First, the switch failure classification:

Switch failure can generally be divided into two major categories of hardware failure and software failure. Hardware failure mainly refers to the switch power, backplane, module, port and other components of the fault, can be divided into the following categories.

(1) Power failure:

Due to external power supply instability, or power line aging or lightning and other reasons leading to power damage or fan stop, which can not work properly. Damage to other parts of the machine due to power supply is also frequent.

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 is not powered properly. This kind of problem is easy to find, is also easy to solve, but also the most easy to prevent.

For this type of failure, the first supply of external power supply should be done, generally through the introduction of independent power lines to provide independent power supply, and add a regulator to avoid instantaneous high voltage or low voltage phenomenon. If the conditions permit, you can add UPS (uninterruptible power supply) to ensure the normal power supply switch, and some UPS to provide voltage regulator, and some do not, when the choice should pay attention. In the room to set up professional lightning protection measures to avoid lightning on the switch damage. There are many professional companies to do lightning protection projects, the implementation of network cabling can be considered.

(2) port failure:

This is the most common hardware failure, whether it is fiber port or twisted pair RJ-45 port, in the plug connector must be careful. If you accidentally dirty the fiber plug, it may cause the fiber port to pollute and not communicate properly. We often see a lot of people like to plug the plug, theoretically it is possible, but this also inadvertently increased the port failure rate. Do not care when handling, may also cause physical damage to the port. If you buy the crystal head size is too large, insert the switch, it is easy to damage the port. In addition, if the twisted pair on the port is exposed to the outside, if the cable is hit by lightning, it will cause the connected switch port to be damaged, or cause more unpredictable damage.

Under normal circumstances, the port failure is one or several ports damaged. Therefore, after excluding the failure of the computer connected to the port, you can replace the port, to determine whether it is damaged. In the event of such failure, you can clean the port with alcohol cotton balls after the power is turned off. If the port is indeed damaged, it can only replace the port.

Second, the switch software failure:

Switch software failure refers to the system and its configuration on the failure, it can be divided into the following categories.

(1) System error:

The switch system is a combination of hardware and software. There is a refreshable read-only memory inside the switch that preserves the software systems necessary for this switch. This kind of error and our common Windows, Linux, due to the design of the reasons, there are some loopholes, when the conditions are appropriate, will lead to full load, packet loss, wrong package and so on. So the switch system provides such as Web, TFTP, etc. to download and update the system. Of course, there may be an error when upgrading the system.

For such problems, we need to develop the habit of regularly browsing the equipment manufacturers website, if there is a new system or new patch, please update.

(2) improperly configured:

Beginners are not familiar with the switch, or because the switch configuration is not the same, the administrator often configure the switch will appear when the configuration error. Such as VLAN partition is not correct lead to the network barrier, the port was wrong to close, switch and network card configuration does not match and other reasons. Such failures are sometimes difficult to find and require some experience to accumulate. If you can not ensure that the user's configuration is faulty, please restore the factory default configuration, and then step by step configuration. It is best to configure before reading the manual, which is one of the habits to be developed. Each switch has a detailed installation manual, user manual, deep into each module has a detailed explanation. As a lot of switches manual is written in English, so the English bad users can consult the supplier's engineers to do the specific configuration.

(3) Password loss:

This may have been experienced by every administrator. Once you forget your password, you can restore or reset the system password with some operational steps. And some are relatively simple, in the switch press a button on it. While others need to be through a certain number of steps to solve.

This situation is generally forgotten in the human or switch failure caused by data loss will occur.

(4) External factors:

Due to the presence of a virus or hacker attack, it is possible that a host sends a large number of packets that do not conform to the encapsulation rules to the connected port, causing the switch processor to be too busy, causing the packet to be unreachable, resulting in a buffer overflow Package phenomenon. There is also a situation that is broadcast storm, it will not only take up a lot of network bandwidth, but also will take 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 of communication can not be normal, the network speed will slow down or paralyzed.

A network card or a port failure, are likely to trigger a broadcast storm. Because the switch can only split the collision domain, and can not split the broadcast domain (in the case of no VLAN), so when the number of broadcast packets accounted for 30% of the total communication, the network transmission efficiency will be significantly reduced.

In general, the software failure should be harder to find than the hardware failure, solve the problem, you may not need to spend too much money, and need more time. It is best in the usual work to develop the habit of recording logs. Whenever a failure occurs, do a good job in time to fault records, fault analysis process, fault solution, fault classification summary work to accumulate their own experience. For example, sometimes in the configuration, for various reasons, then did not have an impact on the network or did not find the problem, but perhaps a few days later the problem will gradually appear. If there is a log record, you can think of whether the configuration of a few days ago wrong. Because a lot of time will ignore this point, that is in other areas of the problem, when a lot of detours, only to find the problem. So it is necessary to log and maintain information.