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How Do I Troubleshooting Cisco Switches Hardware Issue
Jul 05 , 2022 1330

During the daily use of the switch, we may encounter some failures, the faults of the switch are mainly divided into two categories. The first type is a hardware failure, which is a problem on the hardware. The second type is software failure, which is a problem inside the switch. Now let's troubleshooting the hardware failure.

Hardware failures can be divided into switch power failures, backplane failures, module failures, and port failures. Below is how to troubleshooting each hardware issue.

1. How to troubleshooting Cisco Switch power issue

Switches Hardware Issue.jpg

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. 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. These 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 UPS (uninterruptible power supply) to ensure the normal power supply of the switch, and some UPS provide voltage regulation function, and some do not, you should pay attention to when choosing.

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. How to troubleshooting switch port issue


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, the connected switch port will 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. How to troubleshooting Cisco switch module issue


A switch is composed of many modules, such as a stacking module, a management module (also called a control module), and an expansion module. 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 is 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 replacement.

4. How do I trouble shooting Cisco switch backplane issue

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. How to trouble shooting Cisco switch cable issus

In fact, 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 standardized. 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, and the wrong line connection causes the network loop. Wait.

From the above several hardware issues, the poor environment of the equipment room can easily lead to various hardware failures. Therefore, when building the equipment room, we must first do lightning protection 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.

The above is the hardware problem encountered by the Cisco switch. If you have any other questions or needs, please contact our online customer service. Linknewnet.com provide used or brand new Cisco switches with the affordable price.

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