How to quickly troubleshoot industrial switches

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As the saying goes, people will get sick and machines will break. It is inevitable that the machine will fail more or less when it is running, and the failure of the industrial switch during operation is inevitable, but it should be dealt with quickly after the failure, and the fault point should be detected as soon as possible to eliminate the failure. When it is more complicated to analyze the fault, you must start with simple operation or configuration. This can speed up the troubleshooting and improve the rate. Let me first talk about some steps how to troubleshoot industrial switches.
1. Power failure
The power supply is damaged or the fan stops due to unstable external power supply, aging of the power supply line or lightning strikes, so that it cannot work normally. Or damage to other components in the machine due to power supply will cause problems to the switch. If the POWER indicator on the switch panel is green, it is normal; if the indicator is off, it means that the switch is not normally powered. Such problems are easy to find and easy to solve, and they are also relatively easy to prevent. In response to such failures, the external power supply should be done first. Generally, an independent power line is introduced to provide an independent power supply, and a voltage regulator is added to avoid instantaneous high-voltage or low-voltage phenomena. If conditions permit, you can add a UPS (uninterruptible power supply) to ensure the normal power supply of the switch, some UPS provide voltage stabilization function, and some do not, you should pay attention when choosing. Set up professional lightning protection measures in the equipment room to avoid lightning damage to the switch. Now there are many professional companies doing lightning protection projects, which can be considered when implementing network cabling.
2. Port failure
This is a relatively common hardware failure. Whether it is an optical fiber port or a twisted pair RJ-45 port, you must be careful when plugging or unplugging the connector. If you accidentally dirty the optical fiber plug, it may cause the optical fiber port to be contaminated and cannot communicate normally. We often see that many people like live plug-in connectors, which is theoretically possible, but this also inadvertently increases the incidence of port failures. Careless handling may also cause physical damage to the port. If the purchased crystal head is too large, it is easy to damage the port when it is inserted into the switch. In addition, if a section of the twisted pair connected to the port is exposed outdoors, in case this cable is struck by lightning, it will cause the connected switch port to be damaged or cause more unpredictable damage. In general, a port failure is one or several ports damaged. Therefore, after troubleshooting the computer connected to the port, you can determine whether it is damaged by replacing the connected port. In case of such failures, you can clean the port with an alcohol cotton ball after the power is turned off. If the port is indeed damaged, it can only be replaced.
3. Module failure
Industrial switches are composed of many modules, such as stacking modules, management modules (also called control modules), and expansion modules. The chances of these modules failing are very small, but once problems occur, they will suffer huge economic losses. If you are careless when inserting or removing the module, or when the switch is transported, or if the power supply is unstable, it may cause such failures. Of course, the three modules mentioned above all have external interfaces, which are easier to identify, and some can also identify faults through the indicator lights on the module. For example, there is a flat trapezoidal port on the stacking module, or some switches have a USB-like interface. There is a CONSOLE port on the management module, which is used to establish a connection with the network management computer for easy management. If the expansion module is connected by fiber, there will be a pair of fiber interfaces. When troubleshooting such faults, first ensure that the power supply of the switch and the module is properly supplied, then check whether each module is plugged in the correct position, and after comparison, check whether the cable connecting the module is normal. When connecting the management module, it is also necessary to consider whether it uses the specified connection rate, whether there is a parity check, whether there is data flow control and other factors. When connecting the expansion module, you need to check whether it matches the communication mode, for example: whether to use full-duplex mode or half-duplex mode. Of course, if it is confirmed that the module is faulty, there is only one solution, that is, you should immediately find a supplier to replace it.
4. Backplane failure
Each module of the industrial switchboard is plugged into the backplane. If the environment is humid, the circuit board is wet and short circuit, or the components are damaged due to high temperature, lightning strike and other factors
The circuit board is not working properly. For example: poor heat dissipation performance or too high ambient temperature leads to an increase in the internal temperature of the unit, causing the components to burn out. Under the condition that the external power supply is normal, if the internal modules of the switch are not working properly, it may be that the backplane is broken. In this case, even an electrical maintenance engineer may have no choice. Board.
5. External factors
Due to the presence of viruses or hacking attacks, it is possible that a host sends a large number of data packets that do not meet the encapsulation rules to the connected port, causing the switch processor to be too busy, causing the data packets to be too late to forward, which in turn causes buffer overflow Package phenomenon. Another situation is the broadcast storm, which not only takes up a lot of network bandwidth, but also takes up a lot of CPU processing time. If the network is occupied by a large number of broadcast data packets for a long time, normal point-to-point communication cannot be performed normally, and the network speed will become slow or paralyzed. A failure of a network card or a port may cause a broadcast storm. Because the switch can only divide the conflict domain, but not the broadcast domain (in the case of no VLAN division), when the number of broadcast packets accounts for 30% of the total communication, the transmission efficiency of the network will decrease significantly.
6. Improper configuration
Beginners are not familiar with switches, or due to different switch configurations, administrators often have configuration errors when configuring switches. For example, incorrect VLAN division leads to network disconnection, ports are closed by mistake, and the mode configuration of the switch and network card does not match. Such failures are sometimes difficult to find and require some experience accumulation. If you cannot ensure that the user's configuration is faulty, please restore the factory default configuration first, and then configure it step by step. It is better to read the manual before configuration, which is also one of the habits that the network management should develop. Each switch has a detailed installation manual, user manual, and a detailed explanation of each type of module. Since many manuals for switches are written in English, users with poor English can consult with the supplier's engineers for specific configuration.
7. System error
The switch system is a combination of hardware and software. There is a refreshable read-only memory inside the switch, which stores the software system necessary for this switch. This type of error is also the same as our common Windows and Linux. Due to the design at the time, there are some loopholes. When the conditions are suitable, it will cause the switch to be fully loaded, lost, and wrong. Therefore, the switch system provides methods such as Web and FTP to download and update the system. Of course, errors may occur when upgrading the system.
For such problems, we need to develop the habit of constantly browsing the information of equipment manufacturers. If there are new systems launched or new patches, please update in time.
8. Cable fault
In fact, this kind of fault is theoretically not a fault of the switch itself, but in actual use, cable faults often cause the switch system or port to not work properly, so this type of fault is also classified as a switch hardware fault. For example, the connectors are not tightly connected, the order of the cables is incorrect or not standardized, and the cables should be connected with crossover cables but with straight cables. The two optical fibers in the optical cable are interleaved. The wrong circuit connection leads to network loops. Wait.
Judging from the above kinds of hardware failures, the poor environment of the equipment room can easily lead to various hardware failures, so when we build the equipment room, we must first do lightning protection and grounding and power supply, indoor temperature, indoor humidity, anti-electromagnetic interference, The construction of anti-static and other environments provides a good environment for the normal operation of network equipment.

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