Several minutes to learn about switch troubleshooting

In the daily use of switches, There will be various problems. The first problem is that the environment is wet, the circuit board is damp and short-circuited, or the components are due to high temperature and other problems, the following article describes the classification and troubleshooting of switch faults.

Common switch fault categories: Several smart solutions are provided. The following describes switch fault categories and common fault solutions. The superior performance and price of vswitches are greatly reduced, promoting the rapid popularization of vswitches. Network administrators often encounter a variety of switch faults at work. How can they quickly and accurately find and eliminate faults?

As vswitches are widely used in the company's network, from the low end to the middle end, from the middle end to the high end, almost every level of products are involved, so the probability of a switch failure is better than that of a router, hardware firewalls are much higher, which is why we first discuss the classification of switch faults and troubleshooting steps.

Switch fault classification:

Switch fault classification can be divided into two categories: hardware fault and software fault. A hardware fault mainly refers to the failure of the power supply, backplane, module, port, and other components of the switch. It can be divided into the following categories. Switch fault classification: backplane fault: All modules of the switch are connected to the backplane.

If the environment is wet, the circuit board is short-circuited by the tide, or the components are damaged due to high temperature, lightning, and other factors, the circuit board will not work properly. For example, if the heat dissipation performance is poor or the ambient temperature is too high, the temperature in the machine increases and the components are burned out.

When the external power supply is normal, if the internal modules of the switch cannot work normally, the backboard may be broken. In this case, even the electrical maintenance engineer may not be able to handle this problem, the only way is to change the backplane.

Switch fault type: Power Supply Fault: the power supply is damaged or the fan is stopped due to unstable external power supply, aging of power supply lines, lightning strikes, and other reasons. Other components in the machine are often damaged due to power supply.

If the POWER indicator on the panel is green, it indicates that it is normal. If the indicator is off, it indicates that the switch has no normal POWER supply. Such problems can be easily discovered, solved, and prevented. In view of such faults, the external power supply should be prepared first.

Generally, an independent power line is introduced to provide an independent power source and a voltage regulator is added to avoid transient high voltage or low voltage. If conditions permit, you can add UPS (uninterruptible power supply) to ensure the normal power supply of the switch. Some UPS provide the regulator function, while others do not. Pay attention to the selection. Set up professional lightning protection measures in the IDC room to avoid lightning damage to the switch. Now there are many professional companies engaged in anti-ray engineering, which can be considered when implementing network cabling.

Switch fault classification: Module Fault: a switch is composed of many modules, such as stack module, management module (also called control module), and extension module. The failure rate of these modules is very small, but once a problem occurs, it will suffer huge economic losses. Such failures may occur if you are not careful when plugging or removing modules, or when the switch is moved, or when the power supply is unstable.

Of course, the three modules mentioned above have external interfaces, which are easy to identify. Some modules can also identify faults through the indicators on the module. For example, a stacked module has a flat trapezoid port, or some switches have interfaces similar to USB. The management module has a CONSOLE port for establishing a connection with the network management computer to facilitate management. If the expansion module is connected to an optical fiber, there will be a pair of Optical Fiber interfaces.

In troubleshooting such a fault, first ensure that the power supply of the switch and module is normal, then check whether the modules are inserted in the correct position, and finally check whether the cables of the connection module are normal. When connecting to the management module, you also need to consider whether it uses the specified connection rate.

Whether there are parity, whether there are data flow control and other factors. When connecting the expansion module, you need to check whether the communication mode is matched, for example, whether the full or half duplex mode is used. Of course, if the module is faulty, there is only one solution, that is, you should immediately contact the supplier for replacement.

Switch fault classification: cable fault: In fact, this type of fault theoretically does not belong to the switch's own fault. However, in actual use, cable failure often causes the switch system or port to fail to work normally, therefore, such faults are also classified as switch hardware faults.

For example, if the connection is not tight, the cables are arranged incorrectly or in an irregular order during cable preparation. When connecting the cables, the cables should be connected using a straight line. The two optical fiber cables in the optical fiber cables are staggered, network loops are caused by incorrect line connections. Switch fault type: Port fault:

This is the most common hardware fault, whether it is fiber port or twisted pair RJ-45 port, in the plug-in connector must be careful. If the optical fiber plug is accidentally soiled, the optical fiber port may be contaminated and cannot communicate normally. Generally, one or more ports are damaged.

Therefore, after the failure of the computer connected to the port is ruled out, you can change the connected port to determine whether it is damaged. In case of such a fault, you can use alcohol cotton balls to clean the port after the power is off. If the port is damaged, you can only change the port.

From the above several hardware faults, poor data center environments can easily lead to various hardware faults, so when we build data centers, we must first build the anti-ray grounding and power supply, indoor temperature, indoor humidity, anti-electromagnetic interference, anti-static and other environments to provide a good environment for the normal operation of network equipment.

General troubleshooting steps for switch faults:

Vswitch faults are diverse, and different faults have different forms. In case of failure analysis, you must use various phenomena to flexibly use troubleshooting methods (such as troubleshooting, comparison, and replacement) to locate the fault and promptly eliminate it. Vswitch fault classification and troubleshooting methods: Division:

When we face the fault and analyze the problem, we have learned to use the exclusion method to determine the direction of the fault. Based on the observed fault phenomenon, this method lists all possible faults as much as possible, and then analyzes and resolves them one by one. We should follow the principle of simplicity to complexity to improve efficiency. This method can be used to cope with various faults. However, maintenance personnel must have a strong logical thinking and have a thorough understanding of switch knowledge.

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