The switch, especially the access layer switch, is the equipment that we contact most in daily network fault maintenance. They are bridges between users and switching and routing devices. However, no matter how good the performance of the switch equipment is, there will be potential failures. Just like people, no matter how healthy they are, there will always be some small problems. It is good to be able to stop them in the future. It is said that occasional problems are unavoidable, but they should be dealt with in a timely manner after the fault occurs, and the fault point should be found and eliminated as soon as possible. To do this, it is necessary to understand the types of switch failures and the ability to analyze and handle them. Generally speaking, common failures of network switches include power failure, port failure, module failure, etc. Next, let Wuhan Hailing Optoelectronics Department introduce the common faults of the network switch in detail. Let's see.

1. Power failure: the power supply is damaged or the fan stops running due to unstable external power supply, aging power cord or lightning stroke. Or because of the power supply, other parts of the machine are damaged, and the switch will have problems.

If the POWER indicator on the switch panel is green, it indicates that it is normal; If the LED is off, the switch is not powered normally. Such problems are easy to find, solve and prevent.

For such faults, the first thing to do is to provide external power. Generally, independent power supply and voltage regulator are provided by introducing independent wires to avoid transient high voltage or low voltage. If conditions permit, an uninterruptible power supply can be added to ensure the normal power supply of the switch. Some UPS provide voltage regulation, while others provide voltage regulation. Be careful when selecting. Set professional lightning protection measures in the machine room to avoid damaging the switch by lightning. There are many professional companies doing lightning protection engineering, which can be considered when implementing network cabling.

2. Port fault: The whole network is running normally, but individual machines cannot communicate normally.

Cause of failure: This is the most common hardware failure. Be careful when plugging and unplugging connectors, whether it is an optical fiber port or a twisted pair RJ-45 port. If the optical fiber plug is accidentally dirty, the optical fiber port may be polluted and cannot communicate normally. We often see that many people prefer live plug connectors, which is theoretically possible, but this inadvertently increases the port failure rate. Improper handling will also cause physical damage to the port. If you buy a larger crystal head, it is easy to damage the port by inserting it into the switch. In addition, if the twisted pair of the connection port is exposed outdoors and the cable is struck by lightning, the port of the connected switch will be damaged, or more unpredictable damage will be caused.

Solution: Generally speaking, the port failure is the damage of individual ports. Check the problem computer first. After troubleshooting the computer connection port, you can replace the connected port to determine whether it is a port problem. If the port is replaced and the problem can be solved later, we can further determine the cause of the port. After power failure, clean the port with an alcohol swab. If the port is really damaged, the only way is to replace the port. In addition, be careful when plugging and unplugging the connector, whether it is an optical fiber port or a twisted pair RJ-45 port. Hot line operation is not recommended during plugging.

3. Module failure: The switch is composed of many modules, such as stacking module, management module (i.e. control module), expansion module, etc. These modules have different external interfaces. Some faults can be identified by the indicators on the module.

Failure reason: The switch is a variety of modules. This kind of failure may occur if the module is plugged or unplugged carelessly or the switch encounters the module during transportation. It may also be caused by unstable power supply.

Solution: The probability of failure of these modules is very small, but once a problem occurs, it will suffer huge economic losses. Therefore, on the premise of maintaining stable power supply, you should be very careful when removing modules or moving switches. When troubleshooting such faults, first ensure that the power supply of the switch and module is always supplied, then check whether each module is plugged in the correct position, and finally check whether the cable connecting the module is normal. 4. Circuit board failure: In the computer room, some computers often fail to access the server. At first, it was thought that the network cabling was not standardized, and the network card settings were modified by students, so the computer room administrator often tested the network cables and reset the network configuration of the system. However, after repeated maintenance, the network connection of these computers is still intermittent. Eventually, all computers in this group cannot access the Internet. At the same time, it was found that all the connection indicators of the switches connected to this group of computers were irregular. flash of light.

Fault cause: The switch is generally composed of the main circuit board and the power circuit board. This fault is generally caused by the problems of these two parts. The main factors that cause the circuit board to fail to work normally are: the components on the circuit board are damaged or the base plate is poor, the hardware workmanship is improper, the model of the circuit board after the hardware update is inappropriate, compatibility problems, etc.

Solution: First, judge whether the main circuit board or the power circuit board is faulty. First, check from the power part. When the load of the main circuit board is removed, measure the power with a multimeter to see whether the measurement indicators are normal. If not, switch to AT power supply, input the power to the main circuit board, restore the normal brightness and color of the indicator on the front panel of the switch, and communicate with the computer connected to the switch normally, It indicates that there is a problem with the power circuit board. If the above operations do not work, the problem should be on the main circuit board.

5. Backplane fault: The external power supply environment is normal, but the internal modules of the switch cannot work normally.

Cause of fault: Since all modules of the switch are connected to the backplane, if the switch is working in a humid environment, the circuit board is short circuited due to moisture, or components are damaged due to high temperature, lightning stroke, etc As a result, the circuit board fails and cannot work normally.

Solution: If the external power supply is normal, but the internal module of the switch does not work properly, the backplane may be broken. There is no other solution to this problem, but there is only one solution: replace the backplane, because maintenance made it up. may not. In order to effectively prevent such failures, the most important thing is to provide the switch with a working environment that conforms to the standard indicators provided by the manufacturer.