial switches so that only legitimate users can communicate.

5. MAC Based Port Security MAC-based port security - to protect the ports of industrial switches so that they can only communicate with specific devices or MAC addresses.

2. Port device status

Set the speed, duplex, auto-negotiation, flow control, etc. of each port to establish a correct connection with devices that cannot negotiate or have specific settings.

3. Port rate limit

Configure rate limits for ports, including ingress and egress rate limits. The types of port restrictions include all unicast packets, multicast packets, and broadcast packets. The ingress speed refers to the actual speed flowing from other devices such as PCs to the industrial switch port. The export speed refers to the actual speed between the port of the industrial switch and the equipment used. If both the ingress and egress velocities between two device connection ports are restricted, the actual velocity will be the smaller of the two.

4. The storm suppresses the storm

Wreak havoc on networks and cause failures of network-connected devices. In mission-critical applications, it can be catastrophic. Filter broadcast packets based on user-defined limits to suppress storms.

5. Quality of Service (IEEE802.1p)

Due to the frame buffer queue and first-come-first-processing mechanism of industrial switches, delays will occur when the network load is heavy. IEEE802.1p allows data packets in high-priority queues to stay in the industrial switch for a short time, while data packets in low-priority queues are the opposite.

6. Virtual local area network VLAN (IEEE802.1q)

A virtual local area network (VLAN) is a method of creating an independent logical network from an actual physical network. This method enables several virtual local area networks to exist in an actual physical network at the same time. VLAN can effectively reduce the scope of broadcasting and facilitate network management. In fact, if a router is added between these different virtual network segments, they can still exchange data through the router. VLAN can effectively suppress the occurrence of broadcast storms.

7. Multicast snooping IGMP Snooping

The Layer 2 device running IGMP Snooping analyzes the received IGMP packets, establishes a mapping relationship between ports and MAC multicast addresses, and forwards multicast data according to the mapping relationship. When the Layer 2 device does not perform IGMP Snooping, the multicast data is broadcast on the Layer 2; when the Layer 2 device runs IGMP Snooping, the multicast data of the known multicast group will not be broadcast on the Layers are multicast to designated recipients.

Eight, fast ring network (MW-Ring)

MW-Ring can connect industrial switches with redundant links. When one of the links is disconnected, the other link can quickly and automatically recover. When the network is interrupted or the network fails, it has link redundancy and fast self-recovery capabilities. MW-Ring technology is developed and designed by Wuhan Maiwei Communication Co., Ltd. for high-reliability industrial control network applications.

9. Link Aggregation (802.3ad)

The main function of port aggregation (TRUNK) is to bind multiple physical ports (usually 2-4) into a logical channel, making it work like a channel. After bundling multiple physical links together, not only the bandwidth of the entire network is improved, but also data can be transmitted through the bound multiple physical links at the same time, which has the function of link redundancy. When the network fails or other Cause When one or more links are disconnected, the remaining links can still work.

10. Rapid Spanning Tree RSTP

The Spanning Tree Protocol is a Layer 2 management protocol. It aims to eliminate network Layer 2 loops by selectively blocking network redundant links, and it also has link backup functions.

11. Port-based network access control (802.1x)

Defines a port-based network access control mechanism, providing a method for authenticating and authorizing devices connected to LAN ports.

12. HTML web browser

Provides a simple, intuitive user interface for setup and monitoring through a standard graphical web browser. All system parameters, including detailed online help, make system setup a breeze.

13. SNMP (Simple Network Management Protocol)

The Simple Network Management Protocol (SNMP) is defined by the Internet Engineering Task Force as part of the protocols that make up the Internet. Under the condition of paying attention to a certain network device, use SNMP to monitor the network device through the network management system. The SNMP protocol consists of a series of standard network management, application layer protocols, databases, and data objects.

Fourteen, port mirroring

The port mirroring function is to copy all the sending and receiving data of one or more ports to another designated port. By specifying a port as the mirror port of other ports, you can observe all data sent and received by other ports through this port. Diagnose, debug, and analyze network faults through the port mirroring function.

15. Port statistics and remote monitoring (RMON)

Continuously updated statistics are provided for each port, including all incoming and outgoing packet counts and byte counts, as well as detailed error statistics. All support for RMON statistics, history, alarms and event groups is also provided. RMON can complete accurate data collection, analysis and detection of data flow model.

16. NTP (Simple Network Time Protocol)

Automatically synchronize the internal clock of the system with the NTP server in the network, thereby providing time correlation of events for fault analysis.

17. Event record and alarm

Record all significant events to non-volatile system logs for future failure analysis. Events include link failure and recovery, illegal access, broadcast storm detection, and self-diagnosis. Alerts provide a snapshot of recent events that the network administrator has not yet responded to. An external hardware relay releases the contacts during critical events, allowing an external controller to operate if necessary.