What are the common faults of switches?

What are the common faults of switches?

Customers often report screen delays, freezes, and other phenomena. There are many reasons for this phenomenon, but in most cases, the switch's configuration is not reasonable enough, resulting in insufficient bandwidth. Because switches are widely used in the network, the probability of failure of switches is much higher than that of routers and hardware firewalls. The switch faults are generally divided into two categories: hardware faults and software faults.

I. Switch hardware failure

Hardware faults are divided into the switch power supply, control board, module, port, and other component faults, which can be divided into the following categories.

1. Power failure:

Due to an unstable external power supply, aging power lines, lightning strikes, etc., the power supply may be damaged, or the fan will stop so that it cannot work normally. It also often happens that other parts inside the machine are damaged due to the power supply.

If the POWER indicator on the panel is green, it is normal; if the indicator is off, the switch is not powered normally. If conditions permit, you can choose professional lightning protection measures (lightning arrester) to avoid lightning damage to the switch.

2. Port failure:

If the optical fiber plug is accidentally dirty, it may cause the optical fiber port to be polluted and unable to communicate normally. Furthermore, if the size of the crystal head purchased is too large, it is easy to damage the port when inserted into the switch. In addition, if the twisted pair connected to the port has been 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, the port fault is that one or several ports are damaged. You can determine whether it is damaged by replacing the connected ports.

3. Module failure:

A switch comprises many modules, such as stacking modules, management modules (also called control modules), and expansion modules. The chances of these modules failing are small, but they can suffer huge financial losses. Such failures may occur if you are not careful when inserting or removing modules, if you are bumped when moving the switch, or if the power supply is unstable.

When troubleshooting such faults, first ensure that the power supply of the switch and modules is normally supplied, then check whether each module is inserted in the correct position, and finally, check whether the cables connecting the modules are normal. When connecting the management module, it is also necessary to consider whether it adopts the specified connection rate, whether there is a parity check, whether there is data flow control, and other factors. Finally, when connecting an expansion module, it is necessary to check whether the communication mode is matched.

4. Control board failure:

Each module of the switch is plugged into the control board. If the environment is humid, the circuit board is short-circuited due to moisture, or the components are damaged due to high temperature, lightning strikes, and other factors, the circuit board will not work correctly. For example, poor heat dissipation or too high ambient temperature causes the temperature inside the machine to rise, causing the components to burn out.

In the case of a normal power supply from the external power supply, if all the internal modules of the switch cannot work normally, it may be that the control board is broken, and the only way is to replace the control board.

5. Cable failure:

Cable failure often causes the switch system or port to not work correctly, such as the connector is not plugged in tightly, the cable is arranged in the wrong order or is not standardized, the cable should be connected with a crossover cable, but a straight cable is used. Two of the optical cables are used. Fiber cross-connections and wrong line connections lead to network loops, etc. Therefore, when building a computer room, we must first do a good job constructing lightning protection and grounding, power supply, indoor temperature, indoor humidity, anti-electromagnetic interference, anti-static and other environments to provide a suitable environment for the normal operation of the network equipment.

II. Switch software failure

The switch's software failure refers to the system's failure and configuration, which can be divided into the following categories.

1. System error:

A refreshable read-only memory inside the switch saves the software system necessary for this switch. This error is also the same as our common Windows and Linux. However, due to design reasons, some loopholes will indirectly lead to switching full load, packet loss, and wrong packets. Therefore, the switch system provides methods such as Web and TFTP to download and update the system.

2. Improper configuration:

If we are unfamiliar with switches or due to the different configurations of various switches, administrators often make configuration errors when configuring switches. For example, improper VLAN division leads to network failure, ports are closed by mistake, and the mode configuration of switches and network cards does not match. If you cannot ensure a problem with the user's configuration, please restore the factory default configuration and then configure it step by step.

3. Lost password:

Once you forget your password, you can recover or reset the system password by following specific steps. Others are as simple as pressing a button on the switch. Others require specific steps to resolve.

4. External factors:

Due to the existence of viruses or hacker attacks, a host may send a large number of data packets that do not meet the encapsulation rules to the connected port, causing the switch processor to be overly busy and causing the data packets to be too late to forward, which in turn leads to buffer overflow and packet loss. Furthermore, if many broadcast packets occupy the network for a long time, normal point-to-point communication cannot be carried out normally, and the network speed will be slowed down or paralyzed.

Generally speaking, software faults should be more difficult to find than hardware faults, and it may not cost too much money to solve the problem, but it will take more time. It is best to develop the habit of keeping a log of your usual work. Whenever a fault occurs, timely record the fault phenomenon, fault analysis process, fault solution, fault classification, summary, etc., to accumulate their own experience.