The switch will inevitably encounter failures during normal use. Network switch failures can cause network downtime, affecting our business, production, and damage to our property, so we have to troubleshoot and repair the switch in the shortest possible time. Here we introduce you to the 5 common hardware and 4 software failures of the switch.

5 hardware failures

Here we collect 5 common hardware issues of network switchpower failureport failuremodule failurebackplane failure, and cable failure. Let’s understand one by one:

1. Power failure

The external power supply is unstable, or the power supply line is damaged or the power supply is damaged due to aging or lightning strikes.

The switch maintenance switch means “switch” is a network device used for electrical signal forwarding. It provides an exclusive electrical signal path for any two network nodes that access the switch. The most common switch is an Ethernet switch. Other common telephone voice switches, fiber switches, and so on.

Damage to other components in the machine due to the power supply also occurs frequently. If the POWER indicator on the panel is green, it means normal; if the indicator is off, the switch is not working properly.

Such problems are easy to find, easy to solve, and most preventable. For such faults, the external power supply should be done first. The independent power supply is usually introduced to provide independent power supply, and a voltage regulator is added to avoid instantaneous high voltage or low voltage.

If conditions permit, you can add PHOTOSHOP to ensure the normal power supply of the switch. Some UPSs provide voltage regulation functions, while others do not.

Set professional lightning protection measures in the equipment room to avoid damage to the switch caused by lightning. There are a lot of professional companies doing lightning protection projects, and you can consider them when implementing network cabling.

2. Port failure

This is the most common hardware failure, whether it is a fiber port or a twisted pair RJ-45 port, be careful when plugging and unplugging connectors.

If you accidentally dirty the fiber plug, it may cause the fiber port to be contaminated and not communicate properly.

We often see that many people like to plug in and out of the joint, in theory, it is ok, but this also inadvertently increased the failure rate of the port. Careless handling can also result in physical damage to the port.

If the crystal head is purchased in a large size, it is easy to damage the port when it is inserted into the switch. In addition, if the twisted pair connected to the port is exposed to the outside, if the 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 that are damaged. Therefore, after the fault of the computer connected to the port is eliminated, it can be judged whether it is damaged by replacing the connected port. In the event of such a malfunction, the port can be cleaned with an alcohol cotton ball after the power is turned off. If the port is indeed damaged, you can only change the port.

3. Module failure

A switch consists of some modules, such as stacking modules, management modules, and expansion modules.

These modules have a low probability of failure, but in the event of a problem, they suffer huge economic losses. If you accidentally insert or remove a module, or if you are bumped when you move the switch, or if the power supply is unstable, it may cause such a fault.

Of course, the three modules mentioned above have external interfaces, which are relatively easy to identify, and some can also identify faults through the indicators on the module. For example, there is a flat trapezoidal port on the stacking module, or some switches are similar to a USB interface. The management module has a CONSOLE port for establishing a connection with the network management computer for easy management. If the expansion module is a fiber optic connection, there will be a pair of fiber optic interfaces.

When troubleshooting such a fault, first ensure that the power supply of the switch and module is properly supplied, then check whether each module is plugged in the correct position, and finally check whether the cable of the connected module is normal. When connecting the management module, it should also consider whether it adopts the specified connection rate, whether there is parity, whether there are data flow control and other factors.

When connecting an expansion module, you need to check if it matches the communication mode, for example, whether to use full-duplex mode or half-duplex mode. Of course, if you confirm that the module is faulty, there is only one solution, that is, you should contact the supplier immediately for a replacement.

4. Backplane failure

Each module of the switch is plugged into the backplane. If the environment is wet, the board is short-circuited by moisture, or the components are damaged due to high temperature, lightning strikes, etc., the board will not work properly.

For example, if the heat dissipation performance is not good or the ambient temperature is too high, the temperature inside the machine rises, and the components are burned out. In the case of the normal power supply of the external power supply, if the internal modules of the switch are not working properly, it may be that the backplane is broken. Even if it is an electrical maintenance engineer, there is no way to do it. The only way is to replace the backplane.

5. Cable failure

This type 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 fail to work properly, so this type of fault is also classified as a switch hardware failure.

For example, the connector is not tightly connected. The cable is arranged in the wrong order or not standard. When the cable is connected, the crossover cable should be used but the direct connection is used. The two fibers in the cable are connected in an interlaced manner. The wrong line connection leads to the network loop. Wait.

We have learned from the above that the hardware problems of the switch are often caused by poor computer room environment, which can easily lead to various hardware failures. Therefore, when building the equipment room, we must first do lightning protection grounding, power supply, indoor temperature, and indoor humidity. The construction of anti-electromagnetic interference and anti-static environment provides a good environment for the normal operation of network equipment.

4 software failures

1. System error

The switch system is a combination of hardware and software. Inside the switch is a refreshable read-only memory that holds the software system necessary for the switch. This type of error is also common to us.

S, Linux, because of the design reasons at the time, there are some loopholes, when the conditions are right, it will lead to the switch full load, packet loss, wrong package and so on. The switch maintenance switch has multiple ports, each of which has a bridge function to connect to a LAN or a high-performance server or workstation. Switches are sometimes referred to as multiport bridges.

B, TFTP, etc. to download and update the system. Of course, when upgrading the system, errors may occur. For such problems, we need to develop the habit of frequently browsing the equipment manufacturer’s website. If there is a new system launch or a new patch, please update it in time.

2. Improper configuration

Beginners are unfamiliar with switches, or because various switches are configured differently, administrators often have configuration errors when configuring switches.

The switch maintenance switch means “switch” is a network device used for electrical signal forwarding. It provides an exclusive electrical signal path for any two network nodes that access the switch. The most common switch is an Ethernet switch. Other common telephone voice switches, fiber switches, and so on.

For example, if the VLAN is incorrectly partitioned, the network is unreachable, the port is incorrectly shut down, and the mode configuration of the switch and the NIC does not match. Such faults are sometimes difficult to find and require a certain amount of experience. If you are not sure that there is a problem with the user’s configuration, first restore the factory default configuration and then configure it step by step. It is best to read the manual before the configuration, which is one of the habits that network management has to 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 before making specific configurations.

3. Lost password

This may be something that every administrator has ever experienced. Once you forget your password, you can restore or reset your system password through certain steps. Some are simpler, just press a button on the switch. And some need to be solved through certain steps. Such a situation usually occurs when human forgetting or switch failure causes data loss.

4. External factors

Due to the existence of viruses or hackers, a host may send a large number of packets that do not meet the encapsulation rules to the connected port, causing the switch processor to be too busy, causing the packets to be too late to be forwarded, resulting in a 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 packets for a long time, the normal point-to-point communication cannot be performed normally, and the network speed will be slow or embarrassing.

A network card or a port failure may cause a broadcast storm. Since the switch can only divide the collision domain and cannot divide 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 be significantly reduced.

The software problem is hard to find relative to the hardware. It is not as intuitive as the hardware. Therefore, the switch editor reminds everyone that they must make a record of the faults to accumulate their own experience in identifying switch software faults.


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